Load Counter

Ultrasonic distance counter using two US-100 sensors displayed on a 32x64 RGB LED matrix. Runs on a Raspberry Pi with an Adafruit RGB Matrix HAT.

Hardware

• Raspberry Pi (with Adafruit RGB Matrix HAT)
• 2x US-100 ultrasonic sensors (connected via USB serial: /dev/ttyUSB0, /dev/ttyUSB1)
• 32x64 RGB LED matrix panel

Setup

On the Pi

Make sure the virtualenv at ~/loadcounter/env has the dependencies installed:

pip install adafruit-circuitpython-us100 pyserial rgbmatrix

Install as a service (from your Mac)

./setup-service.sh

This installs a systemd service that starts on boot and auto-restarts on crash.

Usage

Deploy code changes

Edit the Python files locally, then push to the Pi and restart:

./deploy.sh

View logs

./logs.sh              # live tail (Ctrl+C to stop)
./logs.sh last         # last 100 lines
./logs.sh last 500     # last N lines
./logs.sh prev         # logs from previous boot
./logs.sh today        # today's logs
./logs.sh status       # service status

Counter event logs

Count events are appended as JSON Lines on the Pi:

/var/lib/loadcounter/events.jsonl

Logged event names are counter_triggered, manual_number_changed, and counter_reset.

The iPhone app's History screen reads this same file through a paginated BLE characteristic. It does not create or maintain a second event log on the Pi. When no Pi is connected, the same screen can generate deterministic sample data on the iPhone to test its charts, filters, statistics, and PDF reports offline.

Control from your Mac keyboard

Run the remote keyboard controller from this repo:

./loadcounter-remote.py

It opens one SSH connection to jul@raspberry.local and sends the same commands the Bluetooth keyboard listener writes on the Pi. Use the arrow keys, Return, Escape, Space, digits, ., Backspace, r, y, and n. Press q or Ctrl+C to quit the Mac controller.

For one-shot commands:

./loadcounter-remote.py --send esc no enter

Control from iPhone over Bluetooth

Open the SwiftUI app project in Xcode:

ios/LoadCounterRemote/LoadCounterRemote.xcodeproj

Run it on the iPhone, then tap Connect. The Pi advertises as LoadCounter through the loadcounter-ble.service systemd service.

Test sensors

ssh jul@192.168.1.218
cd ~/loadcounter
./env/bin/python test-ultrasonic.sensors.py

Run unit tests

python3 -m unittest discover -s tests -v

Files

File	Description
load-counter.py	Main script — reads sensors, displays on matrix
loadcounter-remote.py	Mac-side CLI keyboard controller over SSH
loadcounter-ble.py	Pi-side Bluetooth Low Energy command bridge
test-ultrasonic.sensors.py	Sensor test script (distance + temperature)
fonts/	BDF bitmap fonts for the matrix display
loadcounter.service	systemd unit file
setup-service.sh	One-time service installation (run from Mac)
deploy.sh	Push code to Pi and restart (run from Mac)
logs.sh	View service logs (run from Mac)