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Project Notes

#292 H823 Audio Effects Chip

Figuring out how to use the H823 “Happy Birthday” music chip.



The H823 chip arrived in this CD4060 Dream Music Light DIY Kit and so far I have been unable to find a source for the H823 chip alone, or indeed anything approximating a datasheet.

Which of course is not unusual for these potted music chips! Figuring them out is half the fun;-)


Usage and Schematic

This is one of the simpler chips to control. At a minimum it just requires three connections:

  • VCC: I’m using 5V, unsure yet what its upper and lower limits are.
  • GND: gound
  • OUT: signal out

The signal OUT can be used to directly drive the base of a low-side NPN control of a speaker or piezo buzzer.

There is one further connection on the chip board: after some experimentation, it appears this is a volume control. Attaching a potentiometer of around 5kΩ (through to ground) allows a full range volume control (from silent to maximum volume).


Test Board

I laid out a simple circuit on protoboard (without the volume control circuit). I’m using a salvaged speaker which provides a reasonable clear output - certainly far better than the piezo buzzer often seen used with these chips in kits.



Credits and References

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This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.