BITBA555 is an open source/open hardware hybrid analog/digital monophonic synthesizer with a digital oscillator section and analog filter, amplifier, and envelope generator sections. It also features a fully 3D printable enclosure with snap-fit so that no additional hardware is necessary.
The ethos of BITBA555 is to be as close to 100% open source and DIY as possible. All code versions, hardware schematic versions, simulation files, board files, and even 3D printed enclosure designs will be shared on this page. In order to make digesting this information more accessible, a YouTube tutorial series about the design process has been created as well.
https://www.youtube.com/watch?v=HbYsLG5ng4g
https://www.youtube.com/watch?v=4lw_u7kjT1c
https://www.youtube.com/watch?v=C3nDFvrVApo
https://www.youtube.com/watch?v=efnBC_zZduA
https://www.youtube.com/watch?v=gevD3INR1kk
https://www.youtube.com/watch?v=fseVMmLj8Y8
https://www.youtube.com/watch?v=aarRZwyo6pU
- Digital oscillator section with sine, triangle, square, and sawtooth wave output
- Dynamic programming techniques utilized to allow for underpowered ATmega328p to oscillate efficiently
- MIDI input and output with input support for MIDI note on and off messages
- Velocity sensitivity on wave amplitude for MIDI note on messages
- 4-pole analog OTA-based low-pass filter with cutoff and resonance control
- Filter self oscillates at max resonance
- Analog OTA-based amplifier section with gain control
- Analog ADSR envelope generator
- Fully 3D printed enclosure
To hear BITBA555 in a song: https://soundcloud.com/theroomdisconnect/bitbac1d/s-NRedz