First time poster. I’m wondering if you can help. I am trying to make a dumb sauna controller (see pic) smart, so as to be able to turn on my sauna remotely. I am very much an amateur. So be kind.
To do this I have wired one of those sonoff relays in parallel to the push button switch that toggles in on/off. I use about 2 meters of flex heat proof (link below) behind the sauna cladding to my Sonoff switch at ground level (where it’s cooler). The switch is connected directly in a NO setup with the Sonoff and works well. However, when the sauna heats to about 70 degrees the controller will turn off on its own. (Controller is higher up where it gets hot) If I turn it on again, it will stay on but turn off again after around 10 minutes. If I disconnect the flex (at the controller) and so make it dumb again, it works as normal at high temps. If I disconnect at the sonoff switch but leave the 2 meter of cable connected at controller it turns off by itself, just as it does when connected to the sonoff. So I’ve ruled out the relay. The controller gives 3VDC when I put a voltmeter on it at the controller button but after the cable span it’s only 2VDC. Just before it turns off it drops to 1VDC. However, the relay doesn’t close.
My suspicion is my length of cable and heat are combining in some way, or perhaps the type of cable, 2 meters is probably too much. I’ve reduced cable length as much as I can. Could it be that the controller, at high temps can not provide power to that length of cable? Any help or guidance very much appreciated.
Thanks for your time.
PsmGoods 32 Feet 22 Gauge Silicone Wire Super Flexible Silicone Rubber Wire Cable 22 AWG Silicone Wire 16 Feet Red/16 Feet Black (22 Gauge) https://www.amazon.co.uk/dp/B07428WN78/ref=cm_sw_r_cp_api_mWC8Bb7QJWDEK
Sonoff Smart Remote Control Wireless Switch Universal Module 4ch DC 5V 12V 32V Wifi Switch Timer Phone APP Remote Control Support Alexa Voice Control for Smart Home https://www.amazon.co.uk/dp/B07DS44LXJ/ref=cm_sw_r_cp_api_ISC8Bb1D5KN05