Sonoff D1 Dimmer – an improved design?

Switch things ON, OFF and now dim it too!

I’m not a stranger to ITEAD devices. I have been playing with Sonoff long enough to notice the evolution of the hardware design. The latest device: Sonoff D1 Dimmer suggests that our favourable ESP based switches are going modular not just outside. Let’s talk more about how Sonoff D1 dimmer works and open it up to investigate the changes.

Dimming lights with Sonoff D1 Dimmer

Sonoff D1 dimmer module has more than one trick up its sleeve. The modular design means that to fully enjoy the dimming experience you will need the following items:

  1. Sonoff D1 dimmer
  2. RM 433 remote
  3. RM 433 base

The complete set will set you back around $20 which isn’t terrible, but the base and the remote are optional. It’s likely, that you will have to buy some dimming bulbs as well if your existing ones are not compatible. Sonoff D1 dimmer latches to a wall switch that comes with a neutral wire, and it’s aimed at the US due to wiring standards.

If your wall switch socket doesn’t have a neutral (like mine) you could still use the Sonoff D1 dimmer in the ceiling mount providing you have enough space to fit the shell (dimensions: 47mm x 62mm x 32.5mm).

Tech specs:

  • 110V-240V 50/60Hz
  • Incandescent bulbs up to 200W
  • LED bulbs up to 100W
  • WiFi 802.11 b/g/n 2.4GHz
  • Cert CE FCC

The aim is to replace your traditional switch with an RF433MHz remote and the docking base which would replace your light switch. The remote doubles as wall interface, so my suggestion would be to get two RM 433 remotes.

Apart from the RF interface, Sonoff D1 dimmer is an ESP8285 device and operates like other Sonoff switches via eWeLink app. You can toggle lights from your phone, dim it and set sun or time-based timers. It’s nice to see basic automation rules and settings to calibrate the dimmer with less compatible bulbs by setting minimum values. This will prevent the bulbs from staying on when the dimmer is set to the lowest value.

The eWeLink app comes with Alexa, Google Assistant integrations so if you name your dimmer, you will gain the voice controls via your favourite dimming app. Despite Sonoff D1 dimmer being a new product, it doesn’t come with the DIY mode which is offered with R3 devices.

Sonoff D1 dimmer
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Dim and swithc traditional lights with smart dimmer: Sonoff D1 dimmer

Pairing

Paring process is very simple, toggle the power 3 times to reset the device, then power it up to add it via eWeLink app: quick pairing. The lightbulb should pulse when it’s in the pairing mode. To pair the RM433 remote, click the remote button within 5 seconds of the Sonoff D1 dimmer powering up.

Yes, you will be able to “pair” other 433MHz devices, just don’t expect brilliant results. I tested a 4 button Sonoff Remote that comes with Sonoff Basic R3 RF, but I was only able to change a dimming preset with it.

Dimming Bulbs

This dimmer works best with incandescent bulbs. You can use the power-saving LEDs as long as the bulbs are marked as dimmable. Unfortunately, the effect will vary from bulb to bulb.

In my tests, I was able to dim the incandescent bulb very well, but Tesco dimmable LED was only dimming about 50% before flickering. You will have to adjust the minimum level per each light to provide the best dimming experience.

Modular outside, modular inside

Secured just with one screw, Sonoff D1 dimmer was very easy to take apart. To my surprise, the hardware consist of 2 PCBs joined together with an 8 pin (narrow pins) connector.

It’s nice to see the evolution of Sonoff devices. Sonoff Basic devices had the chip embedded into a single PCB. The R3 series introduced the connectivity module, which came in WiFi and Zigbee flavours but was still soldered to the main PCB. Sonoff D1 dimmer comes with a modular design, which means that the PCB with ESP8285 chip can be removed without using tools.

The connectivity module comes with RF433MHz (XTY9J20), ESP8285 and OTA hardware switch (?). The PCB is populated with well-described GPIO pins: GND, TX, RX, Vcc and Vcc, C2CK, C2DA GND which suggests a serial and SPI interfaces available to be used! Unlike the 8-pin connector, the GPIO provided come with standard pitch. Nice!

The 8-pin connector is also well labelled and the pins are 3x GND, 2x Vcc, Buzzer, Zero _cross, control. Hacking this thing will be very simple. I think ITEAD is paying attention to what makes their hardware very popular among makers.

Conclusion

Disclaimer
This product has been provided to me for the purpose of the review. As usual, with all my reviews I reserve the right to an honest critique of the product.

Sonoff D1 dimmer is a promising step in Sonoff evolution. Open to hacking, and yet providing the experience the home automation enthusiast would expect. While Tasmota for Sonoff D1 isn’t available at the time of the writing, you could map your own configuration. Perhaps this will be something I will attempt next. If you have any thoughts about the Sonoff D1 dimmer let me know in this Reddit thread.

Sonoff D1 dimmer
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Dim and swithc traditional lights with smart dimmer: Sonoff D1 dimmer
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