Dear Daniel,

I would propose that you use small solar cell arrays as those used in the calculators and toys and a tiny electronic battery charge controller to harvest

light and charge the battery whenever a light exists and therefore you can enlarge the battery life.Other types of energy harvester are of lower energy density and can not work as the light harvester.

In order to feed your circuit with harvested power wirelessly i think it may be possible when your mobile is near from your circuit. Then you can build a harvesting coil and rectifier then a converter to boost the voltage to the required operating voltage.

Best wishes

Dear Daniel,

I would propose that you use small solar cell arrays as those used in the calculators and toys and a tiny electronic battery charge controller to harvest

light and charge the battery whenever a light exists and therefore you can enlarge the battery life.Other types of energy harvester are of lower energy density and can not work as the light harvester.

In order to feed your circuit with harvested power wirelessly i think it may be possible when your mobile is near from your circuit. Then you can build a harvesting coil and rectifier then a converter to boost the voltage to the required operating voltage.

Best wishes

Dear Mr Zekry,

I appreciate the suggestion, I will for sure consider a solar cell to actively charge my device, but I think I may have worded my question incorrectly. I was asking more along the area of communication with the device, I want to know what options other than bluetooth and wifi I have. Although from some research I've done, bluetooth seems to be good at conserving power (as in battery life, to put it in other words) My initial question was whether there was an even more conservative way to approach communication between my phone and this product (through a wireless medium) if you want me to clarify anything please do ask, I am not sure if I am able to word my questions in the best way as it's my first time using a site like this.

Dear Daniel,

Welcome again!

I made you as second proposal that you can energize your device from your mobile by a technique called wireless energy harvesting. The device utilized is a rectnna or rectifier antenna. For more information please follow the paper in the link: Chapter Rectenna Systems for RF Energy Harvesting and Wireless Power Transfer

Best wishes

Hi Daniel Veloso ,

did you already decide on the maximum values of voltage and current you want to switch?

Anyway, compared to usual energy harvesting circumstances, your idea to switch the main circuit on and off by the presence or absence of incident radiation has two advantages:

First, if you use a MOSFET as switch, the load at the output of your rectifier is nearly zero because the rectifier has just to deliver the gate voltage (loaded by a very high resistance in order to discharge the gate in case of no input).

Second, there is always a supply voltage present (delivered by the battery). If your rectifier is based on MOSFETs, you can drive VGS near the threshold by the supply voltage, spending only a few nA. Then a very low input voltage will be sufficient to drive a voltage multiplying rectifier.

There are Zero-Threshold MOSFET arrays available (they need a supply voltage but no external components) but I'm afraid they are too slow to be used with the frequencies radiated by a mobile phone:

http://www.aldinc.com/ald_zerothresh.php

Hi Daniel Veloso ,

supplement to my answer above: I just learned that there are mobile phones available which can act as RFID readers at 13.52 MHz (without additional hardware). If you were using such a phone, at 13.52 MHz you could indeed take advantage of the Zero-Threshold MOSFETs mentioned above. Powered by the battery, a supply current of 10 nA, for example, would result in 87.6 uAh per year! I admit that this is not exactly passively activating but I think it has its merits.