I just bought one of these:
TLDR: Would not recommend.
It does vaugely work, but has some crazy weight-rounding malarky happening, the weight increases up to 1kg in increments of 10g (as per spec), but thereafter mostly seems to go up in 1kg increments. I can’t see why this is, it’s either a fault or a firmware feature (I suspect feature).
Either way, it’s not very useful if your robot will be close to 13.6kg, as it will go straight from 12kg to 13kg.
There may be some secrets in the firmware, I’m still trying to figure it out.
I would recommend you avoid it, for reference “50kg digital luggage scale”, the style which is built into a handle.
Would recommend postal scales for Feathers personally. Bit expensive, but not excessively so, and they have that fidelity you’re after.
What strang said
I’ve ended up with a set of scales for each weight class I do:
Jewelry scales for ants and individual beetle components
Digital kitchen scales for beetles
Postal scales for feathers
Postal scales for feathers as mentioned by the others is the move for sure.
We use these: DIGITAL 50kg 4110lb Letter / Postal / Postage / Parcel / Weighing Scales BLACK | eBay (£24ish) for BBB events for both feather and beetle now, they’re cheap and the external screen makes weighing easier.
We do have a 500g reference weight to check the accuracy for beetles (it’s maybe about 1g out)