Sonoff to Homebase Air Conditioning Unit – 636212

I’ve had a Homebase portable air conditioning unit (Model 636212) for ages, the unit removes 9000BTU of heat and is ideal for my home office, especially with the hot weather we are experiencing at the moment (May, June July 2018).

Homebase AC

I have a number of Sonoff devices so I thought I’d add remote control to the air conditioning unit, using a Jog Switch (SKU437888).

Jog Switch

The Homebase unit is turned on and off via a simple push to make button, wiring the Sonoff relay normally open contacts in parallel across the on/off switch allows a single pulse from the relay contacts to either start or stop the air conditioning unit.

on/off

The low voltage to the Sonoff is from the internal Power Supply Board, this gives out 17v DC which is well within the operating range of the device (7v -30v AD/DC).

unboxed

The picture above shows the unboxed module fixed for testing,  total cost was £6.50 and took about 30 minutes, what makes this more impressive is that the EWeLink App allows ‘Scenes’ to be setup with other Sonoff devices.

I have set the Server Cabinet Sonoff which operates the internal fan to trigger the air conditioning at 34°C, turning OFF when the temperature falls below 31°C.

2 thoughts on “Sonoff to Homebase Air Conditioning Unit – 636212”

  1. Interesting…do you have a more info on this like maybe a wiring diagram and such or maybe a website . Id like to do this

  2. Hi Ken,

    Thanks for checking in.

    I used a multimeter to locate the low voltage DC on the control PCB at the back of the unit, once you find the 4 diodes forming a bridge rectifier, use the meter to confirm the voltage, as the Sonoff inching unit takes from 5v to 32v as long as your DC is within this range you should be good to go for power, as you take the voltage directly from the PCB, the DC is available as long as the Air Conditioner is turned on at the wall.

    If you search ebay for – Sonoff DC 5V/DC 5V-32V Self-lock/inching Mode Wireless Switch Relay Module.

    The on/off switch on the Homebase unit is simply a momentary tactile button, this makes the inching unit perfect to mimic the button being pressed, I used a meter on continuity with the Air Conditioner unplugged from the mains to find the two button connections on the underside of the top panel PCB, once located, I soldered two wires
    to these connections and routed them back to the Normally Open relay contact on the inching unit.

    I mounted to inching unit outside of the Air Conditioner in a small enclosure to make future maintenance easier.

    I hope the above is ok

    Good luck with your project.

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