Hello everyone,
I have the following challenge; I have a ventilation unit mounted in the roof (Eico model). This is operated with a remote sending RF-signals as the height of the unit is out of reach.
The ventilation unit is mounted above a induction top. I'd like to automate such that when the induction top is switched on (power on one or more of its induction plates), a RF signal is sent to the ventilation unit to switch it off.
The solution I had in mind was to use a non-invasive current sensor connected to a microcontroller to detect when there is current on the power cable of the induction top. However, it seems that the current sensor has to be connected to only the Live wire of the power cable, something that is not easy to do non-invasive (not involving an electrician).
I do not need to measure the current, my need is only to detect startup and shutdown, and use these binary signals (on / off) to send RF signals to the ventilation unit.
Can someone advise me how to do this without having to dismantle the power cord of the induction top?
Best regards,
Anders
Re: Method to check if induction top is switched on
You want to switch the ventilation OFF when the hob is ON? That seems the wrong way round to me...
If it is only the individual hotplates that consume power, I think you will be OK if you detect any current. Otherwise, I think you need to look for the rapidly changing current as each hotplate switches on and off. A CT is unusable, as you say, because the magnetic fields from the current-carrying wires oppose each other, and the overall field sums to zero. But you might get a usable signal - depending on how the wires twist in the cable - from a Hall-effect sensor pressed hard against one side of the cable. That is where the magnetic field from the wire closest will overcome the opposing field from the wire furthest away. The position of the sensor will be critical.
Re: Method to check if induction top is switched on
Thanks for the suggestions. You spotted a mistake in my write-up; I meant turn the ventilation on when the induction top is switched on, and possibly also switch ventilation off when induction top is switched off (maybe with a delay).
I'll investigate the Hall-effect sensor, so thanks for this suggestion.
Re: Method to check if induction top is switched on
I don't know how induction tops regulate temperature because I've never used them, but I do know that cooking tops with heating elements or halogen lamps turn OFF when a set temperature is reached.
Then when it cools down a certain amount, the heating element or lamp is turned on again, until the set temperature is reached. This keeps going until you turn the thing off completely.
Just a thing to keep in mind, because you probably don't want the ventilation unit / fume extractor to turn off everytime the set temperature is reached and the induction coil is turned off.