OVERVIEW

Audio Stream

PiDrums is a Raspberry-Pi-powered electronic drum system that sends MIDI notes to a Mac running Garageband

It includes:

• Real-time piezo drum pad detection
• A full FastAPI backend running on the Pi
• WebSocket live pad updates
• A custom iOS app for pad configuration (enabling, threshold, MIDI note assignment)
• RTP-MIDI networking between the Pi and Mac
• And future VL53L1X digital theremin sensors also sent to garageband

Network and Midi Setup (Pi - Mac)

A. Ensure Both Devices are on the same Wi-Fi Network

Starting MIDI on the Raspberry Pi

Enter virtual environment:

cd ~/Desktop/py

source env/bin/activate

Run the RTP-MIDI server (This launches the background RTP-MIDI daemon that allows the pi to act as a MIDI device on the network):

./run_rtpmidid.sh

Configure MIDI on the Mac

Open "Audio MIDI Setup" on macOS

Search Audio MIDI Setup

In the top menu, select Window->Show MIDI Setup

Click the Network globe icon (upper right)

Create Network MIDI session

Press + to make a new session

Name it: PiDrums (MUST BE THIS EXACT NAME TO CONNECT PI)

Ensure "Enabled" (checkbox on left) is ON

Connect the Pi

Under "Sessions and Directories" on the right, 

	click on "RaspberryPiMidi" and click connect
	
	RaspberryPiMidi should now be listed under Participants  -> PiDrums session

GarageBand Setup

Open Garageband

Create a Software Instrument Track

On the left, selected Drum Kit

Enable Input Monitoring (orange speaker button on track)

Confirm Mac volume is up

Running the Drum Code on the Pi

Inside the virtual environment on the Pi run:

python3 drum_connect.py

The Pi will now:

Read piezo disks

Stream MIDI into GarageBand

Serve live pad data to the iOS app over WebSocket

MUST RESTART GARAGEBAND EVERY TIME THE PROGRAM IS RE-RUN FROM THE PI

Using the iOS App

The iOS app lets you:

View all pads (Auto-updated live via WebSocket)

Toggle pad enabled/disabled

Change each pad's MIDI note

Adjust detection thresholds

Make sure the simulator (on Mac) or iPhone in on the same Wi-Fi network as the Pi

The app automatically connects to:

	http://10.0.0.24:8000 (http://<raspberry-pi-ip>:8000)

When Finished

Stop RTP-MIDI on Raspberry Pi

./kill_rtpmidid.sh

Shut down Pi

sudo shutdown -h now

Troubleshooting

Make sure the Pi sees the Analog-to-Digital converters

sudo i2c detect -y 1

	Should see the 2 addresses of the ADS1115s

If you don't see the RaspberryPiMidi on Mac Network Screen

Ensure Pi is on Wi-Fi (Must be able to see other devices, be on private network)

Ensure rtpmidid is running

Try restarting Audio MIDI setup on Mac

Ensure firewall is off on Mac for incoming connections

If no sound coming through in GarageBand:

Restart GarageBand

Make sure Input Monitoring (orang speaker icon) is enabled

Make sure no other app is using the MIDI session

Check that the Pi is actually sending MIDI messages (via print logs)

Individual Testing

Use pidrum_midi.py to test if piezo disks can send to GarageBand

Use read_piezo.py to see if the Pi is reading hits from piezo disks

System Block Diagram

            ┌────────────────────────────┐
            │          iOS App	         │
            │  • Pad settings (note,     │
            │    threshold, enable)      │
            │  • Receives live hits      │
            │    (flashes) via WebSocket │
            └────────────┬───────────────┘
                         │ HTTP + WS
                         │
                         ▼
    ┌─────────────────────────────────────────────┐
    │               Raspberry Pi                  │
    │─────────────────────────────────────────────│
    │   FastAPI Server                            │
    │   • /pads (GET)                             │
    │   • /pads/{id}/update (POST)                │
    │   • WebSocket broadcast                     │
    │                                             │
    │   Sensor Processing                         │
    │   • 8 Piezo ADC inputs (ADS1115 @ 0x48/49)  │
    │   • Threshold detection                     │
    │   • Generates MIDI notes                    │
    │                                             │
    │   RTP-MIDI (rtpmidid)                       │
    │   • Sends MIDI over Wi-Fi                   │
    └───────────────┬────────────────────────────┘
                    │ Network MIDI (RTP-MIDI)
                    ▼									
      ┌────────────────────────────────────┐         
      │         MacBook (macOS)            │
      │────────────────────────────────────│
      │ Theremin						   |
	  |	 • Leap Motion API                 |
	  |									   |
	  |	Audio MIDI Setup                   │
      │  • Network Session "PiDrums"       │
      │  • Participant: RaspberryPiMidi    |
      │  • Advertise as MIDI device via    |
	  |    bluetooth					   |
      │                                    |
      │ GarageBand                         │
      │  • Software Instrument Track       │
      │  • Line 1 = Drumset (Piezo pads)   │
      │  • Input Monitoring ON             │
      └────────────────────────────────────┘
	                │ Bluetooth
                    ▼									
      ┌────────────────────────────────────┐         
      │         iPhone (IOS)               │
      │────────────────────────────────────│
      │ GarageBand                         │
      │  • Software Instrument Track       │
      │  • Line 1 = Theremin               │
      │  • Input Monitoring ON             │
      └────────────────────────────────────┘