I recently purchased some UM3561A 8-pin DIP ICs to design some circuits that could output some cool sound effects. I've decided to share the first circuit that I've put together. I hope you find it interesting. The circuit is very simple, and the video goes through the functionality, as well as the circuit schematic. If you have any questions, please let me know!
This circuit will allow for you to create up to four different sound effects:
1) Police siren
2) Machine gun
3) Ambulance siren
4) Fire truck siren
All you need are the following components:
1) A UM3561A IC, which costs about $3 on ebay
2) A 240k - 300k Ohm resistor
3) A 10k Ohm resistor
4) An NPN transistor (I used a 2N2222)
5) A 0.5W - 2W mini speaker (Can be taken out of a dollar store speaker set)
6) 4x push button switches
7) A 3v power supply. Can be a wall wart, but two AA batteries in series will do just fine.
8) Some wire
9) A bread board, or a solder-able proto board.
Total Cost: Under $15
One of my youtube viewers mentioned that a pull-up resistor should be used on the selector buttons that are connected to VCC, because if you press one selector pin that is connected to ground, and another that is connected to VCC at the same time, you cause a short circuit. I took not of this when putting the circuit together, but the data sheet requires a direct connection between the selector pin and VCC/GND. This is why I did not employ this. In all likelihood, a pull-up resistor would protect the circuit from shorting, and not effect the functionality. Please feel free to try it out.
Thanks again for watching!