MonoTon
Arduino based step sequencer and software-synth
Video on youtube:
Features
- 8 instruments (Kick, Hat, Snare, Shaker, Clap, Noise, Sine, Square)
- Each instrument has 4 banks a 16 steps each and can be muted
- Synthesis using 8bit wavetables
- 20000Hz sampling rate
- Master is filtered through analog high-pass filter (2pole)
Hardware
- atmega1284 @ 16MHz using Mighty1284 platform
- lots of 74HC595 shift registers (for LEDs)
- MCP23S17 port extenders (for buttons)
- CD4067 multiplexer (for analog potis)
- R2R network for D/A conversion
- Some eagle files included
Lessons learned while developing
- The analog inputs are quite noisy. De-noising uses quite much cpu.
- Don't ever solder this much wires by hand. PCB services are your friend.
- Prefer DDS over an R2R ladder.
Open bugs / flaws
- Although the output is buffered by an opamp, the sound sounds distorted when using the PC's line in. If I conntect it directly to the speakers, the sound is quite clear.