I'm thinking of building a target board with sensors that detect where the ball hits. A kind of target used in archery. Anyone with experience in using velostat might be able to answer my questions.
- How fast does velostat react to the physical stress? Say a ball hits my board and there's a stripe of velostat underneath, with attached leads that go to the Microbit. Will I get reliable readings of the hit, or is it possible that I just miss the top reading just because the ball touch is so short? Think of a baseball hitting a wooden board.
- I'd connect stripes of Velostat side by side and connect them to the analog inputs of my Microbit. Would it be possible to determin the position of the hit, not only with the precision of the width of the stripe, but fractions of the width, by interpolating. If both stripes A and B get readings of a hit, I could compare the values to figure out the position between A and B.
- What would be a typical reading of a stripe of Velostat, say 400 mm * 30 mm, a conductive thread would run on both sides, a multimeter would connect to the threads to measure the resistance. What would it show when not pressed and what would it show when a tennis ball or baseball would be pressed at one spot? I mean, are we talking about a change from 1 Mohm to 1 kohm or from 1 kohm to 10 ohm? I'm happy with a small clue before I plan any further. I probably need additional resistors to protect my Microbit.
I'm going to test all of this, after ordering some Velostat. Microbit has only six analog inputs, but I have a plan using 12 stripes, either in two layers, forming a 6x6 quadratic matrix, or as 12 circular rings forming the target pattern of an archery target. Well, 11 rings and the bull's eye.