Temperature sensing bee hive

Question

I am a honey bee researcher and I want to build a temperature sensing system to monitor the temperature changes in the three dimensional space within the hive body using 5 sensors on each hive frame (25 sensors on the frames), five sensors on each side (20 sensors on the sides), and 5 sensors on the top and bottom of the hive (10 sensors top + bottom). There are 55 sensors in total.
I need to collect the temperature at each sensor as well as the average temperature inside the entire hive. During winter, when the hive can be as cold as -23.3 C, the cluster temperature (~100 bees and the queen) keeps the temperature within the cluster at ~26.7 C. If the cluster breaks, the bees will freeze to death. I want to track their movement through the hive (the cluster is in constant motion).

Several engineering students have attempted to solve this problem to no avail. This project is more than 10 years old.

Essentially, I need to create a grid that will allow me to track the temperature in a 3D space. I will be connecting the sensors to a Raspberry Pi and I will connect the system to a remote transmitter / receiver.

Answer 1

I have successfully used 1-Wire temperature sensors with a Raspberry Pi to monitor various points on my domestic hot water system. The Pi was running the OpenHAB home automation system which has protocols figured out for all sorts of devices.

Figure 1. The 1-Wire temperature sensor is small, low-cost and simple to network.

The 1-wire sensors such as the Maxim DS18B20 are accurate to 0.5°C and report their data digitally over the 1-Wire bus so no calibration is required. Each chip is uniquely addressed so once up and running you have to add them one at a time to the system to figure out which is which.

I was going to advise you to purchase a 1-Wire interface board for the Pi as it sorts out all the low-level stuff and ensured the required timing accuracy independently of the Pi GPIO which may have some timing jitter. A quick search for the interface reveals that the 1-Wire interface is built into the Pi's GPIO 4. This may be a new feature in the intervening years since I purchased mine. They seem to have all the utilities you require to sort out the addressing.

Usually networks like this should be daisy-chained from sensor to sensor. The 1-Wire is tolerant of short spurs or branches if the network length is short. This works greatly to your advantage as each frame can be wired to a 3-pin connector for ease of removal / insertion.

Bee careful.