break pad

I would like to measure the force with which the bolt (dark blue) pushes on the break pad (grey) to stop the wheel (light blue). I am thinking that I could put some component between the bolt and the break pad (red part). There is about 1 cm gap between the bolt and the brake pad, when the brake is in neutral. I'm thinking I will use an arduino to read the value.

What kind of component can I use? A strain gauge on the side of the red component, or maybe a capacitor that is compressed?

  • $\begingroup$ In my opinion, nothing that starts below 2k€. $\endgroup$ Commented Dec 9, 2020 at 10:26
  • 1
    $\begingroup$ Yes, probably, you can use them but this site is not about product recommendations so good hunting. Shopping questions are off-topic. $\endgroup$
    – Andy aka
    Commented Dec 9, 2020 at 10:26
  • 3
    $\begingroup$ Possibly useful search term : load cell $\endgroup$ Commented Dec 9, 2020 at 12:50
  • $\begingroup$ Without adequate support there will be very high bending moments on the bolt and on whatever is between the bolt and the pad. Most load cells measure force in one direction. You'd probably be damaging the (very expensive) loadcell. If you were to use the load cell, you'd have to make sure that the support receives any transverse forces and only transmits the axial forces. $\endgroup$
    – NMech
    Commented Dec 11, 2020 at 14:57

1 Answer 1


Short answer: You need a load cell. There are many types available, but you will probably have to choose one of the more common ones because the special ones cost big bucks.

Longer answer: You will need to mechanically constrain this whole assembly so that the load cell experiences force only on the correct axis; that won't be trivial to do.

Alternate route: You could insert a small hydraulic cylinder between the bolt and the brake pad, fill that with oil and connect it to a pressure sensor. That's probably more difficult than just using a load cell, but it's an option to consider.

  • $\begingroup$ or pneumatic. not as responsive but cheaper, less mess. $\endgroup$
    – Pete W
    Commented Jan 15, 2021 at 0:48

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