# esphome

## Installation

1. https://nixos.org/download/
2. direnv

Your PC timezone is important for esphome schedules, as they will use compiler's
timezone when syncing the clock (NTP).

## Compiling

```bash
$ cp -i secrets.yaml{.sample,}
$ cp -i templates/secrets.yaml{.sample,}

# Edit both secrets.yaml files.

# Compile all devices
$ nix develop --command make compile-all

# Or compile a single device
$ nix develop --command make compile-bathroomheater
```

## Flashing

To flash all devices (automatically prioritizes OTA and skips prompts):

```bash
$ nix develop --command make flash-all
```

To list devices that have not been flashed yet (i.e. have pending changes):

```bash
$ make -n flash-all | grep -E 'esphome (run|compile)'
```

To flash a single device:

```bash
$ nix develop --command make flash-bathroomheater
```

Alternatively, you can drop into the development shell and run `esphome` directly:

```bash
$ nix develop
$ esphome run bathroomheater.yaml
```

**Note:** The Makefile automatically tracks dependencies (including `!include` files and local `external_components` directories). It will natively evaluate changes and only recompile what has actually changed since the last run.

## Running remotely

If you don't have esphome installed on a computer that you connect ESP chip to,
use https://web.esphome.io/ to upload the compiled binary.

The binary resides in
`.esphome/build/<component>/.pioenvs/<component>/firmware.factory.bin`.

## Serial console

Use `screen /dev/tty.usbserial-0001 115200` (or `/dev/ttyUSB*`) to read the
console.

## Cleaning up removed MQTT entities

This can be done via `clean-mqtt` command line:

```shell
$ esphome clean-mqtt spare-power-meter.yaml \
    --topic homeassistant/binary_sensor/<component>/<entity>/config
```

or

```shell
$ esphome clean-mqtt spare-power-meter.yaml \
    --topic homeassistant/+/<component>/#
```

When `--topic` is specified, the YAML file will only be used to extract MQTT
credentials. All other topics will remain untouched.

## Hardware: heating

### Photoresistor

Schematics:

1. A0 -> 10K Ohm -> GND
2. A0 -> Photoresistor -> 3V3

Assembly:

1. Put isolation band on the legs
2. Solder legs to dupont wire (the other end has to be male)
3. Bath it in the insulation varnish
4. Think the isolation band with a fan

Color coding for RJ45 cable:

- orange: furnace
- blue: floor

5528 photoresistor: 8-20K resistance by brightness, up to 1 MOhm.
Brightness range is 1.47 - 2.2V.
Darkness is 3.267V.