Just for fun and to practice soldering, I put together the MK104, Electronic Cricket from Vellman Inc. The catalog says it can be used for fun (read practical jokes) or to simulate a hot summer night. It automatically comes on when it gets dark. The cricket repetition (time between two crickets), effect and tone are adjustable. The kit also has adjustable light sensitivity. A schematic and assembly instructions are avaliable here.It has five resitors (only three are shown on the downloadable schematic), a photo resistor, a couple of diodes, an IC socket (for the IC, a CD4093), a transistor, four capacitors, four potentiometers, a piezo speaker and 9V battery holder - all mounted to a small (41 X 56 mm) PCB (printed circuit board). I can help be amazed that after you solder all that little stuff together that the thing actually works! Good practice and fun to boot. Whenever I turn it on and it starts chirping, my son yells, "How rude!"
To hear the electronic cricket and to hear the commentary, click below.
Gabcast! Electronic Cricket
