Ever wanted to build your own synthesizer based on old chip-tunes from the 80's? Play simple polyphonic tunes that sounds just like these old Sega Master System and Megadrive video games sounded like?

I have, so, I ordered a few SN76489 chips from ebay and a midi host interface and gave it a shot. Well, it wasn't a walk in the park for me, but, I enjoyed every moment.

First I learned how to directly interface the SN76489 and make some noise with it. There were some confusing elements to this, but, with the help of The Oddbloke Geek Blog and a few other examples, together with the chip specification document I was able to develop a simple arduino library.

Next, I had to learn how to interface a midi keyboard with a USB mini host shield. This wasn't so hard, as there is some documentation available, and good libraries exist with clear examples.

Once I understood how to control the chip and how to interface my USB midi keyboard, the only thing left to do was to write some code that would wrap all of this together and allow me use the keyboard to control the chip.

Along the way, I learned that sounds with frequency lower than those I tried to generate for 0x2f midi notes didn't sound right, so, I decided to use that to allow sending noise to the noise generator for any midi notes between 0x28 and 0x2f and also allow play notes with an oriental arab touch to it for anything lower than midi 0x28.

Looking backwards, it was a lot of fun and very interesting to build.

I hope you find it as fun and interesting as I did and that if you build one yourself, you'd be kind enough to share some pictures of it.

If you liked this project, please vote for it down below to help win the contest it participates in.

Supplies:

1 x performance board

1 x arduino nano

1 x USB mini shield

1 x SN76489 sound chip

1 x shift register 595

1 x crystal oscillator of 4MHz

1 x 5V voltage regulator 7805

1 x heat sink for the voltage regulator

3 x 10uF capacitors

wires

1 x red LED for power

1 x 220 ohm resistor to limit the LED current flow

1 x power connector for 12v power supply

1 x on/off switch

a suitable box (I built mine from an old drawer that was resting in my storage for years)