So when we started keeping bees, harvesting honey, etc, i had a need to know more about what was going on.
I was initially going to try and make a bee-counter camera, but it turns out the little computer i have isn't powerful enough for that. Too bad.
Plan B: Weigh them. Lots of people weigh beehives - heavier in general is better, and there are lots of ways to find out how heavy a hive is: tip them, put bathroom scales under them periodically, etc.
But i need more. I want to know how much it weighs all the time. I want a graph of this data. Know anywhere that sells scales made for beehives? That let you make graphs and check every minute or so? Me either.
So i built one! I made a scale for my hive which reports data whenever it is asked, which is currently about every minute.
Ingredients:
* a bathroom scale ($20 on ebay)
* a microcontroller (like an arduino, an attiny85) which i could talk to via USB.
I took the scale apart and used the strain gauges and analog bits from the scale, an opamp/instrumentation amp to amplify the tiny voltage that the scale provides, and hooked it into the ADC on the microcontroller. That all connects to a little 4 watt computer in the garage, which relays the readings to another computer which stores the data.
It's now sitting under the hive and making nice graphs. So far the hive hasn't changed much in weight in the day and a half it's been running.
A couple pictures:
The scale is the yellow thing at the very bottom. Under the white base.
a graph:
The thick purple line (at the bottom) is lbs, and the other lines are used to calculate that one. The uptick at the very beginning is charlie replacing the plastic cover and the brick that holds it down.
The readings from the scale/microcontroller vary proportional to temperature, so i added some stuff to compensate for those swings. It's mathy so i won't go into it here. It works pretty well though :)
So, that's my hack for this week.
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