This paddle is deisgned to read the impact force via built-in PCB strain guage. Current design files are available in this repository, while functional do not represent the final working design. Errors are being corrected.
Using the smallest traces available from JLCPCB we embeded this pattern to be used as a strain guage. It its biased towards deflection in the length of the paddle.
I am happy the general concept works, and that the paddle is responsive. There are likely a few things we will find need to be improved after the first batch are out in the wild.
I'm really happy with two things on this board, the labelling - making the workshop easier. The second being the half-holes to reduce handle width, all though it was pointed out to me that quater holes may actually be possible and will reduce the width furthers.
If we're reading the force with the strain gauge, why bother with the accelerometer? Well a) it's a backup incase those readings are better b) it was suggested that with some sensor fusion and measurments of the mass of the paddle we can get some really accurate readings on total energy transfered. I'm not the maths person, but I am all for more options!