Portami is a portable, battery-powered polyphonic synth built around a SAMD21 microcontroller. It's designed to be a companion to small Midi keyboards.

The software is a fork of Marcel Licence's excellent code: https://github.com/marcel-licence/samd21_mini_synth

My implementation focuses on USB Midi communication (Midi-in through the onboard USB-C port) and features a push button to cycle between wave types (sine, saw, square, pulse, triangle, and noise). An RGB led inside the button changes color according to the current wave type.

Other than the onboard speaker driven by an LM386 amplifier, Portami has a 3.5" mini-jack port to plug a pair of headphones. The audio socket has a switching mechanism, disconnecting the speaker when in use.

The whole setup is powered by a 3.7V, 1100mAh li-ion battery, recharged and protected by a TP4056 USB-C charger module. A regulator boosts voltage to 5V, providing power to the Midi keyboard.