This project is built as an experiment into MPE (MIDI Polyphonic Expression). It is being prototyped as a browser-based controller before being built as a standalone hardware controller.
Scope of the project:
- Set four oscillators to sound "nice". Make a chord or something.
- Store the current state into a register by pressing the SET button.
- Set the oscillators again to a different chord.
- Store the new state into the next register by pressing SET again.
- Repeat until you have the chord progression you want.
- Use the main knob to transition between register 1 and 2.
- When the main knob reaches 100%, moving it back to 0% will transition between 2 and 3.
- This "ping pong" transition will loop around to the first register when the last one is reached.
To quickly prototype this working, a browser-based controller is made. No frills, just black and white, dirty code.
There will be only one button on the physical product, which will have three functions:
- Press once: SET
- Hold for 1 second: Reset to register 0
- Hold for 5 seconds: CLEAR
Instead of using the START/STOP/LEARN buttons, each oscillator will have its own on-off switch. This also helps when tuning an oscillator, allowing the others to be temporarily muted.
Items are purchased locally where possible. RF Potts in Derby, UK is a good supplier of hobby electronics parts.
- 1 x metal enclosure box: £5.00
- 4 x 13 mm pot knobs: £0.63 ea
- 1 x 30 mm pot knob: £1.26 ea
- 4 x On/off toggle switch: £1.25 ea
- 1 x metal push-to-make button: £2.00 ea
- 1 x surface-mountable female MIDI port: £0.40 ea
- 1 x stripboard: £1.50 ea
- 1 x ATMEGA328P microcontroller: £5.49 ea
- 1 x 7805 voltage regulator: £0.68 ea
- 2 x 22 0Ω resistor: £0.05 ea
- 1 x 10 kΩ resistor: £0.05 ea
- 2 x 10 uF capacitor: £0.32 ea
- 1 x 16 MHz clock crystal: £0.55 ea
- 2 x 22 pF capacitor: £0.28 ea
- 5 x 10 kΩ linear potentiometers: £1.60 ea
// TODO: Hardware is currently WIP