Solar-Powered Indoor Temperature & Humidity Monitoring
with a Particle Electron
This project started in the Spring of 2017, when I finally plugged in a Particle Electron board I'd had for years. I was pleasantly surprised by how easy it was to use and quickly picked up Particle's other board, the Photon, which uses WiFi instead of Cellular.
I used a sheet of scrap aluminum as the base. I cut the outline with a bandsaw and drilled all the holes by hand, both to line up with the wooden arches and for routing cable ties. The look of the wooden arches is mildly inspired by modern radiation shields for outdoor weather sensors. Unfortunately, the wood is plywood, so it did split in a few places when the screws were installed.
By using a Power Shield for the board, also made by Particle, along with a 6V solar panel and LiPo battery, it's easy to power a Photon with the sun! The list of electronics required:
- (1) Particle Photon
- (1) Particle Power Shield
- (1) DHT11 Temperature & Humidity Sensor
- (1) 6V Solar Panel
The solar panel is held in a 3D-printed enclosure of my design (file coming soon) with cable ties. I wrapped the edges of the enclosure with Kapton tape to help protect it from the heat of the sun, and used two cheap suction cups to keep it in place.
Although I've had the board and sensor logging data for weeks, the new solar panel enclosure allowed me to move the system. The solar panel is now mounted to the top of a South-facing window, and battery charging has dramatically improved since install:
To create the chart above, and monitor all the other data I care about (data trends, current status, etc.), I'm using IFTTT to populate a Google Sheet. IFTTT has support for the Particle platform, which makes it incredibly easy to have the service search for new variable values and fill a spreadsheet from there. I'm also publishing data to ThingSpeak right from the Particle code, but prefer using Google Sheets so I can mess with the data.