Hi!
I'm in the making of a rather small (~5x5x6cm) indoor IoT/home automation product where the main hardware consists of an MSP430 MCU, a CC1101 sub-1ghz radio a couple of sensors and a stepper motor.
What I try to figure out, is how to properly power my device. If possible, I want it to be run without the user having to either change batteries or recharge the device through a cable. In other words, I'm looking for some sort of energy harvesting solution.
The device is sleeping in the majority of the day, but wakes up now and then to deal with the radio communication and to process incoming requests to the stepper motor. The stepper motor is by far the most power-consuming part. In total, it is run at about 10-20 seconds per day while consuming about 1.2 W.
My first thoughts was using a combination of a solar panel and a rechargeable li-ion battery. I have a surface area of about about 110 cm^2 available for solar panels. Does that sound like a realizable solution (and the right type of battery for this type of application)?
Firstly, I want to make sure that powering my device from sunlight is possible. Doing some simple watt/joule calculations where I have used the power density of some solar panel given the lighting conditions of my device, tell me that the energy harvested from the light exceeds the energy spent on powering the device. Are there any efficiency factors I have to take into account in the calculation to get a more realistic result (for instance from the power management IC's and so forth)?
I have never been working with battery management and energy harvesting, so a point in the right direction would be awesome! :-)
Best Regards,
Andreas
