PICO PicoCricket Reference Manual

The Playful Invention Company

PicoCricket

Reference Guide

Version 1.0

Credits

Design Team

Mitchel Resnick Brian Silverman Paula Bontá Robbie Berg Natalie Rusk

Industrial Design: Smart Design

Graphic Design: Big Blue Dot

We would like to give special thanks to:

PICO staff members Chad Burt and Mike Durcak for their invaluable ideas and enthusiasm.

Diana Gee Silverman for the on-line help, Danny Lutz for the sounds, and Lawrence Shubert for guiding PICO through the intricate aspects of compliance testing and manufacturability.

staff from the Playful Invention and Exploration (PIE) project for developing new Cricket activities, particularly Keith Braaﬂadt, Stephanie Hunt, Chip Lindsey, Hideki Mori, Kristen Murray, Mike Petrich, Margaret Pezalla-Granlund, Natalie Rusk, Michael Smith-Welch, Karen Wilkinson, and Diane Willow.

MIT researchers and students who contributed to Cricket R&D, particularly Andy Begel, Robbie Berg, Rahul Bhargava, Rick Borovoy, Fred Martin, Bakhtiar Mikhak, Mitchel Resnick, and Brian Silverman.

the LEGO Company for its continuing support, particularly Kjeld Kirk Kristiansen, Lisbeth Valther Pallesen, Jens Maibom, and Erik Hansen.

© 2006. The Playful Invention Company Inc. All rights reserved. This material may not be reproduced, displayed, modiﬁed, or distributed without the express prior written permission of the copyright holder.

Contents

Credits 2

lntroduction 4

PicoBlocks

Blocks Summary 12 Blocks - Detailed by Category 1

Melody and Rhythm Editors 3

The PicoBlocks Text Language 3

Error Messages 4

8

4

0

5

8

lntroduction

Welcome! This Reference Guide provides an overview of the PicoCricket family of parts and the PicoBlocks software used to program the PicoCricket.

If you are just getting started with the PicoCricket and PicoBlocks, please go through the Setup Guide and Getting Started booklet ﬁrst, to get an overall introduction. If you want more detailed information, then come back to this Reference Guide.

We are continually updating the Reference Guide. You can download the latest version from

www.picocricket.com/support

PicoCricket Family

The PicoCricket family includes the following parts:

PicoCricket

The PicoCricket is a tiny computer that can control things in the world. The Cricket has four ports where you can plug in other devices, such as sensors, motors, and lights. You can plug any of these devices into any of the Crickets ports.

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The Cricket has three types of indicator lights:

The on-off indicator light turns on (orange) when you turn on the Cricket. If the batteries are low, the light ﬂashes rapidly when you turn on the Cricket.

The program-running indicator light turns on (green) when the Cricket is running a program, and it changes color to amber when the Cricket is running two programs at the same time.

The IR-communication indicator lights ﬂash (yellow) when the Cricket is communicating through its infrared transmitter.

If you push the Cricket button while the Cricket is running a program, the program will stop. If you push the button when no program is running, the Cricket will re-run the last program that it ran.

Even when you turn the Cricket off, it remembers the last program that it ran. So if you run a program, turn off the Cricket, turn it back on later, and push the button, the Cricket will run the program again.

Beamer

The Beamer transmits information (via infrared signals) from your computer to your Cricket. When you write a program using PicoBlocks software on your computer, you send the program to the Cricket via the Beamer.

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5

The PicoCricket Kit includes a USB-serial cable for connecting the Beamer to a USB port on your computer. Alternatively, you can connect the Beamer to a serial port, using a standard serial cable (not included).

When you are sending information to the Cricket, make sure that the antennas on the Beamer are facing towards the antennas on the Cricket. While the Beamer and Cricket are communicating, the indicator lights in the antennas will ﬂash yellow (on both the Beamer and the Cricket).

The Beamer has a range of about a 1 meter. Note that a Beamer can communicate with one Cricket at a time. If you have multiple Crickets, make sure that only one of them is in range of the Beamer at any time.

Actuators

Actuators are devices that make things happen in the world. The PicoCricket Kit includes four types of actuators: colored lights, sound box, motor (with motor board), and numeric display.

Name Description Programming Blocks Icon

Light You can set the color of the light across

the entire rainbow, from red to violet. You can also set the brightness of the light.

Sound

Box

Motor

and Motor Board

Display

The sound box is a small synthesizer that can play notes, melodies, sound effects, and rhythms. PicoBlocks software includes special editors for creating melodies and rhythms. You can set and change which instrument will play notes and melodies.

The motor board connects to the Cricket, and the LEGO motor connects to the motor board. You can turn the motor on and off, and set its power and direction.

The three-digit display can show any number between 0 and 999. It is especially useful for displaying sensor values.

note

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Sensors

Sensors allow your Cricket to respond to sounds, lights, or other changes in its environment.

Name Description Programming

Blocks

Light

Sensor

Reports the brightness of light. For example, you can use the light sensor to detect when someone casts

brightness

a shadow with their hand – or when the sun shines through the window.

Sound Sensor

Reports the loudness (or volume) of sound. For example, you can use the sound sensor to detect when someone claps their hands – or when someone

loud?

loudness

sings into the sensor.

Touch

Sensor

Reports if the button is pressed. For example, you can write a program that makes something happen

touch?

(a motor spinning or a light changing color) when someone presses the touch sensor.

Resistance

Sensor

Reports the resistance in the circuit formed by the alligator-clip cables. If you put different materials

connected?

(for example, play-dough or a banana) between the alligator clips, the resistance will change. You can also

resistance

use the resistance sensor to detect when the alligator clips are touching each other (or connected through a conductive material, such as aluminum foil).

Icon

Each of the programming blocks will be described further in the following pages. For examples of how to use the actuators and sensors, see “Magic Lantern” and other sample

project placemats.

Cricket Care

1. Remember to turn off the Cricket when you aren’t using it.

2. If the orange on-off indicator light ﬂashes, it means that your Cricket is running out of batteries. To change the batteries, follow the instructions in the Setup Guide.

3. Be gentle with the cable connectors. If you push the connectors up and down with too much force, the connectors will break.

4. Keep your Cricket devices away from water and other liquids.

5. If your Cricket is misbehaving, check the Troubleshooting section in our website:

www.picocricket.com/troubleshooting

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7

PicoBlocks

Overview

PicoBlocks is a programming language designed speciﬁcally for programming your Cricket. With PicoBlocks, you create programs by snapping graphical blocks together into stacks.

These are the tools

Click on the tabs to get different categories of blocks

This is a stack

This is your Workspace Drag and drop blocks to create your stacks

Blocks Palette

Tools

?

The tools are used for taking different actions on the blocks, such as copying blocks, deleting blocks, or sending blocks to the Cricket. When you click on a tool, the cursor turns into that tool.

Arrow

Use the Arrow to drag blocks from the Blocks Palette to the Workspace, or within the Workspace. To move an entire stack, drag from the top block. Dragging a block from the middle of a stack will also move any blocks attached beneath the one you are dragging.

2

Undo

STOP

You can get rid of blocks by dragging them off of the Workspace, in any direction. If you delete blocks by mistake, click Undo

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Magic Wand

Use the Magic Wand to run a program. When you click on a block or stack with the Magic Wand, it sends the program to the Cricket and tells the Cricket to run the program.

forever

chirp

setlight

color

brightness

You can use the Magic Wand to click on blocks in the Blocks Palette, the same way you click on blocks in the Workspace. This feature is useful for testing out a block.

Another way to run a program is by double-clicking with the Arrow, instead of single-clicking with the Magic Wand.

Scissors

Use the Scissors to get rid of blocks. Clicking on a block in a stack will also cut all blocks attached below it.

If you delete blocks by mistake, click Undo

You can also get rid of blocks by dragging them out of the Workspace.

motor

on

waituntil

reverse

touch?

motor

on

waituntil

touch?

motor

onfor

10

Stamper

Use the Stamper to copy blocks and stacks. Click once to copy, then move to a new location and click a second time to paste. When you click on a block in a stack with the Stamper, it also copies all blocks attached below it.

You can switch to the Stamper temporarily using Ctrl +

motor

on

waituntil

reverse

motor

onfor

motor

onfor

touch?

10

, or +

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9

Help

?

Use the Help tool to get more information. If you click on a block with the Help tool, a window with more information will appear.

setlight

color

wait

setlight

color

?

wait

10

2

Second Wand

Use the Second Wand to tell the Cricket to run a second stack at the same time as it is running something else. To run two stacks, click on one with the Magic Wand, then the other with the Second Wand.

For example, you can use the Second Wand to start background music or display sensor values while another program is running.

melody1

2

forever

2

display

brightness

Tags

Use the Tags tool when you want to tell two devices of the same type to do different things. For example, if you plug two colored lights into a Cricket, and then send a setlight-color command to the Cricket, the Cricket will change the color of both lights. If you want to turn each light to a different color, you need to use Tags.

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Each of the four ports on the Cricket is labelled with a different number of dots. If you want to send a command to a particular port, then you need to “tag” the block with the appropriate number of dots. For example, if you plug colored lights into ports and , then you can set the color of each light individually with the following blocks:

setlight

color

setlight

color

To tag a block, click on the appropriate dot in the Tags tool, then click on the block that you want to tag.

setlight

color

To remove a tag from a block, click in the center of the Tags tool and then click on the block.

setlight

color

STOP

Stop

Click on the Stop sign to stop all programs running on the Cricket. Make sure that the Cricket is “in sight” of the Beamer. Alternatively, you can stop programs on the Cricket by pressing the white button on the Cricket. Note that stopping programs on the Cricket does not turn off lights attached to the Cricket. If you want to turn off the lights, slide the on-off switch into the off position.

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11

Blocks Summary

This list shows all of the basic blocks in PicoBlocks.

setlight

color

setlight

power

light

turns the light off

off

display

chirp

note

play

sound

set

inst

the next note or melody

set

for the next note, melody

tempo

displays a value on the display

makes the Cricket chirp

plays a note (pitch and duration)

Kitten

Piano

set

volume

sets the light’s color

sets the light’s power

plays a sound

sets an instrument for

sets the tempo or volume

or rhythm

connected?

reports true if the resistance sensor

detects a resistance of 0

resistance

reports a value from the

resistance sensor

beamIR

infrared from another Cricket

newIR?

beamed a new value by infrared

beams a value to another Cricket

reports a value beamed by

IR

reports true if another Cricket has

timer

reports the Cricket’s timer value

in 100ths of a second

reset

timer

sets the Cricket’s timer to 0

waits a number of ticks (where 10

wait

ticks = 1 second)

waituntil

waits until the condition is true

motor

on

motor

onfor

period of time

reverse

this

way

set

power

touch?

pressed

brightness

sensor

motor

turns motor on or off

off

turns the motor on for a certain

reverses the motor’s direction

that

sets the motor’s direction

way

sets the motor’s power

reports true if the touch sensor is

reports a value from the light

reports true if the sound sensor

loud?

detects a loud sound

loudness

reports a value from the sound

sensor

forever

repeat

repeats a block or stack

a certain number of times

repeats a block or stack

if

condition is true

if

runs a block or stack if the

then

if condition is true, run one stack; if not, run

then else

the other stack

stopall

stops everything

stop

stops this stack

stack

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Blocks Summary - Continued

creates space between blocks,

so that they don’t overlap one another

number

+

and

or

not

speciﬁes a number (click to highlight, and then type in a number)

x

-

r a n d o m

/

computes arithmetic operations

picks a random value between the two numbers

> <

makes a comparison between two numbers and reports true or false

=

reports true if both conditions are true

reports true if either condition is true

reports the opposite of a condition

sits on top of stack, and allows you to type in name for the stack

store in

box1

store in

box2

box1

set and report values for variables

box2

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13

Blocks - Detailed by Category

Light Blocks

setlight

color

which color

waits for 4 ticks

turns the light pink (color

setlight

color

wait

setlight

color

turns the light blue

4

5

5)

Sets the LED’s color and turns it on. You can set the color by using the color slider, or choosing a number between 0 and 100. Colors are numbered as follows:

pink red yellow aqua light blue violet 0 20 40 60 80 100

10 30 50 70 90 magenta orange green cyan blue

Default value:

setlightcolor 0

setlight power

how bright

waits for 40 ticks

sets light back to full power

setlight power

wait

setlight power

40

100

sets light to half power and turns it on

setlightpower can take numbers between 0 (no light) and 100 (full power). You can set the power by using the slider or a number block. Default value: setlightpower 100

light

off

setlight

turns the light green

color

waits for 15 ticks

turns the light off

wait

light

off

15

lightoff turns the light off.

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display

display what

r a n d o m

display

15

95

displays a random number

Displays a value on the display

Sound Blocks

The Sound palette starts with six basic blocks (shown below). You can create additional blocks with the Melody and Rhythm editors. See page 3 rhythms.

0 for information on creating melodies and

chirp

makes the Cricket chirp once

Making the Cricket chirp is a good way to test whether your computer is communicating properly with the Cricket.

how high a note

note

for 5 ticks (half a second)

50

5

plays the note 50

how long note can play notes between 0 (lowest) and 100 (highest). You can play notes with the Cricket speaker or with the Sound Box (but it will sound much better with the Sound Box). For composing melodies, we suggest using the Melody Editor rather than putting individual note blocks together. Default value: note 50 2

play

sound

plays this sound (kitten)

play

sound

play

sound

Select a sound with the slider or enter a number between 0 and 100. There are 24 sounds available (see table below).

Kitten

23

plays sound 23 (horse)

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# Sound # Sound # Sound 1 Piano 9 Claps 17 Cricket 2 Flute 10 Cowbell 18 Fairydust 3 Pizzicato 11 Maracas 19 HighQ 4 Strings 12 Slap 20 Dog 5 Trombone 13 Timbale 21 Rooster 6 Vibes 14 Wood Block 22 Goose 7 Agogo 15 Guiro 23 Horse 8 Cabasa 16 Bloops 24 Kitten

All these sounds require the Sound Box. Sound 0 is the Cricket chirp. For numbers greater than 24, playsound plays the next sound in the list: 25 plays sound 1, 26 plays sound 2, ... and so on. Default value:

playsound 24 (kittten)

set

inst

plays note 16 (on the trombone) for 5 ticks (half a second)

setinstrument which instrument

set

inst

Trombone

16

sets instrument to trombone

note

5

Sets the instrument to be used for subsequent notes or melodies. You can select the instrument with the slider or attach a number between 0 and 100. setinstrument 0 sets the note or melody with the Cricket’s beeper. The inputs for setinstrument are the same as for playsound (shown in table above). You can use any sound as an instrument, but they don’t all work well. Default value: setinstrument 1 (piano)

set

tempo

set

tempo

plays melody1 at the fastest tempo

melody1

settempo takes values between 0 (slowest) and 100 (fastest). The fastest tempo (100) equals to 240 bpm (beats per minute), while the slowest (0) equals to 60 bpm. Default value: settempo 50 (120bpm)

100

sets tempo to 100 (fastest)

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set

volume

set

volume

30

sets the volume to 30 (quiet)

plays note 50 for 5 ticks (half a second)

note

50

5

setvolume takes values between 0 (no sound) and 100 (loudest). Setvolume only works with the Sound Box. Default value:

setvolume 80

Action Blocks

motor

on

waits for 20 ticks (2 seconds)

turns the motor off

motoroff makes the motor coast to a stop. If you want the motor to stop more abruptly or more gently, try using the brake and coast commands in the PicoBlocks Text Language.

motor

off

motor

on

wait

motor

off

20

turns the motor on

motor

onfor

how long

motor

onfor

20

turns on motor for 20 ticks (2 seconds)

10 ticks = 1 second Turns the motor on for the speciﬁed number of ticks, then turns it off. motoronfor does the same thing as a stack with motoron, then wait, then motoroff. Default value: motoronfor 10

reverse

changes direction

goes the other way for 40 ticks

motor

onfor

reverse

motor

onfor

20

40

motor goes one way for 20 ticks

reverse causes the motor to change the direction in which it is spinning. reverse does not turn the motor on, it only changes the direction.

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this

way

that way

this

way

sets motor to one direction

turns on for 10 ticks

sets motor to the opposite direction

turns on again for 10 ticks

motor

onfor

that way

motor

onfor

10

thisway sets the motor in one direction, thatway sets it in the other direction. Which direction is which depends on how the motor is plugged in. thisway and thatway do not turn on the motor, they only set the direction.

set

power

turns the motor on

set

power

motor

on

10

sets motor power to 10

setpower takes values between 0 (no power) and 100 (strongest power). setpower does not turn on the motor, it only sets the power. Default value: setpower 100

Sensors Blocks

touch?

is the touch sensor

forever

if

touch?

then

chirps if the touch sensor is pressed

chirp

touch? reports true when the touch sensor is being pressed. The example above will make the Cricket chirp continuously while you are pressing the button on the touch sensor. If you want to chirp only once each time you push the button, you should make a stack similar to the one shown below:

being pressed?

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forever

waituntil

chirp

touch?

sensor

brightness

display

waituntil

brightness

not

touch?

displays the number reported by the

waits until the touch

is released

light sensor

brightness reports numbers between 0 (no light) and 100 (lots of light)

loud?

waituntil

loud?

waits until the sound sensor

detects a sound

turns the light pink

setlight

color

loud? reports true if the sound sensor detects a sound with loudness greater than 15.

loudness

sensor detects a clap

turns the light green

waituntil

setlight

loudness

>

30

waits until the sound

color

loudness reports numbers between 0 (no sound) and 100 (loud sound).

connected?

to detect a connection

forever

waituntil

connected?

waits for resistance sensor

chirp

when a connection is sensed, it chirps

connected? reports true if the resistance sensor detects a resistance of less than 50.

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19

resistance

forever

display

resistance

displays the number reported

by the resistance sensor

resistance reports numbers between 0 (no resistance) and 100 (lots of resistance). If you are getting numbers in a very narrow range, you should adjust the sliders as follows:

resistance

try this if you aren’t getting low numbers

try this if you aren’t getting high numbers

Remember to use the magic wand after moving the sliders

beamIR

forever

beamIR

0

r a n d o m

100

beams a number between

0 and 100

wait

10

beamIR beams a number to another Cricket via infrared (IR). To use this command, you need two Crickets: one beaming the IR signal, the other receiving the IR signal. See example for IR block below. We recommend using numbers in the range 0 to 100. Numbers outside this range may produce unexpected results.

newIR?

IR

forever

waituntil

newIR?

waits for a new IR message from

another Cricket

IR

plays a note based on the number received

note

10

IR stands for Infra Red. newIR? reports true if a new infrared (IR) signal has been received. IR reports the value of the latest infrared signal received.

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reset

timer

reset

timer

is greater than 500

turns on motor

waituntil

motor

on

sets timer to 0

timer

>

waits until the timer

500

100 ticks of the timer equals 1 second

Flow Blocks

wait

waits for 20 ticks (2 seconds)

turns the light off

setlight

color

wait

light

off

turns the light pink

20

10 ticks equals 1 second Default value: wait 10

waituntil

waits until the touch sensor is pressed

turns off motor

Waits until

the condition is true.

motor

on

waituntil

motor

off

turns on motor

touch?

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21

forever

To stop the forever, push the button on your Cricket or click on

motor

onfor

wait

3

repeat this forever

3

STOP

repeat

how many times

repeat

10

place here whatever you want to do after the repeat ﬁnishes

motor

onfor

reverse

4

repeat this 10 times

if

if this is true...

then

forever

if

connected?

then

this will happen

chirp

place here whatever you want to do after the if ﬁnishes

If the condition reports true, then the Cricket will run the blocks below the word “then.”

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PicoBlocks - Reference

if

is this true?

then else

forever

if

touch?

then else

motor

on

motor

off

otherwise do this if true, do this If the condition reports true, then run the blocks under the word “then”; if not, run the blocks under “else”.

stopall

motor

on

if this is true...

forever

if

everything stops (including the motor)

chirp

touch?

then

stopall

Stops all programs and motors (but leaves lights on). stopall is equivalent to pressing the button on the Cricket.

stop

stack

forever

this stack stops

stopstack stops only the current stack. You can use this block to stop one stack while continuing another stack.

if

chirp

touch?

then

stop

stack

if this is true...

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23

For example:

colors

forever

if

touch?

colors will stop when the touch sensor is pressed, yet the other stack will continue. The light will be turned off and melody1 will be played.

setlight

color

then

stop

stack

brightness

Vertical Spacer

Without Spacers With Spacers

colors

light

off

melody1

repeat

motor

onfor

10

motor

onfor

4

reverse

repeat

4

motor

onfor

10

motor

onfor

reverse

4

Use spacers to keep the blocks from overlapping. (Adding spacers does not change the way the program runs.)

Horizontal Spacer

Without Spacers With Spacers

repeat

motor

onfor

10

motor

onfor

4

reverse

repeat

4

motor

onfor

10

motor

onfor

4

reverse

4

Use spacers to keep the blocks from overlapping. (Adding spacers does not change the way the program runs.)

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PicoBlocks - Reference

Numbers Blocks

number

turns on motor for 20 ticks (2 seconds)

Click on Default Value: 10 Numbers in PicoBlocks are limited to integers between -32768 and +32767.

adds two values this plus that

+

turns on motor for 10 plus the value of the brightness sensor (for example, if the brightness sensor is 30, motor turns on for 40 ticks).

subtracts two values this minus that

-

turns on light with a power of 100 minus the value of the brightness sensor (for example, if the brightness sensor is 60, light power will be 40).

to type in a number. accepts negative numbers.

set

power

motor

onfor

motor

onfor

setlight

power

50

20

10

100

sets motor power to 50 (half power)

+

-

brightness

multiplies two values this multiplied by that

x

r a n d o m

setlight

color

Sets the light’s color to a random number multiplied by 10 (for example, if the random number is 7, sets the color to 70 which is cyan).

divides the ﬁrst value by the second value

/

this divided by that

turns on motor for the value of brightness sensor divided by 10 (for example, if the brightness sensor is 50, motor turns on for 5).

0

10

motor

onfor

x

brightness

10

/

10

PicoBlocks - Reference

25

r a n d o m

reports a random number between this and that

10

r a n d o m

turns on motor for a random number of

50

motor

ticks (in this case it could be 10, or 50, or

onfor

anything in between...) Default value: random 0 100

>

if this is greater than that...

forever

if

this will happen

number1 > number2 reports true if number1 is greater than number2.

brightness

then

chirp

>

50

<

if this is less than that...

forever

if

this will happen

number1 < number2 reports true if number1 is less than number2.

brightness

then

chirp

<

60

=

if this is equals that...

forever

if

this will happen

number1 = number2 reports true if the two numbers are equal.

brightness

then

chirp

=

50

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PicoBlocks - Reference

and

waits until this and that are both true...

waituntil

touch?

then, this will happen

chirp

and

loud?

and reports true if the result of the ﬁrst condition (touch?) and the second condition (loud?) are both true.

or

if this or that is true...

forever

if

this will happen

touch?

then

chirp

or

loud?

or reports true if the result of the ﬁrst condition (touch?) or the second condition (loud?) is true.

not

waituntil

motor

on

is not pressed

waituntil

motor

off

touch?

not

touch?

waits until the touch sensor

not reports true if the condition is false. not reports false if the condition is true.

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27

My Blocks

You can use this block to give a name to a stack of blocks – and create a new

block that does the same thing as the entire stack. Here’s how:

1. attach the block at the top of the stack you want to name

chirp

2. click and type a name 3. a new block with that name appears in

4. Use it in other stacks

4

2chirps

chirps 8 times

box2

Use these blocks for setting and

store in

box1

repeat

store in

box2

retrieving the values of variables.

store in

Use

box1

random number

to store a value, and use

store in

box1

setlight

turns a light that random color

waits for 5 ticks

color

wait

setlight

turns a second light the same color

color

box1

5

box1

30

r a n d o m

box1

to retrieve it.

49

box1 stores a

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PicoBlocks - Reference

To change the name of a variable, drag it into the workspace, click on it, and type in the new name.

store in

box1

setlight

color

10

box1

store in

my-color

setlight

color

my-color

rename the block

When box1 is renamed in the workspace, the blocks in the palette are automatically updated.

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29

Melody and Rhythm Editors

PicoBlocks has two editors for creating music: a Melody Editor and a Rhythm Editor.

To create a new melody or rhythm (or to edit an existing one), ﬁrst click on the Sound tab. At the bottom of Sound palette are two buttons, one for opening the Melody Editor, the other for opening the Rhythm Editor.

After you create a new melody or rhythm, it will appear as a new block in the Sound palette. You can drag these music blocks into the workspace, and connect them to stacks, just as you would with any other block in PicoBlocks.

These blocks were created using the Melody Editor and Rhythm Editor.

Opens the Melody Editor

Opens the Rhythm Editor

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Melody Editor

Click on to open the Melody Editor.

If this is your ﬁrst melody, you will see a blank Melody Workspace for creating your melody. If you have previously created melodies, you will see one of your existing melodies in the Melody Workspace. You can edit this melody – or select one of your other existing melodies to edit (by clicking on a block in the palette on the left side) – or create a new melody (by clicking on the “Create” button at the top-left).

To add notes to your melody, either click on the keyboard, or click directly in the Melody Workspace.

When you are ﬁnished creating your melody, click and exit the Melody Editor.

Click here to create a new melody

Middle C

You can import and export melody ﬁles with extension .pbm

To create a new note, click on the keyboard or directly in the Melody Workspace

click here to insert a rest

Melody Workspace

OK

to turn your melody into a block

Change instrument, volume, or tempo

Insertion point: the next note pressed on the keyboard will start here

Drag this end to change length of note

Drag here to make the Melody Workspace bigger or smaller

Select the duration

Click here to save the melody as a block and exit the Melody Editor

Play or stop

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31

twinkle

All of your melodies appear at the left of the Melody Editor. Click on the melody that you want to edit.

To change the name of a melody, click on the block and type a new name.

Use

to make a copy of a melody. Use

to delete melodies.

Drag on the background to select notes. Move the selected notes by dragging them to other location.

You can also copy

and play

the selection.

, cut

You can also play the selection by double clicking on it.

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Rhythm editor

Click on to open the Rhythm Editor.

If this is your ﬁrst rhythm, you will see a blank Rhythm Workspace for creating your rhythm. If you have previously created rhythms, you will see one of your existing rhythms in the Rhythm Workspace. You can edit this rhythm – or select one of your other existing rhythms to edit (by clicking on a block in the palette on the left side) – or create a new rhythm (by clicking on the “New Rhythm” button at the top-left).

When you are ﬁnished creating your rhythm, click and exit the Rhythm Editor.

Click here to create a new rhythm

You can import and export rhythm ﬁles with extension .pbr

Click or drag here to create a note

OK

to turn your rhythm into a block

Change volume, or tempo

Drag here to make the Rhythm Workspace bigger or smaller

Click here to save the rhythm as a block and exit the Rhythm Editor

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Loop, play or stop

33

All of your rhythms appear at the left of the Rhythm Editor. Click on the rhythm that you want to edit.

To change the name of a rhythm, click on the block and type a new name.

Use to make a copy of a rhythm. Use to delete rhythms.

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The PicoBlocks Text Language

Overview

PicoBlocks lets you construct computer programs by snapping different blocks together, like pieces of a puzzle. This approach makes it easy to get started; different kinds of blocks have different shapes and can only snap together in certain ways. The shapes of the pieces provide a lot of guidance as to how structure your programs, helping you build programs that work the way you want them to work. But if you try to write longer programs you may ﬁnd that using the blocks can get cumbersome. For example, all of your stacks may no longer ﬁt a the

screen at the same time. Also, there are some advanced programming features that are not available using the blocks. As your programs become longer and more complex, you may want to consider using the Text Language that is available from within the PicoBlocks software. The PicoBlocks Text Language is similar to the computer language Logo. (For more information on Logo see www. logofoundation.org.) To begin writing programs in the Text Language, click on the text icon located in the lower left hand corner of the PicoBlocks Workspace. The Text Language Workspace, shown in the ﬁgure below, will appear.

Click on the text icon to switch to the text language Workspaces

Click here to switch back and forth between the Text and the Blocks Workspaces

Procedure Area

Deﬁne new words here

Command Center

Type commands here and

then press Enter

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35

Try typing the following commands in the Command Center. (Press the Enter key to run each line.)

chirp The Cricket chirps! chirp wait 2 chirp The Cricket chirps twice.

Note that spaces are very important in the Text Language; they are used to determine where words start and end. For example, if you leave out the space between wait and 2 in the last example you will get an error message that says “I don’t know how to wait2”. This is because PicoBlocks does not understand the word wait2.

Each block in PicoBlocks has an associated word in the text language. The general rule for ﬁnding the

1

name of the word in the text language that is associated with a particular block is a very simple one

:

Just copy what’s written on the block, leaving out a space if there is one.

For example, plug a light into your Cricket and type the following in the Command Center:

setlightcolor 20 The light turns red

Note that there are no spaces in the word setlightcolor.

Now try typing the following line in the Command Center:

repeat 5 [chirp wait 2]

In the Text Language square brackets are used to enclose the list of words that are to be repeated. You can get guidance about how the text word corresponding to a particular block is meant to be used by clicking on that block, which you can ﬁnd on the left hand side of the Text Language Workspace. For example if you click on the “repeat” block the following text will appear in the Command Center:

repeat 10 [ WHATEVER ] In this message “WHATEVER” is meant as a place holder for the list of commands that you want repeated.

Other Examples

Plug in a touch sensor and a sound box and type:

waituntil [touch?] playsound 23

You should here a “meow” when you press the touch sensor on the touch sensor.

If you type: forever [waituntil [touch?] playsound 23] you should now hear the “meow” each time you press the touch sensor. In these last two examples you will need to make sure you type the square brackets in the proper places.

Plug in a display and type: display 7 * 9 + 6

The Text language uses parentheses to determine the order of in which things are done. Compare the above result to what you get if you type:

display 7 * (9 + 6)

1

Exceptions to this rule occur for the cases of the if and ifelse words; since the text word does not include “then”. For a complete list of the blocks and corresponding text words, see the Summary of Text Language Words chart at the end of this section.

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Procedures

You can “teach” your Cricket to understand new words by deﬁning procedures in the Procedures Area of the Text Language Workspace. Procedures are deﬁned using the following general form:

to procedure-name procedure-body end

The procedure deﬁnition starts with the keyword to, followed by the name of the procedure. Next comes the body of the procedure, which is a list of words that describe what the procedure is to do. The keyword end is used to complete the procedure deﬁnition.

For example, in the Procedure Area type:

to chirp-twice chirp wait 5 chirp end

You’ve now taught your Cricket a new word; if you type the word chirp–twice in the Command Center, the Cricket will chirp twice.

Procedures with Inputs and Outputs

You can create procedures that take inputs or produce an output. For example, you can create a procedure named chirps that takes an input that is used as the counter in a repeat loop. Note that the name of the input must begin with a colon.:

to chirps :num repeat :num [chirp wait 5] end

Typing

chirps 10

in the Command Center will cause the Cricket to chirp 10 times.

You can create a procedure that takes two inputs that will determine both the number of chirps and the duration of the pause between chirps:

to chirps2 :num :pause repeat :num [chirp wait :pause] end

Typing chirps2 10 3 in the Command Center will cause the Cricket to chirp 10 times, with a pause of 3 tenths of a second between chirps.

Procedures may return values using the output command. For example, you can deﬁne a procedure called half by:

to half output brightness / 2 end

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37

Then, with a display and a light sensor plugged in, try typing in the Command Center:

display half

Or, you can deﬁne a procedure called dark? that returns a true of false result:

to dark? output (brightness < 20) end

Now if try typing in the Command Center:

forever [if dark? [chirp]]

your Cricket should chirp when it is dark enough.

Make Your Own Blocks

You can use the Text Language to make different kinds of blocks, which you can then use to build programs in the PicoBlocks Workspace. This feature allows you to continue doing much of your programming using the Blocks Language, with the Text Language being used as a supplement when its advanced features are needed.

New blocks are deﬁned by typing in the Procedures Area. The block deﬁnitions begin with the keyword

block chirp1 chirp wait 3 chirp end

block. For example:

chirp1

Makes a block that chirps twice.

Blocks that you have deﬁned will automatically be created and placed in the “My Blocks” area. You can create blocks with up to three inputs. For example, to create a block with one input:

block chirp2 :num repeat :num [chirp wait 3] end

chirp2

Makes a block that chirps a number of times.

To create a block with two inputs:

block chirp3 :num :pause repeat :num [chirp wait :pause] end

chirp3

Makes a block that chirps a number of times, with the ability to vary the length of the pause between chirps.

When you deﬁne a block that outputs a number, PicoBlocks will automatically create a number–shaped reporter block:

block bright2 output 2 * brightness end

Reports a number twice as big as the brightness

bright2

measured by the light sensor.

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Use the keyword bblock when you want to make a block that outputs the result of a true/ false condition:

bblock dark? output brightness < 10 end

dark?

Using Tags in the Text Language

PicoBlocks “tags” are used when you are plugging in more than one of the same kind of part, two lights or two motors for example, and you want these parts to act differently. (See the previous section on Tags on pages 10 and 11.) In programs written in the Text Language, a word without a tag will address all parts of the same type. For example, if two lights are plugged into your Cricket, the command

setlightcolor 90 will turn both lights blue.

If you want to refer only to the light plugged into the

port, add a period to the end of the

word, without a space:

setlightcolor. 90

Similarly, to refer only to the light plugged into the port, add two periods to the end of the word, without spaces:

setlightcolor.. 90

To refer only to the light plugged into the port, add a period and a colon to the end of the word, without spaces:

setlightcolor.: 90

To refer only to the light plugged into the port just add two colons to the end of the word, without spaces:

setlightcolor:: 90

This method of tagging text words will work with other words2 . For example

display.: 57

will display the number 57 on a display plugged into the port and

forever [if touch?: [chirp]]

will cause the Cricket to chirp if a touch sensor that is plugged into the port is pressed.

Global Variables

In the “My Blocks” tab you will ﬁnd blocks for storing numbers in two different “global variables” called box1 and box2. In the Text Language you can use the keyword global: to create up to ﬁve additional global variables. For example, by including the line:

global: times, pause

2

Note: Tags will not work with words related to the sound box.

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39

in the Procedures Area you will create two new global variables called times and pause. Now, try typing the following in the command center:

storeintimes 5 storeinpause 3 repeat times [chirp wait pause]

The Cricket should chirp 5 times, with pauses of 3 tenths of a second between chirps.

If you click on the My Blocks tab you will also ﬁnd that new blocks corresponding to the new variables times and pause have been created.

Local Variables

The word make allows you to change the value of an input to a procedure. For example, if you deﬁne a procedure called rainbow by:

to rainbow :a repeat 30 [setlightcolor :a make “a :a + 1 wait 2] end

then, with a light plugged into your Cricket, typing

rainbow 20

in the Command Center will cause colors 20 through 49 to ﬂash.

Variables of this kind are called “local variables” because they are only available for use by the procedure in which they are deﬁned. Because PicoBlocks has a very limited number of global variables (7), local variables can be helpful because they do not use any of the global variable slots.

Tool Not Available in the Text Language

The “second wand” is not available in the Text Language.

Summary of Text Language Words

The following table shows the text word that corresponds to each PicoBlocks block and gives an example of how the word can be used.

Light

Block Word Example Usage

setlight

color

setlight power

light

off

setlightcolor

setlightpower

lightoff lightoff

number

Setlightcolor takes an input from 0 to 100.

setlightcolor 70

The light changes to cyan and turns on. Setlightpower takes an input from 0 to

100.

setlightpower 50

The light turns on at half power.

The light turns off.

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Light

Block Word Example Usage

display

number

Displays a value on the digit display:

display 709

The display shows the number 709. Sets the color of the light. Setrgb takes 3 inputs (red,

Text

only

setrgb

number

number number

green, and blue), each with a range from 0 to 100. The three inputs mix to give one particular light color.

setrgb 0 100 100 The light turns cyan.

Sound

Block Word Example Usage

chirp

note

play

sound

set

inst

set

tempo

set

volume

In addition to the blocks above can add your own blocks to the Sound tab by creating melodies and/or rhythms in their respective editors. The melody or rhythm name becomes a text word that you can use.

chirp chirp wait 3 chirp

The Cricket chirps twice.

Note takes two inputs. The ﬁrst input (a number between 0 and 100) determines the pitch of the note

note

number number

and the second input determines the duration of the note (in tenths of a second).

note 36 5

The sound box plays a note for half a second. Plays a sound on the sound board. Playsound takes

playsound

number

any number between 0 and 100. There are 24 built-in sounds. Playsound repeats the list in sequence for numbers greater than 24.

playsound 24 The sound box meows.

Sets the instrument for the next note, or melody to be

setinstrument

number

played on the sound board. Setinstrument takes any number between 0 and 100:

setinstrument 4 note 36 5

The sound box plays violin note. Sets the tempo at which the next rhythm or melody

will be played on the sound board. Settempo takes any

settempo

number

number between 0 -lowest pace- and 100 -fastest pace.

settempo 50 melody1

The sound box plays a melody at the standard tempo.

setvolume

number

Sets the volume at which the next note, sound, rhythm or melody will be played on the sound board. Setvolume takes any number between 0 -lowest volume- and 100 -highest volume:

setvolume 30 playsound 24 setvolume 100 playsound 24

The sound box meows softly, then loudly.

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41

Action

Block Word Example Usage

motor

on

motor

onfor

reverse

this way

set

power

text only

motor

off

that

way

motoron motoroff

motoronfor

reverse

thisway thatway

setpower

brake

coast

number

Turns a motor on or off.

motoron wait 10 motoroff

The motor spins for 1 second. Turns the motor on for a set period of time (in

tenths of a second).

motoronfor 10

The motor spins for 1 second. Change the direction in which the motor spins.

repeat 6 [motoronfor 3 reverse]

The motor wiggles back and forth. Set the motor to spin in a speciﬁc direction.

thisway motoronfor 10 thatway motoronfor 10

The motor spins one way for 1 second, then the other way for 1 second.

Setpower takes an input from 0 to 100. setpower 100 motoronfor 10

The motor spins quickly.

setpower 30 motoronfor 10

The motor spins slowly. Causes the motor to stop immediately. This is

slightly different from short brake followed by a coast.

motoron wait 10 brake

The motor spins for 1 second, then immediately comes to rest.

Turns off the power to the motor but does not brake it, so that the motor slowly comes to rest.

motoron wait 10 coast

The motor spins for 1 second, then slowly comes to rest.

motoroff, which does a

Block Word Example Usage

touch?

brightness

touch?

brightness

Sensors

Reports true if the touch sensor is pressed.

waituntil [touch?] chirp

The Cricket waits until the touch sensor is pressed before chirping.

Reports the value measured by the light sensor as a number from 0 to 100.

forever [display brightness wait 1]

The display shows, and continually updates, the light level measured by the light sensor.

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Sensors

Block Word Example Usage

loud?

loudness

connected?

resistance

text only

beamIR

loud?

loudness

connected?

resistance

rawresistance

rawrange

beamir

number

Reports true (the number 1) if the value measured by the sound sensor is greater than 15.

waituntil [loud?] chirp

The Cricket will chirp after the sound sensor detects a loud sound.

Reports the value measured by the sound sensor as a number from 0 to 100.

forever [display loudness]

The display shows, and continually updates, the sound level measured by the sound sensor.

Reports true if the value measured by the resistance sensor is less than 50.

waituntil [connected?] chirp

The Cricket waits until the alligator clips on the resistance sensor connect before chirping.

Reports a number from 0 to 100. The sliders are not available in text language.

forever [display resistance wait 1]

The display shows, and continually updates, the electrical resistance measured by the resistance sensor.

Reports the value measure by the resistance sensor as a number between 0 and 1023; rawresistance provides ﬁner resolution than resistance.

forever [display rawresistance wait 1]

The display shows, and continually updates, the electrical resistance measured by the resistance sensor on a scale of 0 to 1023. (Numbers of 1000 or greater appear as dashes.)

Rawrange is used to adjust the sensitivity of the resistance sensor. It takes as an input either the number 0 , 1, or 2. An input of 0 results in the highest sensitivity and should be used when measuring resistances of 1000 ohms or less. An input of 1 is medium sensitivity and is the default setting. It works best for resistances of about 10,000 ohms. 2 is the lowest sensitivity and should be used to measure resistances of 100,000 ohms or more.

rawrange 0 display rawresistance

Beams a number from the Cricket’s infrared transmitter.

beamir 4

newIR?

newir?

Reports true (the number 1) if the Cricket’s infrared receiver has received a new value.

waituntil [newir?] chirp

The Cricket chirps when a new number is beamed to it.

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43

Sensors

Block Word Example Usage

Reports the value of the most recent number beamed to the Cricket.

IR

reset

timer

ir

resettimer

timer

to test waituntil [newir?] if ir = 10 [chirp] end

The Cricket chirps if the number beamed to it is equal to 10. Resets to zero the value of the Cricket’s internal timer. See next

example.

Reports the Cricket’s timer value. Timer measures time in hundreths of a second.

to test resettimer chirp waituntil [touch?] display timer end

The display shows the amount of time that has elapsed between when the Cricket chirps and when the touch sensor is pressed.

Flow

Block Word Example Usage

Waits a certain amount of time (in tenths of a

wait

text only

waituntil

forever

wait

mwait

no-op

waituntil [

forever [

number

list

condition

]

second).

chirp wait 10 chirp

The Cricket pauses for a second between the two chirps.

Waits a certain amount of time (in milliseconds).

setlightcolor 20 mwait 10 lightoff

The light ﬂashes very brieﬂy. Does nothing for about 40 microseconds.

repeat 10 [no-op]

The Cricket waits for 400 microseconds. Waits until the condition is true.

]

waituntil [touch?] chirp

The Cricket waits until you press the touch sensor before chirping.

Repeats a list of instructions forever.

forever [chirp wait 3]

The Cricket chirps continuously.

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Flow

Block Word Example Usage

repeat

if

then else

stopall

stop

stack

then

repeat [

if [

ifelse [ [

stopall

stopstack

number

condition

list

condition list1 list2

list

]

] ]

Repeats a list of instructions a set number of times.

repeat 5 [chirp wait 2]

The Cricket chirps ﬁve times. Runs a list of instructions if a certain condition is

met.

forever [if touch? [chirp wait 1] ]

The Cricket chirps if you press the touch sensor and is quiet if you do not press it.

Runs the ﬁrst list of instructions if a certain condition is met and the second list if it is not.

to test forever [ifelse touch? [setlightcolor random 0 99] [lightoff] ] end

The light ﬂashes random colors if you press the touch sensor and turns off if it you do not press it.

Stops everything: programs, motors, etc. Stopall is equivalent to pressing the button on the Cricket.

to test motoron forever [if touch? [stopall] setlightcolor random 0 99] end

The lights and motors stop when you press the button.

Terminates execution of a procedure, returning control to the calling procedure.

to test forever [if touch? [stopstack] setlightcolor random 0 99] end

There is no need for spacers in the text language.

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45

Numbers

Block Word Example Usage

Reports a number. Numbers in PicoBlocks are

number

+

-

x

/

text only

r a n d o m

number

%

random

number

+

number

-

number

*

number

/

number

limited to integers between -32768 and +32767.

display 7 The display shows the number 7.

Reports the sum of two numbers.

display 7 + 4

The display shows the number 11. Reports the difference of two numbers.

display 7 - 4

The display shows the number 3 Reports the product of two numbers.

display 7 * 4

The display shows the number 28. Reports the quotient of two numbers, rounded

down to the nearest integer.

display 7 / 4

The display shows the number 1. Reports the remainder when two numbers are

divided.

display 7 % 4

The display shows the number 3. Report a random number, the two inputs

determining the lower and upper limits

display random 0 10

The display shows a random number from 0 to 10. Reports true (the number 1) if the value of the ﬁrst

input is greater than the value of the second input.

to test

>

number

>

number

forever [if brightness > 30 [chirp]] end

The Cricket chirps if the light sensor measures a value greater than 30.

Reports true (the number 1) if the value of the ﬁrst input is less than the value of the second input.

to test

<

number

<

number

forever [if brightness < 30 [chirp]] end

The Cricket chirps if the light sensor measures a value less than 30.

Reports true (the number 1) if the value of the ﬁrst input is equal the value of the second input.

=

number

=

number

forever [if brightness = 30 [chirp]]

The Cricket chirps if the light sensor measures a value exactly equal to 30.

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Numbers

Block Word Example Usage

Reports true (the number 1) if the ﬁrst and second conditions are both true.

and

not

or

condition

not

condition

and

or

condition

to test forever [if (brightness < 30) and touch? [chirp]] end

The Cricket chirps if the light sensor measures a value less than 30

and

the touch sensor is also

pressed Reports true (the number 1) if the ﬁrst or the second

conditions are both true.

to test forever [if (brightness < 30) or touch? [chirp]] end

The Cricket chirps if the light sensor measures a value less than 30 or the touch sensor is pressed

Reports true (the number 1) if the result of the condition is false (number 0).

to test forever [if not touch? [chirp]] end

The Cricket chirps if the touch sensor is

not

pressed.

My Blocks

Block Word Example Usage

store in

box1

text only

block

block-denition

end

storeinbox1

box1

global:

make

name

number

“name value

You can use the text language to make your own blocks. (See section Make Your Own Blocks above.)

Stores a number in the global variable called box1.

storeinbox1 57 display box1

The display shows the number 57. Reports the number stored in the global variable

called box1.

storeinbox1 57

You can use the text language to create new global variables. (See section Global Variable above.)

Make allows you to change the value of a local variable. (See section Local Variables above.)

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47

Common Error Messages

Error Message Explanation

The Beamer cannot see the Cricket

Can’t ﬁnd the Beamer PicoBlocks wasn’t able to open the communication port.

Can’t save an empty score You tried to export a melody or rhythm that is empty.

Can’t use ____ as a name

The Beamer is sending, but no Cricket is responding.

Solution: Make sure the Cricket is turned on, and that the Cricket and the Beamer are facing each other. For more information, see

www.picocricket.com/troubleshooting

Solution: Make sure the Beamer is properly connected to your computer. If you are using Windows, make sure only one copy of PicoBlocks is running. For more information, see:

www.picocricket.com/support

Solution: Make sure the block contains notes, then click Export again.

PicoBlocks does not allow that word as a name. Numbers, names starting with % or [ , and existing words are considered invalid.

Solution: Type another name.

Communication problem

There was a communication problem while PicoBlocks was downloading data to your Cricket.

Solution: Make sure that the Beamer and the Cricket are facing each other, then try again. If the Cricket’s yellow antenna lights keep ﬂashing even when you are not downloading, the Cricket is probably receiving infrared interference from a monitor or other device. Shield the Cricket from the monitor. For more information, see www.picocricket.com/troubleshooting

Missing input to _______ One (or more) of the blocks requires input.

Solution: Check that every block has something attached on its right side when required. (You can tell by the shape of a block whether it takes an input.)

For example, display needs a number (or other value) attached as an input:

display

100

Repeat requires a number value at the top right. It also requires plus one or more blocks under its “arm” to repeat:

repeat

10

chirp

Tip: To check if a block needs inputs, click on the block with the

?

Help tool

?

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PicoBlocks - Reference

Error Message Explanation

I don’t know how to ______

PicoBlocks tried to run a name that doesn’t exist.

Solution: If you name a stack, then PicoBlocks creates a block with that name. To run the block, you need to keep the named stack in the Workspace, so PicoBlocks knows what to do.

The name ____ already exists

There is already an existing block with the same name.

Solution: Type another name.

Number block doesn’t like

You typed an invalid character in

_____

Solution: Type only numbers.

Project contains too many

Your project contains too many blocks.

blocks

Solution: Delete all stacks, melodies and rhythms that are not being used.

Too many blocks in the stack The stack contains too many blocks (and uses up too much

memory).

Solution: Use a repeat to do more with fewer blocks. Or, place a

on the top of the stack, and click on it

to type in a name.

Too many music blocks: Limit of 24

You have made more than the maximum number of music blocks. The maximum number of melodies and rhythms is 24 blocks.

Solution: Delete some of the melody or rhythm blocks so that the project has no more than 24 total.

Too many notes for one music

The current melody or rhythm is too long.

block

Solution: Divide the melody or rhythm into two blocks. To do this, ﬁrst copy the current music block. In this block, delete the second half of the notes. In the other block, delete the ﬁrst half of the notes. Now you can use these two blocks together to play the entire sequence.

waituntil needs input The waituntil block needs an input block that ﬁts.

Solution: Attach a block that ﬁts onto the right side of the waituntil block.

Examples:

waituntil

loud?

or

waituntil

brightness

>

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49

Error Message Explanation

You can’t copy an empty music block

You can’t name a stack ______

You don’t say what to do with ________

You tried to copy a melody or rhythm that is empty.

Solution: Add notes, then copy the block.

The name typed on the contains invalid characters. It cannot contain the following characters:. % “ + - * / ] [ or a space. Numbers can only be used in combination with letters.

Solution: Type letters on the PicoBlocks tried to run a block that returns a value, but

there was no block attached to receive that value.

Solution: Attach a block that will ﬁt that shape (and receive the value). For example:

waituntil

touch?

Text-Only Error Messages

The following error messages only appear when using the PicoBlocks Text Language.

Error Message Explanation

_______: a block can’t have more than 3 inputs

______ has no value

_______: output block can only have 1 input

You can’t make a block with more than 3 inputs.

Solution: Store the other values as global variables, and use the names of these variables in your program. For more information, see Global Variables in the PicoBlocks Text Language section of this reference guide.

PicoBlocks could not ﬁnd a value for the speciﬁed name.

Solution: In the Text Area, check that you have correctly typed the name of the input. Inputs should have a colon preceding them, but global variables should not.

A block that outputs can only have 1 input.

Solution: Store the other values as global variables, and use the names of these variables in your program. For more information, see Global Variables in the PicoBlocks Text Language section of this reference guide.

() error

misplaced )

A parenthesis is missing or misplaced.

Solution: Check that there are an equal number of open and closed parenthesis ( ), and that they are correctly placed.

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Error Message Explanation

Can’t name a global _______

Can’t use _____ as name of an input

Missing [ Missing ]

Missing name after

to

Missing name after block Missing name after bblock

You need to type in a different name for the global variable.

Solution: Use only letters and numbers as names for global variables. See Global Variables in the PicoBlocks Text Language section of this reference guide for more information.

PicoBlocks doesn’t like numbers as the name of an input.

Solution: You need to type in a different name for the input. Avoid using numbers as input. Also, make sure to put a colon before the name of the input.

For example:

block mydance :turns repeat :turns [motoronfor 10 reverse] end

There is a missing bracket: ] or [

Solution: Make sure there are an equal number of open and closed brackets.

Solution: The words to, block, and bblock need to be followed by a valid name. For example:

block mylights setlightcolor 60 wait 10 lightoff end

No output from _____ The word or block indicated does not provide output.

Solution: Make sure every block has something attached on its right side when required. See the PicoBlocks Text Language section for more on how to use output.

Too many globals

There are too many global variables in the project. The maximum number of variables is 7 (including box1 and box2).

Solution: Delete some of the global variables so that the project has no more than 7 total.

waituntil needs a list as input. waituntil needs a list as input.

Solution: Add a list in brackets after waituntil

For example:

waituntil [touch?] chirp

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Error Message Explanation

make needs a local variable Make needs to be followed by the name for a local variable.

Solution: Check that the word after make has a quotation mark before it, and is a local variable.

For example:

block fastlight :n setlightcolor :n make “n :n / 10 wait :n lightoff end

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PicoBlocks - Reference

PICO PicoCricket Reference Manual

Specifications and Main Features

Frequently Asked Questions

User Manual