It just disassambled the broodminder scale to have a look at the load cells their using (it turns out they’re using these ones)
they have an interesting single-side design (which also can be used in dual-side mode).
see here for some inspiration:
I’ll update on how accurate it is.
(edited: changed part link to manufacturer’s site)
I see, it is a full bridge load module and not a half bridge “load sensor” as build in the cheap bathroom scales.
A short internet serach show prices of around 25 - 30 EUR for each of this sensor! Hmm, a bit too expensive.
I like the form factor and thought to combine 4 pieces of this similar sensor from Sparkfun a time ago
But again: Too expensive for an approach with < 100 EUR for a hive scale.
in fact the cell reference is FX1901 from TE Connectivity. Count about 25€ per unit.
As Clemens says it has an interesting form factor. I have been testing it and it shows good accuracy. However it has an important variability with high ambient temperatures. This is from my perspective the main drawback.
In essence, the Broodminder half-scale design can never measure the weight correctly, since it is only positioned on one end of the hive. Or you would need two of them. If there is a lot of brood at the fixed (not measured) side of the hive. you will barely see a weight difference, due to the small ‘arm’ in the statical structure.
However, I like the sensors!
It depends on your kind of interest: absolute figures or relative weight tendencies. In case you are mainly interested in nectar flow or not it would be ok. I have collected some numbers some time ago Open Hive "Scale Bar" for Single Side Weighting
Hi there,
at BM_Scan.py, I just discovered a Python program by Jesse Ross-Jones and Ryan Crum of HiveTool fame that reads BroodMinder’s BLE devices and sends the measurement values to the HTTP API at https://mybroodminder.com/, which I wanted to share with you in this context – see also [1][2].
With kind regards,
Andreas.
