🍺 peltier-pint

An unnecessarily complicated and wildly inefficient way to chill a pint.

Because when you’re holding a perfectly drinkable lager at 10°C, the only reasonable next step is to boot up a full ROS2 stack, engage two relays, and fire 250 watts at it until it submits to 6°C perfection.

Above: A surprisingly effective thermodynamic crime in progress.

🧪 Why I Made This

This was my way of doing something fun and functional with ROS2, beyond turtlesim and generic tutorials. I wanted to combine hardware control, topic communication, and some real-world feedback.

This is not a production-grade beverage cooler. But it is a project that brought together sensors, control loops, and reckless thermoelectric ambition in one satisfying weekend build.

Yes, I could’ve just bought a mini fridge or used an ice bucket. But where’s the fun in that?

🧊 The Cooling Strategy

• Target Temperature: 5–7°C
• Control Method: Classic bang-bang control — if it's too warm, the system turns on the cooling hardware; if it's cold enough, it turns it off.
• Hardware:
  • 4x Peltier modules
  • 4x Cooling fans
  • 2x Relays switching a 12V / 250W PSU
  • 1x DS18B20 sensor for temperature feedback
  • 1x Raspberry Pi 4
• Software: 2 ROS2 nodes — one publishes the temperature, the other controls the cooling.

📂 Files & Media

• temperature_publisher.py – Reads from the DS18B20 sensor and publishes data to the /temperature topic.
• relay_control_subscriber.py – Subscribes to /temperature, then turns the relays on/off depending on whether the reading is within range.
• start_cooler.sh – Startup script which: enables 1-Wire support for the temperature sensor, sources the workspace and launches both nodes.

⚠️ Limitations

• ⚡ Peltier cooling is wildly inefficient — Most energy turns into heat, not cold.
• 🤖 ROS2 is overkill — A full robotic middleware stack for toggling relays is unnecessary.
• 🧯 No built-in safety features — No thermal cutoff, current limiting, or fault detection — just vibes and voltage.

📈 Potential Improvements

• ❄️ Switch to a more efficient cooling method — Just use an ice bucket.
• 🧠 Replace ROS2 with a microcontroller — An ESP32 or similar could handle the logic with less power, less latency, and fewer launch files.
• 🔒 Add safety and protection features — Implement thermal cutoffs, current sensing, and watchdog timers to prevent electrical regret.