A DIY LoFi SAMPLER!

It’s been a long time since I wanted to add a DIY sampler to my rack as the simplest way to get chords synth stabs to my music.
After a bit of looking around I found this cool video about using an ISD-1820 as a cheap LoFi sampler:

https://www.youtube.com/watch?v=JJU73BE90DU

So I ordered a couple of these ISD1820 boards and followed the tutorial.
Everything worked as expected, but I needed more control over that thing, like being able to control the trig and the pitch using a midi sequencer along with my DIY Midi2CV interface.

The trig: I just used a simple NPN transistor (here) configured as a switch to emulate a push button when receiving a 5V cmos pulse.

That was the easy part..now to take over the pitch aka the R4 resistor/potentiometer adjusting the sampling frequency on the ISD1820..

For that I need to convert a voltage to a resistance.
And that is a big discussion on the Internet..I put aside the solution of using JFETs and rather turned to a Digital Pot implementation.

I used a MCP41100 that I had laying around in combination with an Arduino Nano and a nice Library, as this chip needs an SPI connection.
(that is at least the easiest way for me to do it..)

I added a bit of code in the loop() to scan Analog Input A0 and convert the Midi Ctrl voltage out of the Midi2CV that I drive using Live and the Midi Controller#1:

void loop() {
valCtrl = (analogRead(analogPin)*10); // read the input pin
MyPot.setWiper( ((valCtrl-WIPER_RESISTANCE)/MAX_RESISTANCE) * 255 );
}

And that’s working!

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