About

👋 Hi — I’m Mikey.

I built HeatSync because I bought a Samsung heat pump and wanted to know what it was actually doing. The wired remote shows a target temp and a fault light. The official Wi-Fi adapter routes everything through Samsung’s cloud. Neither answered the questions I had:

🌡 What’s my COP this afternoon?
🔥 Is the booster heater kicking in when I’d rather it didn’t?
💷 When should I run hot water to spend the least?

🛠 Why not just use what’s out there?

I wasn’t the first to look at this gap. A few projects already cover bits of what HeatSync does:

Havenwise — the polished commercial option
A handful of private GitHub projects — bits of bus-tap work, varying scope

The people behind them deserve real credit. Samsung NASA reverse-engineering is unglamorous, careful work, and I’ve learned from every project I looked at.

But each one I tried was one of:

🔒 Closed-source
🎯 Too narrow in scope for what I wanted
🧩 Asking too much of the rest of my home setup — a stack of Home Assistant + SmartThings + Havenwise + bridging scripts, all just to do one job

I wanted something that could see my heat pump and tune it without a baroque dependency tree. And honestly? Building it has been most of the fun.

💡 What HeatSync actually is

📏 A £25 ESP32 board that taps the same RS-485 bus the wired remote uses
📱 Every decoded sensor surfaced on a phone-friendly dashboard
🏠 ~50 entities published to Home Assistant via MQTT or the custom HACS integration
🎛 Carefully writes back to control schedule, mode, targets

I open-sourced it because heat pumps are getting installed in millions of UK homes and the people living with them shouldn’t have to choose between a vendor cloud and a black box.

🎯 Three honest beliefs

The protocol is a public interface. Samsung’s NASA bus is on RS-485 — a multi-drop standard intended for accessories. The wired remote uses it. So does Samsung’s MIM-H04EN Wi-Fi adapter. So can we, as long as we’re polite about it.
Owners deserve to see the data. A heat pump is a £6–12k investment that lasts 15+ years. Compared to that, exposing every sensor on a phone-friendly dashboard is rounding error. The information should not be a paywall.
Cloud-free is a feature, not a chore. Heat pumps work best when they’re tuned to your house — your insulation, your habits, your tariff. That tuning belongs to you, on your network. Not in a vendor’s data warehouse. HeatSync calls four external APIs (weather, carbon intensity, optional Octopus, OTA manifest) and that’s it — see Privacy & data.

❌ What it’s not trying to be

Not a Samsung replacement. Runs alongside your wired remote and the heat pump’s safety circuits. Pull the plug → it all keeps working. Bus tap is read by default, write only when you explicitly enable it.
Not a SaaS. No accounts, no subscriptions, no central server. Docs site + firmware repo. That’s it.
Not yet a commercial product. Works on my install + a handful of early adopters. Compatibility table is small. Risk-averse? Wait for v1.0.
Not anti-Samsung. Samsung makes good heat pumps. The protocol is sensibly designed. The wired remote is competent. HeatSync just adds a layer that’s accountable to the homeowner instead of the manufacturer.

🚀 How I think about it long-term

🔁 Shipped early, often, in public. I’d rather get something useful in your hands today than design the perfect thing for next year. Half the features here started as “is this even possible?” and iterated from there. Breakage notes go in the changelog.
🍴 Easy to fork. Firmware is MIT, docs are open, hardware is off-the-shelf. If I stop, you can carry on.
🧭 Honest about scope. I’m one person who works in heating tech; this is a side project. Features land when I have time + motivation, not on a roadmap quarter.

If those alignments work for you — welcome. If you need vendor support SLAs, this isn’t the right fit yet.

📬 How to reach me

🐛 Bugs / new-model reports → GitHub issues. The system-check workflow on your device generates a redacted report you can paste in — way faster than 20 back-and-forth questions.
💬 General discussion → also GitHub, for now. If a community emerges I’ll set up a Discord or similar.
✉️ Quietly → my GitHub profile has an email. Use it sparingly.

Thanks for reading this far — it means HeatSync is more than just a curiosity to you. If you install it, drop me a system-check report; it helps the project even if nothing’s broken.