MQTT smart home switch

[jwworker201]

So I hope her is someone who can help me out. I am planning to get into smart home with an Openhab controller and want to start with my lights. As I am in my flat for rent I can't change up the whole wiring so my plan would be to buy some of these sonoff switches and placing them in my fuse box to switch the according lights. But as I still want my wall switches to function I want to just buy an esp8266 board and just wire up the switch and send the request via MQTT to my OpenHAB controller which then tells the Sonoff via MQTT to switch the light on:

 

So my question is if this would be an okay solution or if I am better off building everything from scratch (so that I have the esp8266 with the switch and an relais wired up behind the wall switch)?

Thanks for your help!  

[Aelita Sophie]

In my experience, most of the time building it your self is about the same price as buying a sonoff product. Or the difference is very neglectable. For the ease of use, I would say go with sonoff (~$6). If you want to use more GPIO pins etc, go with a ESP-12E (~$3). And if you want to go to the cheap DIY route. Go with an ESP-01S(~$1).

The last 2 obviously need a power source (ESP12E a 5v supply (~$1) and ESP-01S 3.3v(~$1.50 for 10)) (And you obviously need a relay switch board, get a 5v operated one. 3.3v will still work ~$2)

If you want to be able to tell if the light is switched on. (Despite the state of the relay) you'll need something in the line of a non-invasive AC current sensor such as a SCT-013-000. You'll be needing additional components for it though. Such as a 3.5mm female jack, 33 ohm resistor, 10uF capacitor and a 10K ohm resistor. Schematics are widely available online. (For example http://www.homautomation.org/2013/09/17/current-monitoring-with-non-invasive-sensor-and-arduino/ )

 

This would make your system a little bit fancier, as you can actually let the ESP check if any current flows, thus if the light is on.

[jwworker201]

On 2.11.2017 at 1:56 PM, Aelita Sophie said:

In my experience, most of the time building it your self is about the same price as buying a sonoff product. Or the difference is very neglectable. For the ease of use, I would say go with sonoff (~$6). If you want to use more GPIO pins etc, go with a ESP-12E (~$3). And if you want to go to the cheap DIY route. Go with an ESP-01S(~$1).

The last 2 obviously need a power source (ESP12E a 5v supply (~$1) and ESP-01S 3.3v(~$1.50 for 10)) (And you obviously need a relay switch board, get a 5v operated one. 3.3v will still work ~$2)

If you want to be able to tell if the light is switched on. (Despite the state of the relay) you'll need something in the line of a non-invasive AC current sensor such as a SCT-013-000. You'll be needing additional components for it though. Such as a 3.5mm female jack, 33 ohm resistor, 10uF capacitor and a 10K ohm resistor. Schematics are widely available online. (For example http://www.homautomation.org/2013/09/17/current-monitoring-with-non-invasive-sensor-and-arduino/ )

 

This would make your system a little bit fancier, as you can actually let the ESP check if any current flows, thus if the light is on.

Wow thank you for your detailed answer! Unfortunately I think I'll put this project on hold first because I won't be a lot at home till 2018 and I will probably move again because my company is moving.. But if I am ready to yustomize my rooms with smart home, I'll consider your recommendations!