Hack Velux remote control to connect with MQTT using .NET nanoFramework

This projects explains how to hack a Velux remote control to control your windows and connecting all this to MQTT. It adds as well an AM2320 for the temperature and humidity. All based on the beautiful .NET nanoFramework!

The reason why it's using a remote control to pilot the Velux is because otherwise you need a special box that connect to your network with a set of API and then you can pilot your Velux. I just wanted to have some fun and same few hundreds euros :-)

Here are few pictures of the final solution:

The original remote control looks like this:

Some electronic

When stripping out a remote control, be careful of screens and any elements like this. The key principle of a button is to create a contact between 2 elements, like in a physical switch. It's the exact same thing.

In the cas of my remote control, the 2 elements are round, one inside, the other outside. It's important to make sure in which direction the current is going. Equivalent of a physical switch is a saturated transistor in electronic, so that's what we will use. You can see them partially for every button on the previous picture. We will add a small resistor between the ESP32 pin and the collector to reduce the current.

Some code

I won't comment into details the code. Just that you need to have .NET nanoFramework flashed on the device, the Visual Studio extension installed. See the getting started here.

MQTT

You'll need as well a MQTT broker, I'm using Mosquitto.

Home Assistant

And finally you'll need Home Assistant as well. Integrate the MQTT as a platform.

You then add for each of the Velux as sensors:

# velux
- platform: mqtt
  state_topic: "velux/percent0"
  name: "Velux Salle de bain"
  icon: mdi:window-open
  qos: 0
  unit_of_measurement: "%"

And like this as switch:

- platform: mqtt
  name: "Velux Salle de bain"
  command_topic: "velux/action0"
  state_topic: "velux/state0"
  payload_on: "ON"
  payload_off: "OFF"
  state_on: "ON"
  state_off: "OFF"
  optimistic: false
  retain: true  
  qos: 0