scarp

Scarp is a platform for building musical toys that need buttons :) It uses a Raspberry Pi Pico as a processor.

Kits can be purchased for 56 Euros and fully assembled for 86 Euros. See below for a depiction of the BOM :) If you are more comfortable with online stores, it’s available at https://tonetoys.etsy.com and at https://www.tindie.com/stores/poetaster/

I was frustrated with my pocket operators and got some inspiration from picokore. Because I’d like to swap things in the design I decided to make a slightly bigger thing where you can actually get at all the pins. Also, I decided to make a design where you can swap the use of the SDA/SCL pins between a DAC and a display. I also wanted to add a way to move the grooves when chaining with Pocketoperators without the hassle. With scarp, it’s a few simple movements to modify the groove while your playing live.

Open Sources includes several versions as fritzing files, and a folder of different firmware.

The scarp project, named like it’s brethren, rampart and keep (aka. moat) is an experimental, open hardware design. It takes a page from todbot (circuitpython guru guy) and infinitedigits (nyblycore and pikocore) designs to make a hybrid that’s more easily extended or adapted.

Scarp can include a 4pin I2C display. Or a 4 pin I2S DAC. All the pins on the pico are exposed and you can add headers to use them. The kit and builds include an oled.

The kit also includes a 1.3 inch disply, 8 buttons, 8 leds, 2 pots and an encoder.

Special?

It features an 18650 battery holder :) I hate swapping batteries on the PO series. The battery on scarp will get you through a semester :) Important is the flexibility for modding. It has space for modifications.

The kit contents can be seen here:

Firmware

There’s a bunch of firmware experiments to build on:

The firmware directory includes a number of types of firmware. You’ll be able to do work with the bare pico sdk, circuitpython, or arduino. firmwares

Include examples for

• Mozzi library based c++.
• Euclidean PWM Pikobeatbox. My baby and ships with scarp.
• pikocore The scarp branch here: https://github.com/poetaster/pikocore/tree/scarp allows you to play the pikocore firmware, with some tweaks to adapt to this hardware layout.
• circuitpython - There is also an elaborate circuitpython audio example based on todbots https://github.com/todbot/picostepseq but including audio output ;)

The Pikobeatbox Drum sequencer started with https://github.com/poetaster/PikoBeats, derived from https://github.com/rheslip/PikoBeats for the the Pikocore. Then it got out of control. I created scarp to make a beatbox with a euclidean sequencer that’s easy to tweak quickly.

This project was inspired by Teenage Engineering, pikocore designed by Zack Scholl, the todbot circuit python audio stuff and his layouts for a simple sequencer.

It’s a lot of fun to work on.