I managed to build a system using Wemos D1 R1 connected to my website to retrieve data to power on or off a 5V relay. Now I would like to expand the project to control all my house outlet. Assuming I have, 5 rooms each of which has 5 electricity wires to control. My question is what is the best setup to achieve my goal in terms of efficiency and cost optimization. If I clone my current setup, I would be needing Wemos Module for every room that connecting separately to my Wifi and then to my server which seems too much for me. So what would you recommend?


  • Can I use one single central Wemos and then communicate to each room through ESP2866 or 433MHZ RF modules.
  • I would be using at least 4 channel 5V relay Module. Could it be powered using 5V in Wemos or Arduino or should be powered with adapter
  • If I want to control a fridge or AC or water heater, should I need SS Relay or any relay would suffice
  • if SS Relay to be used, I have read that heat sink or fan should be included, is that a must?

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  • 1
    Those are a lot of questions in one. You could start by using 3V relay modules that do not need an external transistor. In my home, I am using a separate ESP module, connected to my Wifi for each device that needs to be controlled. What would be the advantage of using a central module with separate 433MHz channels to other modules? It only adds complexity and unnecessary dependencies. As for your other questions, you should look into the specifications of the relays / Solid State relays.
    – StarCat
    Commented Aug 31, 2020 at 13:19
  • 1
    Just get a bunch of SWA1 WiFi socket adapters. They are ESP8266 based and you can hack them with your own code.
    – Majenko
    Commented Aug 31, 2020 at 15:06
  • 1
    @Majenko, exactly. Sonoff also makes hackable ESP8285 / ESP8266 based smart switches that can be modified to run your own code.
    – StarCat
    Commented Aug 31, 2020 at 15:39
  • why would you want to unplug your fridge or water heater? Both of those would be better with relays than SSRs, unless you deal with the SSR's heat correctly. Assume 1.5 watt of heat for every amp of current. I would much rather have 1 ESP per outlet than illegally re-wiring 4 outlets to a 4 channel relay. Wifi can handle the "traffic", don't worry about that; i ran out of reserved IPs on mine, and have dozens of static IPs going as well, yet i still have about 10-20ms lag per command, which is typical and acceptable.
    – dandavis
    Commented Aug 31, 2020 at 21:51
  • I like sonoffs, but I found "WiOn 50050" smart outlets can be controlled by node-red without cracking them open using UDP packets, so if all you need is on/off control, they are a decent low-effort option.
    – dandavis
    Commented Aug 31, 2020 at 22:02

1 Answer 1


I advice you to buy some Sonoff devices, either the basic or S20. (they are pretty cheap on AliExpress/ebay etc.) They are perfect for the job. Flash them with Tasmota, which you find on github Tasmota. Then use a RaspberryPi (or similar) as a server. Run Node-RED on this server to communicate via MQTT to all your (Sonoff) devices. Use Mosquitto as the MQTT broker. I know this sounds like a lot, but thank me later when your done.

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