PiBeat
This is the web based drum sequencer created for AutomaBeat - my Raspberry Pi powered mechanical drum machine. It works across devices (tablets, mobile phones, desktops etc), using web sockets to trigger the GPIO pins through a Python server. A preview of the sequencer can be seen at pibeat.banjowise.com.
I have open sourced the code at GitHub, and an Instructable on how to create your own drum machine is here.
![](data:image/svg+xml;charset=utf-8,<svg height="1334" width="750" xmlns="http://www.w3.org/2000/svg" version="1.1"/>)
PiBeat Drum Sequencer on an iPhone