Bees and Bats
Over
breakfast with a swimming chum I learned he had several bee hives so I
asked if he'd like to monitor the temperature inside them. What
could he say, and little did he know what we were getting into.
Around that time I'd been experimenting with a Texas Instruments
temperature probe, the TMP107. It was one of those items that
popped up in a message from DigiKey. What appealed to me was it
used a serial interface and could support cable lengths up to 1000
feet. (Data Sheet p10). Further more it could be daisy chained.
The original
interface circuit was built atop a RasPi Pro Hat using
dinky wires to attach to the floating SOIC(8) device. Since then
I have learned to mount them onto an adapter with 8 DIP pins.
(SMDPB-051212) I used a 4N35 as the Tx/Rx isolator and a simple
telephone jack as the interconnect. These
were 'carefully'
installed inside a Betty Crocker sandwhich container with two holes
melted in the sides for power and 'phone'. The box was then
screwed to the inside barn wall closest to the hives and near enough to
power. The first set of hives is about 18ft away so we ran a 25ft
line with a second Betty Crocker screwed to the cluster and acting as a
serial hub. From the hub we ran individual lines to each hive
with a sensor sealed at the far end.
The software is written in 'C' and takes a sample every hour or
so. These are collected in a log file which it attempts to e-mail
at midnight. Not much chance of this in the barn but we were able
to plug in a laptop and download the files. This can be pretty
bone-chilling at -20C as you can see on the chart. My 2108 upgrade
will use a Pi Zero W from which we hope to download the data to our
'Androids' in passing. i.e. when BotSync sees the Access Point (
and the boys at Cypress have sorted out the WiFi mess)

The chart shows five temperature records, there are three hive sensors
and one sensor
inside the Betty Crocker with the Pi-B. The fifth reading is the
temperature at Ottawa Airport recorded by Environment Canada.
This was just included as a check. The -20C was
recorded on the 10th of March and note how one of the hives is at
+20C. At the same time one of the hives looked like it had already
died and another was struggling, but managed to join the third up in
the 30s by early April. I really shouldn't make any further
comments but there's likely some gems of wisdom to be gleaned from such
observations.
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