Hi,
I am thinking of ways to detect when an electrical device is turned on and off without actually touching or modifying the existing circuitry. More specifically, I have a hand held device powered by 2 x 9V batteries and with 2 electrodes connected through leads and plugs to sockets on the device, and that way connected to the internal circuitry. When turned on, the current ramps up linearly from 0 mA to 2 mA. The ramp-up rate is 0.1 mA/s. When shut down, the current is ramped down correspondingly.
It’s been a while since I had anything to do with electronics and the Maxwell laws, and my googling didn’t give me any more clarity in whether what I was thinking of doing is possible, so my hope is that someone here could enlighten me.
So, can I use a coil around the lead/plug and detect that the device is turned on due to the changing current? Or should the coil be placed perpendicularly to the lead and plug? I would then connect the coil to a microprocessor unit and send it by GSM from a GSM module to a server and collect the data there.
Or if this is not possible at all, are there any alternative options to induction into for how to do this without this coil solution that I’m considering?
If my idea with a coil works, are there any specific considerations I should think about with regards to technical requirements on the coil. Number of turns etc. Given that the rate of change of current is 0.1 mA/s for 20 seconds, from 0 to 2 mA.
I tried to be as clear as I could. Hope my message makes sense although I’m not very well-versed in this field yet, as you can probably tell.
Best regards,
Mikael