Solar powered web server

ESP8266 Thing Dev board, LTC3588 energy harvesting development board, and a 1/2W solar panel. The three small square breakout boards on the breadboard are not being used in this pic, they’re just leftovers from another project!

Using a small 6-7V, 0.5W solar panel, the LTC3588-1 energy harvesting chip, and the ESP8266 Thing Dev board, I created a small solar powered web server. This is a very simple demonstration circuit to prove a concept for another project I’m doing but the idea is pretty fun. This solar panel in bright sunlight can produce 75mA at 7V, which the LTC3588-1 then bucks down to 3.3V and stores that energy on an array of capacitors. With 1F of capacitance, I was able to turn on the ESP8266 Thing Dev microcontroller and provide a wifi access point and a web page for about 15 seconds every 5 minutes. If I can get up to about 4F of capacitance I think it will be much more useful for taking some quick sensor readings (using the HIH-6130 board shown on that breadboard) and then sending it to a server, or possibly the Phant.io service.

The software side of this was easy since I could just use a webserver example program provided with the Arduino library for the ESP8266 Thing Dev. Thanks Sparkfun and the ESP8266 community!