ESP8266 Community Forum

- Sat May 02, 2020 5:53 pm #86881 I'm also using the "eriksl" option

I did it by measuring the current consumed. When it's (almost) zero, it's done.

but in my case I use it to monitor the power consumption of my local webserver.
For this I just took a simple (€10-€15) Sonoff POW R2, so I didn't have to design the "High voltage" hardware myself.

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Sun May 03, 2020 2:24 am #86886

BTW as any household appliance (besides bread toasters etc) have a microcontroller these days, I don't understand why they don't come with an ethernet connector anyway, and provide a SNMP service

That would be handy but I don't believe my tumble dryer does have an MCU. The only controls are a high/low temperature switch and a mechanical timer. I think the washing machine will do though as that is far more complex.

- Sun May 03, 2020 7:22 am #86887

hmm, usually topcovers of modern household appliances are not metall.
Most modern appliance electronics are not mains isolated, so if you allready tap the internal powersupply there is no use for an optoisolator, but take care of potential differences on signals.
Tapping the power supply and sensing the power to the heater relay may be a way forward...

I have checked and you are quite right. I'm not sure what the top of my tumble dryer is made of but it's definitely not metal, which is great because I can hide whatever I make inside the dryer itself and I shan't need a case which I currently don't have.

I have used optoisolators in the past to protect low voltage circuitry from the mains. Perhaps this is not necessary but that is why I was considering using one. If the internal electronics are not isolated, doesn't this make it more important to use an optoisolator than not? I was intending to draw power from the mains via a small potted mains to 3.3V power supply. I do know the basics of electronics but I'm no electronic engineer. Have I misunderstood something?

- Sun May 03, 2020 1:53 pm #86892 not missunderstood but different concept.
My concept was based on a more modern appliance. Since yout model does not work silicon based, there is no power supply to tap into.
So your concept with a small potted 3.3V power supply goes very well with an opto isolator.
But it does not have to be a very sophisticated one, maybe you can conjure one up from a small lightbulb and a ldr (photosensitive resistor).
As very basic concept you could power the esp from the mechanical timer and sense the presence of the esp in your network as "dryer on" signal.