From bbtinkerer on Hackster.io:
Introduction
Moisture is a problem for most things in storage. How do you know that your storage bin is air tight? How do you know if your desiccant is still working? You could get a hygrometer but that would require your bin to be transparent enough for you to read the device.
This project is perfect for bins that are opaque or too cloudy to read a meter from the outside. I store 3d printer filament in a Pelican case that is solid black. I needed a way to make sure the case was air tight and that the desiccant still worked. This project is also great for when you need to monitor out of sight storages.
This project uses the ESP8266 Wi-Fi module and Cayenne by myDevices. The ESP8266 is inexpensive and easy to use. Cayenne is an IOT service that provides a very nice, intuitive drag and drop dashboard to display data from the ESP8266. Cayenne also monitors your data and provides custom alerts sent via text message to your phone or email.
Monitor Features
- Start-Up Test Routine
- Battery Powered
- Monitor Humidity
- Monitor Battery Voltage
- Monitor Temperature
- Monitor Wi-Fi Signal Strength