# Hauslane UC-PS18 external component

This ESPHome external component allows control of a Hauslane UC-PS18 range
hood by manipulating its front panel buttons and by reading the communications
from the front panel to the main control board.

## Setup

### Hardware

You will need the following hardware to wire up the range hood:

- 1x ESP device such as ESP32-C3 Super Mini
- 5x optocouplers such as 4N35\*
- 5x resistors 1 $k\Omega$
- 1x PNP transistor such as 2N3906
- 1x 2cm $\times$ 8cm perforated prototype board

\*I used 4N35 optocouplers in my build because that is what I had on hand, but
they are overkill for this application since they are only used to "press" the
front panel buttons, which uses very slow switching speeds of >250 ms. If I were
patient, I would have waited for the much cheaper PC817 which should be more
than sufficient for this task. That said, I do not guarantee that it wlll work
with PC817 optocouplers. I suggest doing a test on one of the buttons using a
breadboard before making a more permanent installation.

[YouTube video](https://youtu.be/M4eqwwUxp7Q)

For safety, unplug the range hood from the AC power source before taking it
apart. Remove the drip tray and the washable baffle filters. Use a screwdriver
to remove the 8 screws from the fan cover assembly and remove the cover. You
can then remove the 2 screws from the light assembly to detach the lights.
Be careful to support the light assembly as you remove the screws as each bulb
is attached to a cable. Detach the cables to remove the light assembly and put
it aside. This should expose two more screws on the bottom by the front panel.
Remove the screws and unclip the 3-wire harness connecting it to the main
conrol board, and you can gently pull the front panel assembly out. The front
panel is screwed into a plastic box with two smaller screws. Remove the
small screws to remove the front panel control board from the assembly.

![Wiring of the front panel control board](wiring.png)

On the front of the panel find where the 3-wire harness connects to the board.
Flip the board to the back and identify the solder points on the back. From 
left to right, these are GND, TX, and 5V. To power the ESP32-C3 (or the
variant of ESP board you are using) from the panel, connect GND on the
panel to GND on the ESP32-C3 and 5V on the panel to 5V on the ESP32-C3. To read
the state of the fans and lights, connect the transistor's emitter (on the 
2N3906 this is the leftmost leg with the flat side facing you) to RX on GPIO 6
of the ESP32-C3. The transistor's base (middle leg) connects to the TX point on
the front panel board, and the collector (rightmost leg) attaches to GND either
at the front panel board or on the ESP32-C3.

Each buttton is a capacitive spring with a single connection point to the
front panel control board at the spring's base. Shorting this point to ground
discharges the spring and acts as a press -- or more accurately a touch -- of
the button. In theory, a transistor can do the job here too, but the leakage
from the transistor will influence the capacitive spring and will not register
presses reliably. Instead, wire the output side of the optocoupler by
connecting the spring to the optocoupler collector and ground to the optocoupler
emitter. On the input side, connect GPIO pin->resistor->optocoupler anode
in series and the optocoupler cathode to ground. These can be done using GPIO 
0, 1, and 3-5 on the ESP32-C3. Avoid pin 2 if using the ESP32-C3 as it is a
strapping pin and will cause issues with detecting button presses. The sample
configuration YAML assumes the timer button is on GPIO 0, up botton on GPIO 1,
down button on GPIO 3, light button on GPIO 4, and power button on GPIO 5, but 
these can be configured in YAML.

Since a lot of new connections will need to be made to ground, I recommend using
something like a perforated prototype board and make a single connection to
ground from the prototype board to the front panel control board, then connect
all other grounds needed for the circuiti to each other using the prototype 
board. A 2cm$\times$8cm board fits perfectly in the empty space below the front panel in the front panel assemple. I also made all connections to the back of
the front panel control board with wires with female Dupont connectors, then
used male headers on the prototype board so that the additional circuitry can
easily be removed.

![Perforated prototype board](proto.png)

![ESP32-C3 and prototype board inside front panel assembly](assembly.png)

Once you have everything connected, reassemble the range hood.

### Software

Use the [uc-ps18.yaml](uc-ps18.yaml) sample configuration and change any options
such as Wi-FI and API settings to match your preferences. If you are using
different pins or a different model of ESP board, make sure to change those
blocks in the YAML file. Flash the ESP32-C3 using ESPHome. The `command` API
can be used to control the device, or you can interface the device with
something like Home Assistant for a graphical user interface. Each button on
the board can be pressed by using `command X`, where `X` is one of `timer`,
`up`, `down`, `light`, or `power`.

### Licensing

The ESPHome component code is distributed under the [GNU General Public License
version 3](LICENSE).
