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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.

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    \$\begingroup\$ Desired accuracy? Budget? \$\endgroup\$ – Spehro Pefhany Aug 6 '18 at 13:05
  • \$\begingroup\$ You can definitely do this with some thermocouple wire and a few loggers. The problem is... those loggers are expensive. (and the thermocouple welder is expensive as well) \$\endgroup\$ – Jeroen3 Aug 6 '18 at 13:15
  • \$\begingroup\$ I recall seeing a project in NZ 10 yrs ago with hive sound and temp monitoring to detect the hatching of a new Queen. There must be a critical mass of bees to achieve this temp rise relative to heat loss. \$\endgroup\$ – Sunnyskyguy EE75 Aug 6 '18 at 13:27
  • \$\begingroup\$ @Daniel: Your "in total" edit appears to be incorrect. I make it 25 (for 5 x 5 frames) + 20 (for 5 x 4 sides) and 10 (5 top + 5 bottom) = 55 sensors. \$\endgroup\$ – Transistor Aug 6 '18 at 13:37
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    \$\begingroup\$ Can you talk about why/how previous attempts have failed? What exactly didn't work the way you needed it to? \$\endgroup\$ – Elliot Alderson Aug 6 '18 at 14:24
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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.

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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.

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  • \$\begingroup\$ Pun intended :) \$\endgroup\$ – Daniel Tork Aug 6 '18 at 13:33
  • \$\begingroup\$ Tx. I will check this out. \$\endgroup\$ – Martin Matisoff Aug 6 '18 at 13:34
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    \$\begingroup\$ Also, when shopping for DS18B20, be aware of counterfeits. If they're suspiciously cheap, they're probably fake and may not perform well. \$\endgroup\$ – Dampmaskin Aug 6 '18 at 14:19
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    \$\begingroup\$ (Maxim applications engineer here) you can buy DS18B20 direct from Maxim at maximintegrated.com, or from digikey / mouser / element14. We don't sell on eBay / Alibaba / Amazon. \$\endgroup\$ – MarkU Aug 6 '18 at 16:58

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