Morse Tutor
Board
User Manual v1.1
www.k1el.com
K1EL Morse Tutor Board MTB
Morse Tutor Board (MTB) Features
• Keyer speed range: 5 - 99 WPM • Integrated Touch Paddle and Pushbuttons
• Touch sensitivity calibration function • 34 easy to use commands
• Dynamically allocated message memory • Supply Voltage Monitor
• Keying Modes: Bug, Ultimatic, Iambic A or B • Serial Number Generation
• Rotary Encoder Speed control • Adjustable Letter Spacing: 25 to 75%
• Adjustable Weighting: 25 to 75 % • Automatic letter space mode (Autospace)
• Paddle swap command • Sidetone Output: On board speaker
• Continuously adjustable Sidetone frequency • Optional Key Output: Open collector (60V @120mA)
• Four Push-button user interface • Battery holder for three AAA cells
• Two User Configurations each with callsign • Backspace supported on message entry
• Low Power Consumption: 2 mA idle, 70 uA off • Power on/off by pressing rotary encoder.
• Non-Volatile Message Memory: 232 letters in 10 • Easy access Rx and Tx practice modes
Slots, dual banked, with embedded commands. • Multiple MTBs can be networked together
• Non-Slip Rubber Feet • Message stacking
• Beacon: Programmable interval: 1 to 99 seconds • Board Dimensions: 4.0” by 3.25”
Morse Tutor Description (MTB)
The MTB is designed to be a low cost educational platform for learnin g and practicing Morse code.
Everything the student needs is on the board including touch pad inputs. Optimal touch paddle sensitivity is
maintained by an auto-calibration algorithm. The MTB is implemented in a Microchip PIC16F1825
microcontroller and utilizes a special version of the K1EL K16 keyer core which provides a wide range of
features. Setup commands are directly entered on the paddles in Morse code. All settings and messages
are stored in nonvolatile memory so that they are preserved when the keyer is turned off. The K16 keyer
core has many original features not found in other keyers:
• Supply Voltage Monitoring
The MTB has a unique feature that is useful in battery powered applications. It can accurately monitor its
supply voltage and provide an indication when battery voltage is low. Normally the MTB will respond with an
R when entering command mode. If the battery voltage is approaching the minimum operating limit, it will
respond with an L instead. This tells the operator that the batteries need to be replaced. The actual supply
voltage can be read out in Morse by using the V command in the extended command set. (Page 16). The
keyer will continue to operate until the battery voltage falls to approx. 2.7V.
• Dual User Configuration
The MTB provides storage for two complete configuration setups. For example, one setup could be used for
contesting while the other for casual operating. Or, when two operators share the same keyer, each user
can have their own setup profile. The extended command U is provided to select one configuration or the
other. All MTB settings are included in each profile including a stored callsign. (Page 16)
• Dual Message Banks
The MTB has two message banks of five slots plus two callsign slots. Total message storage is 232 bytes.
While this does not seem like a lot of message space, since the MTB dynamically allocates message
storage in memory, it turns out to be more than adequate for most users. It is very easy to swap message
banks with the E command. This is the shortest command sequence and allows you to swap banks quickly.
There is also a buffered message command /E that swaps message banks within a message. (Page 19)
• Stored Callsigns
Two special memory slots are provided to store a callsign for two users. These callsigns are programmed by
using the callsign load command in the extended command set. A callsign is embedded in a message b y
using the /M buffered command. The callsign slot works like any other message slot; you can call other
messages and embed commands, (Page 19)
• Wide range of embedded message commands
Please refer to the list on page 19.
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K1EL Morse Tutor Board MTB
• Sidetone Frequency
The MTB sidetone can be set to any frequency between 300 Hz and 200 0Hz. (Z command, page 15)
• Fast Message Interruption
The MTB will stop a message immediately upon pad dle press, stopping in mid-letter if need be.
• Practice Modes
Many practice options are supported. The user can select practice content by letter group so that easier
letters can be mastered first followed by progressively more difficult groups. A very good random letter
generator is provided which generates a varied, ever changing letter order. (G & P commands, Page 16)
• Message Stacking
Up to 10 messages can be queued to be sent in the order requested. Just press a sequence of up to 10
message pads and the MTB will play them in order.
• Simplified Beacon Formatting
This message is all that is required to setup a repeating 15 second beacon: /B15 K1EL BCON
• Easy Beacon
Any message slot can be turned into a beacon without having to add the special /B embedded command.
The B command allows ‘on the fly’ beaconing without embedded commands. (Page 13 )
• Dit/Dah Ratio Control
The timing of dits vs. dahs can be customized. A ratio of 1:3 is standard but this can be altered to suit
different tastes. (Y command, Page 15).
• Improved Cut Number Selection
The MTB allows serial number cuts to be used for 0 and/or 9. (Extended commands N&T Page 16)
• Tuning Duty Cycle Selection
Tune can be set to generate either a 50% or 100% key down duty cycle. (V command, Page 15)
• Contest Word Spacing
The MTB allows a shorter inter-word spacing to be selected to speed up exchanges during contests.
Standard word spacing is 7 dits while contest mode word spacing is 6 dits. (Extended C comman d, Page 16)
• Full Time Speed Control
The MTB responds to speed encoder changes without delay, even while sending messages.
• Speed Control Range Setting
The upper and lower limit of the speed control can be set by command. Two values are entered the lowest
speed control setting followed by the highest speed control setting. (R command, Page 16)
• Command Response Time Adjustment
The MTB will enter command mode when the encoder pushbutton is pressed down for about 2 seconds.
This may be too long for some operators so it can be shortened to 1.3 seconds. (F command, Page 16)
• Touch Paddle Adjustment
The MTB scans and adjusts paddle sensitivity automatically based on current conditions, however, due to
process variations in PIC microcontrollers, a baseline calibration must be run once when the kit is complete.
See page 10 for the procedure description.
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K1EL Morse Tutor Board MTB
Morse Tutor Functional Block Diagram
Figure 1 is a block diagram of the MTB. As shown, there are five touch pads, a sidetone speaker, rotary
encoder speed control/pushbutton, and an RCA keying port that can connect to other MTBs in a network
configuration or to key a transceiver/transmitter. The pushbutton on the encoder is dual purpose; press and
hold to enter commands, or a quick press to play a message. A longer press will cycle the keyer’s power.
Touch keyer paddles and message pushbuttons are integrated into the MTB circuit board which all ows very
compact layout. The board is completely self contained, running on three standard AAA batteries. No other
accessories are required to use the MTB.
Figure 1 – Morse Tutor Block Diagram
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K1EL Morse Tutor Board MTB
Morse Tutor Board Kit
The MTB keyer kit consists of a single board with all through-hole components for easy assembly. It’s a
good idea to read through the assembly instructions before starting. Please follow the steps in the order
presented for best results. Even if you are an experienced builder, we highly recommend reviewing the
appendices A, B, and C at the end of this document for helpful assembly hints.
Morse Tutor Board Assembly
Morse Tutor Parts Inventory
U1 – K16 14 pin DIP IC (16F1825)
Q1,2 – PN2222A NPN transistor
R2 – 22Ω ¼ watt (red red black)
R1,3 – 2.7KΩ ¼ watt (red violet red)
R4,5 – 330Ω ¼ watt (orange orange brown)
C1,5 – .1 μF ceramic capacitor 104
C2,3,4 – .01 uF ceramic capacitor 103
D1 – Green LED
B1 – Battery Holder (3xAAA)
SP1 – Mini speaker
J1 – RCA keying connector
RE1 – Rotary Encoder
1 pc – 14 Pin DIP Socket
1 pc – Morse Tutor PC board
JMP/HDR – 2 pin power jumper set
Misc – 4 rubber feet, 2 foam tape squares
Figure 2 – Morse Tutor PC Board (MTB) before assembly
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K1EL Morse Tutor Board MTB
Figure 3 - MTB component identification
Start by attaching the four stick-on rubber feet to the bottom side of the board:
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Figure 4 – Rubber feet in place
K1EL Morse Tutor Board MTB
Install and solder all five ¼ watt resistors, their color codes are listed in the parts inventory on page 5. We
recommend verifying resistor values with an ohmmeter.
Install and solder two .1uF and three .01 uF capacitors.
Figure 5 – Resistors and capacitors installed
Install the 14 pin DIP socket; orient the notch in the socket as shown in Fig. 6. Next, install transistors Q1
and Q2, with the flat sides lining up with the silkscreen. Now install the speaker with the silver dot facing C2.
The LED must be installed with flat side as shown. If you are not sure which side that is, note that one of the
leads on the LED is slightly longer than the other, an arrow on figure 6 points to where that should go.
Install both two pin headers; this is a little tricky since the jumper tends to fall out while you are soldering
them. Place a black plastic jumper on each header to give you something to hold on to. Don’t use a lot of
heat as that can melt the jumper. After soldering, be sure to remove the plastic jumpers.
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K1EL Morse Tutor Board MTB
Figure 6 – Socket, 2 pin headers, Q1, Q2, speaker, and LED installed
Snap the RCA connector into place and be sure it is fully seated into the board before soldering. It will take
some extra heat to solder this part in so don’t rush it. Be careful here since the body of the RCA jack will get
extremely hot while it’s being soldered, so don’t touch and avoid a painful burn. Once the connector is
snapped in place it will stay there while you solder it.
Now install the rotary encoder. Again, insure that the encoder is fully seated and its bottom flush with the
surface of the PC board before soldering. You may have to tweak one or more of the five encoder leads in
order to get the part to fit in the PCB holes. Make sure each pin goes through the board before soldering.
Be sure to remove the protective film cover from the speaker so you will be able to hear the sidetone loud
and clear.
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Figure 7 – RCA jack and Encoder installed
K1EL Morse Tutor Board MTB
Install the battery holder. Two strips of double sided tape hold the holder to the PC board. Peel off the
protective film from each tape and press the holder in place, align the holder with the board’s silk scre en.
Figure 8 – Two sided foam pieces on bottom of battery holder.
Install U1 in its socket, pin 1 (the one closest to the circular indentation) goes to the lower right. You may
need to straighten the IC’s leads as shown in the picture on the left. Push just enough to bend but not crush
the leads, using two hands helps. The silver dot on the IC signifies that the part has been programmed.
Figure 9 – Straighten leads on U1, then install in socket
The last task is pushing the plastic knob on the encoder shaft. The flat of the encoder shaft has to line up
with the flat of the knob. You will have to push pretty hard to get this to go on all the way. We recommend
putting something under the encoder when pushing the knob in place to avoid flex ing the board and possibly
breaking copper traces.
This completes the assembly of the MTB board. Before continuing, carefully re-inspect your work. Please
check that Q1, Q2, and U1 are placed correctly and that all parts were installed. Make sure that all solder
connections have been made and that there are no solder shorts between pads. The completed assembly is
shown on page 10.
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