How to mount button load cell (TAS606)

Sensors Force & Weight
1

I am attempting to build a rocket motor test stand for measuring thrust performance of various motors. I have an arduino uno, qwiic shield, qwiic openLog and the nau7802 qwiic scale. I bought a 50kg button load cell but cannot figure out how to mount it. There are holes on the bottom to mount to a plate, but there is no way to mount anything on top. Just setting a plate on top, with a hole cut to center on the button, will not work as any force not directly down will cause it to dismount the button. (the raised bit at the center is 2mm tall, it cannot hold anything in place)

I found many examples of mounting a bar cell (such as https://cdn.sparkfun.com/assets/learn_t … ide-02.jpg ), but have not been able to find one with a button cell anywhere online. Does anyone have an example of how to mount a single button cell?

Thanks in advance.

2

This sounds like a cool project.

As you’ve discovered, they’re really not meant for this sort of use. A single button cell might be useful if using [an arbor press to make a precision crimp or inserting a friction fit pin to a particular specification. You’ll save yourself a lot of headaches simply using a shear beam (bar) or S-beam load cell that can be appropriately mounted. Of the two, I’d probably recommend [the S-beam since they can generally be used in tension or compression and, though taller, have a smaller footprint which might be better for your force testing.

If you’re dead set on using what you have, you could build a mount for it. Picture a massively scaled down version of [this one. Expect the friction on the guide pins to be a hassle. These are normally use in a combination of three or more for weighing the contents of tanks or hoppers.](Load Cell Mounting SM-220R - Sensor Techniques Limited)](Load Cell - 200kg, S-Type (TAS501) - SEN-14282 - SparkFun Electronics)](AP-810 1/2 Ton Manual Adjustable Head Precision Lever Press | USA made arbor press | Janesville Tool & Manufacturing, Inc. Janesville, Wisconsin 53546)

3

If you use the button load cell, you’d want to screw the bottom to a mounting plate and then have a second plate that hinges down onto the little nub sticking out the top of the load cell. (All the force needs directed to the nub!)

The plate that hinges down on top of the load cell might exert a bit of force on the load cell so you would need to calibrate for that. Try to center your thrust on the plate directly over the nub for the most accurate readings.

4

I actually have a 1ton arbor press for other projects and I had thought about possibilities to use it there.

I had some other friends suggest mounting it for horizontal burn, basically the engine is suspended on its side and pushes into the cell mounted vertically instead of down onto the cell.

Either way, seems a fairly involved project to build a support rig, so I might look around to try and find a bar cell with high enough rating.