I have tried everything including a replacement board and new load cells, I can’t get this thing to measure anything consistently. Any idea what I’m doing wrong here?
I really appreciate any help, I’m about to scrap this whole project if I can’t figure this out soon.
I have measure the resistance between all of the posts for cells (if this helps)
Hi traplife.
There’s a few things that could be causing you trouble.
For A, I’ve found it’s best to solder all the load cell wires and avoid using headers. You also want to make sure that you have the correct color wires going to the right spots on the board. Black is -, white is + and red is C. Double check this first and I think that will help a lot.
On B, When you solder flux residue gets on your board and since flux residue is slightly conductive, it can cause issues with the tiny voltages coming from the load sensors. Make sure you have all the flux cleaned off the board to avoid trouble calibrating the OpenScale.
And for C, The sensors are built such that they need to be able to deform a bit and if your mounting doesn’t allow for that you’re going to have inaccurate readings. See [this post for an example on how the sensors need to be mounted to work properly.
If you follow these steps, that should clear things up for you! :-)](OpenScale Consistency Issue - SparkFun Electronics Forum)
Thank you Chris very much for getting back to me.
I will solder everything down and cleanup any flux, I want confirm I have the right color wires, I took measurements pictured above. Can you confirm my cells are wired correctly per their color? I have read that sometimes the color of the wire does not always match it’s purpose, from the resistance reading above, does this look correct?
For bench testing the cells, I expect I should be able to lay the sensors on the table and mash my giant hand over them uniformly at least see a small change in perceived weight, correct?
I want confirm I have the right color wires, I took measurements pictured above. Can you confirm my cells are wired correctly per their color?
For bench testing the cells, I expect I should be able to lay the sensors on the table and mash my giant hand over them uniformly at least see a small change in perceived weight, correct?
You may need to mash pretty hard depending on the surface you’re pressing against, but yes, you should see a small change when mashing a sensor.
Thanks man, I appreciate your help. I was left in a hot car as a child and now have mental challenges (I’m doing my best here)
If I understand correctly, RED is my common wire, when using RED as a common wire I am getting a steady raw reading of ‘-8388608’ any idea what might be next steps? I want to confirm before I solder anything down. Thanks again!
A steady reading is good. Does it change when you apply force to 1 or more lead sensors? If so, you’re probably OK to solder.
Hi Chris, it does not change when force is applied to one or any of the cells. Any ideas?
When you apply force, are you doing it so that the center T shaped section of the sensor is allowed to flex or bend? You’d want to mount the sensor so that the thinner outer section is fixed and the T shaped section is above a hole so that it can bend slightly. The pictures below might help show what I’m talking about.
If the sensor is just placed on a flat surface, it can’t deform under load and won’t produce a meaningful reading.
