As tiny sound generator we use an Integrated Circuit (IC) called “Hex Schmitt Trigger Type 74HC14” which was never intended for making sound. It consists of six identical inverters and with two of them we will build one simple oscillator by using 1 resistor, 1 capacitor, 1 diode (optional), 1 solar cell and 1 piezo speaker.
It is a very cheap, loud and simple project that can be made in about 30 minutes.
Step 1: Tools and Parts
A 1 x CMOS IC SN 74 HC 14 N DIP
B 1 x Capacitor 10 uF
C 1 x Resistor 1k or 10k Ohm
D 1 x Diode BAT 43 (optional)
E 1 x Solar Cell 4,5 V / 35mA (or use an old garden light panel)
F 1x Piezo Speaker (PIEZO-SUMMER KPI-G2313L-6260) or similar
G 1 x Wires
H 2 x old mini Speaker Cases, for Piezo Speaker and Circuit
Step 2: Integrated Circuit (IC)
Start with soldering it to Pin 1 and Pin 4 of the IC.
Make sure that the mark of the IC is on the left side!
Step 3: Capacitor
Solder the capacitor to Pin 2 and Pin 3 of the IC. Don’t care about the polarity.
Step 4: Resistor and Diode
Next on our soldering list are the resistors and the diode.
Solder the resistor to Pin 3 and Pin 4 of the IC.
Even if it is not necessary you can also solder the diode (in parallel to the resistor) to Pin 3 and Pin 4 of the IC.
This will make a nice saw tooth wave sound.
Step 5: Solar Cell and Case 1
Take the red and black wire.
Solder the black wire to the solar cell (-) and the red wire to the solar cell (+).
Drill a hole into case 1 and make sure that the there is enough space to fix the solar cell with a Double-sided sticky-tape.
Step 6: Solar Cell and IC
Solder the black wire of the solar cell (-) to Pin 7 of the IC (-)
Solder the red wire of the solar cell (+)to Pin 8 of the IC (+)
Step 7: Long Wire and IC
The 50 cm to 70 cm long wire is the speaker cable.
Take it and strip of bough ends of the isolation.
Solder (-) to Pin 7 of the IC (-)
Solder (+) to Pin 4 of the IC
Step 8: Case 2 and Piezo Speaker
Solder wire (+) to piezo speaker (+) red.
Solder wire (-) to piezo speaker (-) black.
Put the piezo speakers inside.
Test your urban cricket by holding the solar cell into light.
If you here some chirping sounds your urban cricket is alive!
Step 9: Toss It!
Now let’s toss it!
…as high as you can….
And send me a picture and the location of your urban cricket.
Don’t hesitate to contact me!
At least I can send you a ready-made Urban Cricket for free.
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Sound circuit inspired by Ralf Schreiber