Introduction: Sonoff Basic Rebuild to Low Voltage (12V)

About: Hello! I'm Felix ;)

Hello guys. Wouldn' t it be nice sometimes to control all your appliences and all your stuff with a WiFi smart switch? But often you don' t need to switch 230V AC. If you create a Short Circuit during wiring theres a risk of an electric shock - This can be very dangerous! I looked for a way to switch on/off my LED Strips using a Sonoff without switching 230V of the power supply. So in this Instructable I'm going to show you how to create your very own WiFi Smart Switch for voltages up to 35V DC using only a few components:

-1x SONOFF BASIC 100-230V 10A:

-1x Small PCB (I cutted a piece of a 2x8cm PCB)

-1x L7805 Voltage Regulator

-2x 103 (10nF) capacitor

-cables (I used 0.14mm²)

-Some solder


-Soldering Iron

-Rotary Tool, but a cutter would also do the job as fine :)

So let' s begin!

If you don' t understand some steps, please feel free to ask and watch my YouTube Video!

Stay Creative! ;) ;D

Step 1: Disassemble the Sonoff

Take the Sonoff out of it' s cover. This step should be very easy :) You have to strip of the warranty sticker. The warranty will be lost after this Modification!

Step 2: Locate the Voltage Regulator

You have to find the Voltage regulator. This regulator steps down the +5V to +3.3V for the ESP8266. You can find the regulator (btw. a AMS1117) on the back of the PCB. It is very tiny ;)

Step 3: Soldering Part 1

Now you have to cut two lenghts of 0.14mm² cable. I used about 10 cm, because I wanted to 3d print an enclosure for the new PCB at first, but I later decided to put all the components inside the old housing. Therefore I recommend to use e.g. 5cm. This should be definitely enough. Then you have to solder the red cable (+) to the right terminal of the voltage regulator. The black Minus-wire will then be connected to the left port of the AMS1117. This step would be easier if you tin the cables at first.

Step 4: Making the New PCB

Now you have to cut a small piece out of the PCB. Make it as small as possible. I used my Rotary Tool for this. Of course you can use an oldschool cutter :). Solder the circuit as shown in the scematic and hook the Input wires up to the Input terminals of the SONOFF Basic! Look at the video if you don' t understand what I am talking about :)

Step 5: Cutting the PCB Tracks (Optional)

If you want you can cut the tracks of the PCB that are going to the old transformer (230V to low voltage). You can use for example a cutter or your Rotary Tool to do this.

Step 6: Have Fun!

After closing up the housing you can use it as before, only with the difference that your modified version only can handle up to 35V DC :) Enjoy it ;D

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