10 exciting solar projects which you can actually use.
Projects featured in this box:
Solar-Powered LED ........................................................................... As long as the sun shines, the LED will light (pag.8)
Flashing Solar LED
Solar-Powered Cricket......................................... ...................... As long as the sun shines, the cricket will chirp (pag.12)
Simple Solar Battery Charger
Solar Battery C harger with ‘Charge’ Indicator
Solar Musical Instrument
IR Remote Control Tester
Solar Garden Light
Solar Motion Detector / Beam Break Detector
Solar-Powered ‘Alarm Armed’ LED
Attention: All projects require direct sunlight or a strong incandescent lightbulb (min 60W). Fluorescent, energ y saving, led
and certain halogen lightsources are not suited or will not give satisfactory results.
.................................. ..................... Free energy to keep your batteries in shape (pag.14)
................... An LED turns on when the batteries are charging (pag.16)
.................................................................. ............................. More light = higher note (pag.18)
............................................................... ............................ ‘Listen’ to your IR remote (pag.20)
............................... ................... LED turns on at dusk and turns off at dawn, fully automatic (pag.22)
.............. ................... Announce wanted or unw anted guests (pag.24)
................... ................... Charges during the day, scares burglars at night (pag.26)
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Parts supplied with this kit:
4V / 30mA solar cell
This device will convert sunlight into electricity,
which we will use in all projects. More light means
more electricity. Point the black surface towards the
sun.
Breadboard
Will hold all your experiments. The white lines
show how the holes are electrically connected
with eachother
4
E1
(Velleman part# YH-39X35)
SOLAR C ELL
(Velleman part# SDAD102)
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d
e
R
k
c
a
l
B
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Wire jumper Ultrabright yellow & red LED
Just a piece of bare wire to
Flat side
Shortest leg = (-)
The yellow & red LED provide a lot of light and require a very low
current to operate. Watch the polarity !
connect two points in a circuit.
(Velleman part# L-5YAC & L-7104LID)
Resistors
R1
100
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Various resistor values are supplied. They serve as
current limiters or as voltage dividers. Resistors do
not have a polarity. Resistors values are indicated
by means of coloured rings. The unit of resistance is
called ’Ohm’.
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Diode
Diodes allow the current to flow in only one direction, from
(+) to (–). Current flow in the opposite direction is blocked.
(Vellem an part# BAT85)
A special case: Zener diodes
Zener diodes allow the current to
flow from (+) to (-), as regular diodes
do. If you invert the polarity, they
drop a certain voltage, which can be
found on the body of the zener
diode, e.g. 2V4= 2.4V
Battery holder
d
e
R
Holder for two AAA rechargeable batteries. Mind the polarity
(Velleman part# BH421A)
6
k
c
a
l
B
(Velleman part# ZA2V4)
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Page 7
Transistors
A transistor is an amplification device. By means of a small
current, a much larger current is controlled. Transistors come in
E B C
C B E
two flavours, NPN and PNP-types, depending on the polarity. With
this kit, you receive a BC557 (PNP) transistor. A transistor has 3
pins: Base, Emitter and Collector.
Piezo speaker
Microcontroller (µC)
A programmable device which can perform various tasks.
We have pre-programmed it so that it will play musical notes or it
will generate the sound of a cricket. This device is has a polarity.
Watch the position of the notch.
(Velleman part# BC557B)
A piezo speaker converts an electric
signal into sound. Polarity is not
important
(Velleman part# TV1)
(Velleman part# VKEDU02)
Noir
Rouge
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Project 1: Solar Powered Led
As long as the sun shines, the led will light...
8
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Page 9
Required parts: Solar cell, 100 ohm resistor (brown black brown gold), yellow led
or ange
How it works: A closed circuit is
required to make the current flow.
Current flows from the (+) of the
solar cell trough resistor to the (+)
of the led and via the (-) of the led
back to the solar cell. On a sunny
day, the solar cell will generate 3..4
volts. The led only requires 2 volts
to operate. Resistor R1 converts
the excess voltage into (a little)
heat, hereby protecting the led from
damage.
Time to experiment:
What happens when you swap (+) and (-) of the led?
What happens when you replace the 100 ohm resistor with
a 47000 ohm resistor (yellow purple orange gold) ?
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R1
100
E1
SOLAR CELL
LD1
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Project 2: Solar Flashing Led
Solar powered attention grabber
µC
Jumper wire
10
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Page 11
Required parts: Solar cell, 100 ohm resistor (brown black brown gold), yellow led,
microcontroller (µC), wire jumper.
How it works: The controller
requires 2-5V to operate. This
voltage is supplied by the solar
panel. The microcontroller is
pre-programmed with software
that turns the output on and off
in a loop. The signal is output
via pin 4. When the output is
on, current flows via the led and
the resistor, hereby causing the
led to light.
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µC
SOLAR CELL
R1
10 0
LD1
2
VD D
5
GP0 /ICS PDAT
3
GP2 /T0C LKI/FO SC4
4
GP1/ICSPCLK
VSS
7
IC1
PIC10F200-I/PG
GP3/MCLR/VPP
8
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Project 3: Solar Powered Cricket
As long as the sun shines, the circket will chirp...
Jumper wire
µC
Jumper wire
12
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Page 13
Required parts: Solar cell, microcontroller (µC), piezo sounder, wire jumpers
How it works: The controller
requires 2-5V to operate. This
voltage is supplied by the solar
panel. The microcontroller is pre
-programmed with software that
generates a realistic cricket
chirp. The chirp signal is output
via pin 4. The electrical signal is
converted to sound via the piezo
speaker.
Hint: Use this circuit as a
wake-up-at-dawn alarm.
It will wake you at sunrise...
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µC
SOLAR CELL
+
5
3
4
BUZ 1
PIEZO
2
IC1
PI C10 F20 0-I/ PG
VD D
GP0 /I CSPDAT
GP2 /T 0CLKI /FO SC4
GP1 /I CSPCLK
GP3 /MCL R/VPP
VSS
7
8
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Project 4: Simple Solar Battery Charger
Free energy to keep your batteries in shape...
14
Insert two AAA 1.2V
rechargeable batteries*
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*Not included
Page 15
Required parts: Solar cell, BAT85 diode, battery holder for two AAA batteries, two AAA
1.2V rechargeable batteries.
How it works: As long as the
solar cell is exposed to light, a
BAT 8 5
current will flow from the solar cell
via the diode trough the batteries
and back to the solar cell. The
SOLAR CELL
charge current depends on the
amount of light that reaches the
solar cell. Max. current with the
supplied cell is 30mA.
A diode prevents discharge of the
batteries trough the solar cell
(e.g. at nighttime), as it only
allows the current to pass in one
direction.
How long does it take to fully charge the batteries?
Check the capacity of your batteries. You can find this
info printed on the battery. Usually, it is expressed in
mAh, e.g. 300mAh. Multiply by 1.2 = 360mAh.
Divide by 30mA = 12 hours
Twelve hours of bright sunlight are required to fully
charge the batteries (rule of thumb).
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Project 5: Solar Battery Charger With ‘charge’-Indicator
yellow led, battery holder for two AAA batteries, two AAA 1.2V rechargeable batteries.
How it works: When the sun shines, a current
flows from the (+) of the solar cell via the Emitter/
Base of the transistor trough the batteries and
back to the solar cell. This is the Base current,
indicated with the dotted line. In our example,
the Base current will also charge our batteries.
The fact that there is a current flowing between
Emitter and Base causes the transistor to turn on
and fully conduct, as if it were a switch. Hence,
a current can flow from the solar cell via the
transistor Emitter/Collector and resistor to the led
and back to the solar cell. This current causes
the led to light (solid line).
For advanced users:
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The led turns off when the batteries are removed. Why ?
In the simple battery charge circuit, there was a diode to
prevent discharging of the batteries in low light condition.
In this circuit, it has been omitted. Why ?
provides the supply voltage for the
microcontroller. Once it receives
2VDC it starts running its internal
program. The zener diode and the
470 ohm resistor make sure the
supply voltage of the controller
never goes beyond 2.4V, even in
bright sunlight. A too high voltage
can damage the device. The
voltage generated by the solar cell is
SOLAR CELL
also divided by two by means of two
equal resistors (4K7) and fed to the
analog input of the PIC. Even in
bright sunlight, the input r eceives no more than 4.5/2 = 2.25VDC.
The internal software ‘measures’ the voltage at the input and translates it to a variable audio frequency
(note). The piezo sounder converts the signal into sound. When the amount of light r eceived by the solar
cell changes, the voltage at the input of the controller will also change. The s ofware will notice this and
change the tone. With a bit of practic e, you could play a tune by waving your hand or a flashlight over the
solar cell.
IC1
2
PIC10F220
VD D
GP3 /MCL R/ VP P
VSS
7
8
3
ZD1
2V4
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Project 7: IR Remote Control Tester
‘Listen’ to your IR remote
PIC
+/- 5cm
20
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Page 21
Required parts: Solar cell, piezo sounder, IR remote control (option).
How it works: Solar cells are
sensitive to infrared light. When hit
by infrared light, they generate a
voltage, like they do with sunlight. IR
remote controls generate a beam of
infrared light when they are operated.
This beam of light is turned on and
off very fast by the internal
SOLAR CELL
electronics of the remote control.
The pattern generated by the on-off
transitions is different for each button
of the remote. This allows the
receiver to recognise each individual
button. In this circuit, the on-off
transistions are translated into sound
by the piezo sounder.
More fun:
Try ‘listening’ to different light sources such as
led lighting, fluorescent lighting, etc...
+
BUZ 1
PIEZO
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Project 8: Solar Garden Light
Led turns on at dusk and turns off at dawn, fully automatic
ohm resistor (yellow, purple, brown, gold), BAT85 diode, yellow led, battery holder for
two AAA batteries, two AAA 1.2V rechargeable batteries, jumper wire.
How it works: W h en t h e sun shin es, t he
voltage generated by the solar cell will be
higher than the voltage of the batteries, s o a
current will flow from the solar cell to the
batteries. This current will charge the
batteries. The BAT85 diode prevents
discharging of the batteries trough the solar
cell in low light conditions. The base of the
transistor is tied to ground (-) by means of
the 4K7 resistor. This c auses the transistor
to turn on and allows a current to flow from
the batteries trough the transistor, the led
and via 470 ohm resistor back to the
batteries. The led will turn on. However,
note that the base of the transistor is also
tied to the (+) of the solar cell, s o as long as
the sun shines, the base of the transistor is
kept high enough to prevent turn-on of the
transistor, s o the led remains off at daytime.
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SOLAR CELL
D1
Charge current
Led current
(only at night)
Base current (onl y at night)
R1
4K7
R2
47 0
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Project 9: Solar Motion Detector / Beam Break Detector
How it works: The solar cell provides the
supply voltage for the microcontroller. Once the
controller receives 2VDC it starts running its
internal program. The zener diode and the 470
ohm resistor make sure the supply voltage of
the controller never goes beyond 2.4V, even in
bright sunlight. A too high voltage can damage
the device. The voltage generated by the solar
cell is also divided by two by means of two
equal resistors (4K7) and fed to the analog
input of the controller.
Even in bright sunlight, the input receives no
more than 4.5/2 = 2.25VDC.
The internal software ‘measures’ the voltage at
the input and compares it to the previous level.
When it detects a sudden change (i.e. W hen
the beam is interrupted or someone casts a
shadow on the solar cell ), it generates a sound
trough the piezo.
SOLAR CELL
R1
4K7
R2
4K7
R3
47 0
5
GP 0/I CSP DAT
BUZ1
PIEZO
GP2 /T 0CLKI /FO SC4
4
GP1/ICSPCLK
+
IC1
2
PIC10F220
VD D
GP3/MCLR/VPP
VSS
7
4
P
P
4
8
3
4
ZD1
2V4
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Project 10: Solar Powered ‘Alarm armed’-led
Charges during the day, scares burglars at night
Jumper wire
4K7
Insert two AAA 1.2V
rechargeable batteries*
26
PIC
Jumper wire
µC
100
*Not included
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Page 27
Required parts: Solar cell, microcontroller (µC), 4K7 resistor (yellow, purple, red, gold), 100
ohm resistor, (brown, black, brown, gold), BAT85 diode, BC557 transistor, battery holder for
two AAA batteries, two AAA 1.2V rechargeable batteries, wire jumpers, red led.
How it works: When the sun shines, the
voltage generated by the solar cell will be
higher than the voltage of the batteries, so a
current will flow from the solar cell to the
batteries. This current will charge the
batteries. The BAT85 diode prevents
discharging of the batteries trough the solar
cell in low light conditions. The base of the
transistor is tied to gr ound (-) by means of the
4K7 resistor. This c auses the transistor to
turn on and supply power to the µcontroller.
The controller will behave identical to project
2, so the led will flash. H owever, note that the
base of the transistor is also tied to the (+) of
the solar cell, so as long as the sun shines,
the base of the transistor is kept high enough
to prevent turn-on of the transistor, so the led
remains off at daytime.