Intro
Today I did the first part of the build for my “Smart” home, making stuff turn on and off over wifi. I picked an easy start by using Sonoff Model S3 plug hooked into a cheap humidifier with a physical switch.
The problem I have is that the internet here in the country here in the US is not good. We have 0.7mbs for the “bargain” price of $60/month. It is almost 2021 as of this writing. My friends have had gigabit senice 2015… Come on..
Enough of the rant about the state of the internet in the US. The result is we have to be very careful with any uploads or downloads that we have to do, so in order to cut down on bandwidth, I’m installing Tasmota on our switches, so we can run OpenHab locally on our Synology.
Here is the basic procedure I used to update the firmware on each one. The key to getting it to work is to make sure to press the button when you plug it into the USB when you are programming it!
it comes in a nice package, and now it’s time to TASMOTIZE!
Here’s the steps I used:
- Take it apart
- Solder the connectors
- Add a TTL to USB converter
- HIT THE BUTTON
- plug it in
- LET GO OF THE BUTTON
- Run Tasmotizer
- Desolder and Reassemble
- Profit!
Taking it apart
I have to hand it to Sonoff, they did a great job on this product. Apple, Tesla and GM should take note of Sonoff’s reparability.
I took a small screwdriver and carefully worked the gray end off.
Then slide the two white covers off each edge as shown. This will expose the three regular Philips head screws. Unscrew them, then grab the plug and lift up. You should be left with the pile of stuff as shown below
Solder the connectors
The connector soldering is fairly straight forward in that they are all labeled on the board. We are going to use Vcc, Tx, Rx and Gnd. The other to are outputs that are 120v (in the US), so I am ignoring them. Vcc is 3v3, and Tx and Rx get crossed so it all talks. I just pretined the patches, and the wires, and then tacked them on.
Adding the TTL to USB converter.
The TTL converter is fairly straight forward. Vcc goes to 3v3, Gnd goes to Gnd, Tx goes to Rx, and Rx goes to TX. There’s a table below for those who don’t read.
| Sonoff Model S3 | USB Converter |
| Vcc | 3v3 |
| GND | GND |
| Rx | Tx |
| TX | RX |
Burning the new image (Tasmotizer)
When you first plug the S3 into the USB, make sure you are pressing the button down. It also needs to not be plugged in the mains. If you did this, go out, get a new laptop, and come back. Pressing the button puts it into a mode where it will actually write the image.
After downloading the Tasmodizer software from https://github.com/tasmota/tasmotizer Run it. It should show up something similar to below.
The only com port I had plugged into the machine at the time was the S3, and it autopopulated. I did not backup the old firmware, and I picked release, and checked “erase before flashing” because it seemed like a good idea at the time. The S3 does not auto reset, so don’t check it.
Click the Tazmotize! button, and wait for the progress bar to finish.
Once the flash is done, unplug and replug the S3, not holding down the button this time. give it a couple of seconds, and then click on the “Send config” button
There is several ways to setup the device for your wifi. This is the easiest way I found, as I already had it connected.
Type in your SSID and the WEP2 password, and if you need it an MQTT server. I did the MQTT later.
Click Save, then give it a minute or two to get an IP address. Click on the “Get IP”, and then navigate to it. If you did it right it will show the following:
A couple of interesting related pages are listed below:
- https://www.adventurousway.com/blog/rv-smart-plugs
- Note: Some of the images here are from there, as mine turned out poorly. Thanks! Great stuff!
- https://stevessmarthomeguide.com/setting-up-the-sonoff-tasmota-mqtt-switch/
- https://github.com/arendst/Tasmota
- https://tasmota.github.io/docs/openHAB/
- https://community.openhab.org/t/control-tasmota-flashed-devices-via-mqtt/104099
- https://community.openhab.org/t/tasmota-flashed-sonoff-basic-with-dht22-via-mqtt/95643