BOM lists a 2kg and 3kg sensor but only 3kg sensor is supported by 3D parts

olkal / CG_scale

CG scale for F3X gliders

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BOM lists a 2kg and 3kg sensor but only 3kg sensor is supported by 3D parts #6

Closed JM-DfT closed 6 years ago

JM-DfT commented 6 years ago

It is mentioned that 2 kg and 3kg sensor are supported but the 3D printed parts only support 3kg sensors (drill holes for 2kg and 3kg sensors do not match),

JM-DfT commented 6 years ago

Related to the above: current BOM suggests 20mm M5 screws, but IMHO at least 25mm screw length is needed (13mm for the loadcell, 8mm for the screw hole + 5mm for the bolt). An alternative is to screw the 2 loadcells from the bottom of the centre piece, but this requires adjustment of the screw holes in the 3D print.

JM-DfT commented 6 years ago

Addendum to last post: 20mm hex socket with circular (8.5 mm) head fits from the bottom

olkal commented 6 years ago

Hi The YZC-133 load cells are availabale in at least 1kg,2kg,3kg and 5kg versions. They should all have exactly the same dimensions, as shown here: https://github.com/olkal/CG_scale/blob/master/Documentation/YZC-133_load_cell_info.pdf . If the dimensions is different, I suspect that the seller has sendt you a different load cell model.

As for the screws listed in the BOM, they should fit, but the head diameter must be max 9mm. Countersunk M5*20 screws inserted from the bottom of the frame will go aprox. 6.5mm into the M5 threaded holes in the load cell. (the screw is not supposed to go all the way through the load cell). I will see if its possible to increase the hole diameter a bit on next update.

Olav

JM-DfT commented 6 years ago

Origin of the 2kg and 3kg load sensors provided by my supplier in the Netherlands (www.opencircuits.nl) is indeed unclear - external dimensions of the sensors were exactly the same but the mounting holes are differently spaced (10 mm vs. 15mm). Point of attention for other users when ordering load sensors.

Regarding the screws: flat head screws are fine for mounting the F3J/F5J support (from the top) but not for mounting the central support (head of the screw is too high and prevents placing the cover). I used 4 screws from the bottom for the central part and this works just fine.