Just a small message for people who are playing with sonoff devices.
Be carefull on your use case and what you do with them. I’m not sure if it’s my fault (because I have hacked it) or if I had a faulty sonoff device but mine has burned in my son’s room while I wasn’t at home
The house is ok, but we had many toxic smoke. Fortunately no flammable things was next to it but I can’t imagine what would have happened if it had took fire in the night few meters from my baby.
I don’t want to discredit Sonoff because I use to really like their devices and there’s many chance problem is on me and my hack but I decided to remove all of them in my house and put this message here to warn other people.
My use case :
I have bought 10 sonoff to automate heating. I didn’t want to use them to do full on/off because I thought it was dangerous (not enough powerfull), so I have hacked them to play with “fil pilote” (in french) A wire that tell heater to change mode from heat to sleep.
The hack consist of cutting the pcb, and adding a 1n4007 diode (and flashing with tasmota) there are some how to on google.
This is what it look like after modification (check top left) :
I have placed a hacked sonoff behind all my heaters more than one year ago and I had no problem until this day, ha worked automagically with climate module depending on xiaomi sensors in each room and a google agenda planning to define night/away/home mode.
I had a 16A POW and it also smoked up, while the maximum it had to take was about 1800 Watts. I don’t trust them anymore.
I now use Homematic 16A for Heating devices and Blitzwolf SHP-2 16A (Tasmota flashed) for everything up to 8A with a limiter in the firmware
With Tasmota firmware you can set a limit like: 10 A for a maximum of 60 Seconds and then let it switch off.
MaxPower
Show current maximum power allowed setting
MaxPower
0 / off
Disable use maximum power monitoring
MaxPower
Set maximum allowed power
MaxPowerHold
Show current time in seconds to stay over MaxPower before power off
MaxPowerHold
1
Set default time to 10 seconds to stay over MaxPower before power off
MaxPowerHold
Set time in seconds to stay over MaxPower before power off
MaxPowerWindow
Show current time in seconds to stay power off before re-applying power up to 5 times
MaxPowerWindow
1
Set default time to 30 seconds to stay power off before re-applying power up to 5 times
MaxPowerWindow
Set time in seconds to stay power off before re-applying power up to 5 times
I really can’t see why replacing the current carrying part of a PCB with a diode is a good idea.
The 1n4007 is typically only rated at 1A, heaters are going to be in excess of 10A.
I think the best advice at this point would be to make sure you remove all of the remaining Sonoff units that you’ve modified.
As for insurance, it will vary by country and regulations regarding electric installation. However once you modify a device it’s almost certain that any insurance will be invalid.
Don’t be dumb. The fire service and/or insurance investigators are not stupid. Sonoff basic devices are not certified in any countries that I am aware of.
Since Sonoff recently made all their new basics CE compliant this makes them fully electrical code compliant and legal to use in Australia READ LOWER POST BY ME FOR MORE INFO. This means that for us if one of them starts alight and burns down the house then home insurance would have no reason to deny your claim due to an illegal electrical device. I only use the basics for switching lights and have 3 in my walls all 3 of which are the CE certified ones. Very scary to see what damage the Sonoff dis to your wall and lucky it didn’t have anything flammable around it. Ive so far never had a Sonoff smoke up on me luckily thanks for bringing awareness to the issue of unsafe home automation devices.
I guess I’m trying to even understand what the hack was supposed to accomplish?
A diode is just a device that allows current to only flow one direction (a half-wave rectifier). If you put it in the middle of the power line you have just made the load run on DC power instead of AC power. And the diode is only a passive device. It has no control inputs at all.
How does making the heater a DC load help decide how to put the heater to sleep or not?
And looking at the specs for the diode it is only rated for 1A so I’m not surprised that it burned up.
