This project was designed for 2 workshops i gave at Sonar Hong Kong, as an introduction to Arduino. It uses a standard Arduino UNO to build an 8-step 3-channel sequencer, connected to a custom PCB with an Arduino-based drum chip that has 8 drum sounds (based on the dsp-D8). Below video shows the ‘play’ mode of the sequencer, with the audio output connected to a small amplifier (BuffaloAmp).
The full slideshow with a step by step guide to this project is available below, and a zip with the code is here: sonar2018
The PCB has an Atmega328P-PU programmed as a ‘Duemilanove’ with 16MHz crystal (with the same bootloader i use in all of my projects). It has an LM386 amplifier with speaker output, and also a mini jack socket. The 8 drum inputs have internal pull-ups, and the drum sound is triggered by a falling edge (see slides). This first version does not have the RC low pass filter recommended by the dsp-D8 creator; it only has the DC blocking cap on the Atmega output pin. This results in a lower speaker volume which was better for the workshops.
A next project based on this drum chip is the BuffaloLabs Drum Kit: a simple extension to the above PCB with 4 touch pads to trigger 4 chosen drum sounds.
The 4 touch pads have a vibration switch (SW180) connected to 5V, with a 10K pull-down resistor on their output. This creates a short HIGH pulse. Also each channel has an LED to show when it is triggered. Below picture shows the back of the pad.
The 4 touch pads can be configured to play any of the 8 drum sounds by changing the connections to the female header on the drum PCB.