H frame or two bar frames?

[clemens]

@freedom2000

My main concern today is that this 2 bars design is by nature prone to big temperature effects if one side is under sun and the other not (front/back position with front facing south). and I believe that no compensation would work in this case.

I would not recommand the old beelogger “double” design without any sun protection for the load cell. But the new design has parts of the aluminium profile as protection. Also different Variants with L- or T-profiles or U-profiles can be arranged to act es sun protection, see Waage-Konstruktion mit 2 Wägebalken und 130 x 30 x 22 mm Wägezellen

@freedom2000

I read also that a good target of accuracy would be around 40 to 60g, which seems far from being achievable with the two bars ?

It depends on the load cells! A good one has < 20 g per 10 °C and there are others with much more, see Comparison of Different Load Cells for a 4-Point Scale - #17 by clemens but be aware that I compared a single load cell with a setup of 4 in parallel connected load cells! This is not fair, :-) and in case you spread an error of 100 g to 4 cells you got 25 g for each, so not worse at all.

@poesel

You can see the bees leaving and returning. You can see the weight increasing during the day and loosing it in the night (due to the drying of the honey).
Maybe someone can point to an existing graph of his?

This is a hive with 4 load cells in parallel. Some pictures of the scale and hive Bienen-Kunstprojekt am Haus der Statistik / "Statista"-Projekt / ZK/U - #4 by clemens and some observations and data graphs:

• Extensiv bewirtschaftetes Volk im Jahresrückblick
• Volk eingegangen und massive Räuberei (unfortunately with an interesting but not happy end)

In case you want to walk through the data take a journey at Grafana

You can also see some “bulgs” at around 16 h at Grafana I thinkt this is a temperature artefact with direct sunlight on the load cells. Just my impression not proofed.