If those big companies cant get it more accurate than to detect best case 8lb's, what can be achived by _anyone_ with a few dollars worth of pics?
Its all down to resolution of the revolutions(!), the difference is too small to measure amongst the big difference of wheel rotation.
Plus you will need to re-calibrate everytime you wore the tyre more on one side of the vehicle than the other, and for the way some of us drive that could be more than once a day!
you need to measure about 1/100 of a mm of wheel size, once you brake too hard and the tyre slides, more than 1/100 of a mm is gone in smoke.
Its not practical, Its not accurate, it wont work, head, hitting and wall.
I'm not saying you cant do it, I'm just saying I dont think you can beat the giants on this, use your time to find something else to measure like what we are on about in this thread, find a way to measure the rpm of a rotating cog/shaft that can be fitted to all cars and is passive so none of the car needs to be modified then we have the rpm for the dash sorted etc, or wheel speed from shaft rotation etc