45kg load cell maxing out with finger pressure

[Willy Brown]

Hi, trying to build a load cell brake pedal using a Leo Bodnar BU-0836LC board and a 45kg load cell.
https://uk.rs-online.com/mobile/p/load-cells/8937398/
When it's connected up, it's too easy to reach 100% with a firm press from a finger.
I presumed a 45kg load cell would take much more effort than this!
Have I purchased the wrong type of load cell, or wired incorrectly perhaps?
No knowledge about electronics here, can anyone help please?

 

[Willy Brown]

Apologies for the delay .
The cheap eBay pot didn't work for me, so replaced the resistor, was easier than expected. Works an absolute treat and never missed a beat.
Thanks again.

 

[Enzo Fazzi]

Was about to suggest using a loadcell with a higher rating as the pedal acts as a lever and you will only have to press about half of that rating on the pedals, then saw that the thread is a year old.

 

[Willy Brown]

Thank you for the suggestion sir, I was on a budget, and had never tinkered before so was expecting to blow stuff up and find it didn't work. Would upgrade the load cell if I wasn't saving for your Sprints!

 

[Daniel R.]

Delated because senseless

 

[Basicen]

I do not think you bought the wrong type of load cell. Based on what you just said I would diagnose that the main problem is calibration. You will need to calibrate the system to suit the maximum weight you want since your device has a rated output range of 4.5kg to 45kg.

• The link below contains a guide to setting up a simple scale for basic beginners, you will find sample calibration codes and weighing codes.
• https://tacunasystems.com/knowledge-base/force-measurement-tips/how-to-build-digital-weighing-scale/
• The following could then be the problem if you have calibrated the system initially.
• You have the connection setup wrongly.
• The strain gauge inside the load cell is probably broken, hence why it goes to full output with very small input.