TAG: hardware

808K - An eurorack version of the TR-808 kickdrum

The assembled 808K module
More than one year ago I decided to build a TR-808 kickdrum clone using Eric Archer's build documentation, and the first version I put together was done on a perfboard. It took quite a while, but thanks to a wiring pen and some patience, it was finally working.
While building this version, I also found a couple of interesting mods: a decay range extension and a "pitch" pot, which I decided to integrate into the prototype.

After some months, I started experimenting with Eagle, and created the first prototype of a PCB. Back then I didn't have a modular synthesizer (lucky times!), so I ended up using an Arduino together with an optocoupler to trigger the kickdrum via MIDI: it worked quite well, and I've been using it for a while, until I started building my first Eurorack modules.
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High-accuracy 16 bit DAC for Arduino

Analog Devices AD420 serial input 16bit DAC
A 16 bit DAC solution for your Arduino! The schematic is very simple, it's just the DAC (Analog Devices AD420), a few capacitors and an operational amplifier used as voltage follower in order to provide some buffering to the DAC output. The DAC is not very cheap (around 15-18$!) but it allows to obtain a good resolution in order to satisfy all your accuracy needs... I've built the circuit using a smd-to-dil pcb adapter, but the DAC is also available in a breadboard-friendly PDIP package.
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Yet another MIDI-to-Gakken interface!

Gakken SX-150 schematics

A couple of months ago, during Homework Festival I met a guy from Sofia who had a strange machine in his setup... he told me how cheap and funny it was, so I decided to order one on ebay. Last week I received my Gakken SX-150 and started searching around the net for hacks and mods, and I found several projects and articles describing possible ways of interfacing it with MIDI and various external sensors, but, since I was already doing some experiments with a DAC board, I decided to try it with my freshly received Gakken.

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