The Petoneer Smartdot Bluetooth protocol reverse-engineered.

I've built a simple webapp to play the pre-set games - check it out here - repo.

Device name: Petcat.

Service: 0xfff0.

Characteristic: 0xfff3.

Pre-set games commands (values):

• small: 0f0405000107;
• medium: 0f0405000208;
• large: 0f0405000309.

NB there's also the possibility to send "manual" commands where you can specify the exact position of the red light, but I'm still working on reverse engineering it.

These are extracts taken from the webapp as an example and to help understand how to use the protocol.

The Smartdot I have is easy to connect, filtering by the advertised name of the device - in my case PetCat - any by the provided optional services - 0xfff0.

const device = await navigator.bluetooth.requestDevice({
                filters: [
                    { name: 'PetCat' }
                ],
                optionalServices: [0xfff0]
            });
const server = await this.device.gatt?.connect?.();

const setPresetCommand = (server, command) => {
        const service = await server.getPrimaryService(0xfff0);
        const characteristic = await service.getCharacteristic(0xfff3);
        const commandValue = command.match(/.{1,2}/g);
        const value = commandValue.map(v => parseInt(v, 16));
        characteristic.writeValue(new Uint8Array(value));
    }

I've bought a Petoneer Smartdot to automate playing with my cats using Home Assistant, in particular when I'm not home.

It didn't came with an integration, so I searched for a way to build it myself, but as my knowledge of Python is very basic and I feel way more comfortable with Javascript/Typescript I've built an add-on. That was quite doing the job, but I built it somehow in a wrong way and it was continuously connecting to the Smartdot, thus blocking the Home Assistant bluetooth entirely.

After some months the new Home Assistant Bluetooth integration came out, so I thought I could finally build the integration by myself, but lacking time and knowledge of Python, I did not work on it yet.

Therefore, as suggested by @blackadder (thank you!), I am documenting here the results of my reverse engineering of the protocol, although it's not yet clear to me how the "manual" mode works.