Baking up some Raspberry Pis

Today we worked on the data loggers for the temperature sensors. These consist of a data logger and controller called a Raspberry Pi and a multiplexer. The Raspberry Pi is like a tiny credit card sized computer that is programmed using a programming language called Python. The Pi is programmed to record the readings from the temperature sensors that are installed at different depths across the site every 30 seconds and send that signal to the main data logger in the center of the site, which then transmits the data to a live feed via the site Ethernet. The multiplexer is the device that takes several inputs (ie. multiple temperature sensors readings) and forwards then as a single output to the Pi. This helps with wire management which is especially important out in the field so you are not tangled up in a bunch of wires and not sure what they are connected to!

Figure 1: Some Raspberry Pis fresh out of the oven, being tested before going out to the field.

Figure 2: Close up of the Pi in all its glory. The red light means the Pi is getting power and the green light next to it (the ACT bulb not illuminated) blinks irregularly to show that it is transmitting data to the live feed.

Since the Pis and multiplexers are not waterproof they need a little house to live in, especially at a wet site like Lyon! Using Pelican boxes we were able to retrofit them to run the wires to the Pi box and then the Ethernet and power from the main data logger in the center of the field site.

Figure 3: Casey screwing the holes into the Pelican boxes to run the wires through.

Figure 4: The Pelican box and fiberglass sheet (right) that will be sawed to fit inside and hold the Pi and multiplexers once its screwed on.

Figure 5: The finished product, ready to be deployed!

Check back soon to see these Pis getting installed in the field!