Quantity   Component name
4 × Arduino Nano For modules. Larger module use 2x
1 × Arduino UNO (standalone and midi) For receiver station.
1 × Raspberry PI (for standalone version) Used with standalone version of Musi. It's better than previously used Sparkfun MP3 shield which couldn't handle multichannel audio. RPI is not used with MIDI version.
4 × nrf24l01 For communication
12 × HC-SR04 Ultrasonic range sensors
12 × White LED
3 × LI-PO 7.4 1300mAh battery
1 × Speaker (any)