Some initial enery harvesting tests

A project log for Energy harvesting from an induction hob

Wireless temperature sensor for pots and frying pans without any batteries.

Johannes CarlssonJohannes Carlsson 05/30/2015 at 19:580 Comments

A couple of weeks ago I used a grinder to make room for some insulated copper wire. Today I decided to measure how much voltage I get out from it.

Unfortunately almost no voltage at all were present. Instead I made a couple of loose coils and put on the surface and then I got some voltage. It seems like the magnetic field does not travel so long into the frying pan.

After some tests I found that 2 turns were enough to get a good voltage.

In above pictures I have measured the voltage with a 10x probe. The first picture is lowest level (U) and the next one is level 2 and the last maximum level (P). My induction hob has the following levels 0,U,1,2,3,4,5,6,7,8,9,P.

When it comes to current there seems to be plenty, short circuit them makes the warn.

The "tricky" parts here is that I need to "store" the energy for ~1.6s when using the lowest level (or perhaps it is enough to take a measurement and transmit it in 400ms) and that I need a compact circuit to convert an input voltage between 10-25v AC to 5v or 3.3v DC depending.