“I was scrolling through AliExpress and found a number toy piano kits that used a 555 IC and a series of resistors. It was a stay-at-home-because-of-COVID weekend, and, having all the parts at home, I decided to try to build one from scratch, rather than wait 4 months for a kit to arrive.
I should have built it on a breadboard first, but I thought someone somewhere must have built and tested this thing, so I went ahead and just prototyped the thing. I was wrong; I don’t think it was tested at all. It made sounds, but all of the resistors were 2K (see yellow circuit diagram above, but do NOT use the yellow diagram above) and that meant that the pitch of each note was quite random.
Here is what you will need to build a toy organ that actually sounds like a toy organ:
- speaker 8 Ohm 0.5 W (or 0.25W)
- momentary tactile buttons ×8
- ON-OFF switch
- 0.1uF ceramic capacitors (104) ×3
- 4.7uF electrolytic capacitor
- Lots of resistors 1K5; 1K2; 180; 330; 270; 1K2; 1K; 680; 22; 380; 5K6; 820; 1K
- 9V battery clip
- 9V battery
- 5cm × 7cm double-sided PCB
- 8-Pin DIP socket (optional)”