Hey everyone,

I'm looking to add electronic scoring to a bristle dartboard and my idea is to use a grid of IR LEDs and and Phototransistors. Right now, I'm just looking into putting together some hardware and then software/ interfacing will come later.

I'm a little confused on a few things regarding IR LEDs and phototransistors. First off, here are the parts I have found. By no means am I set on these, they just seemed like a cheap and simple place to start. LED and Phototransistor. My first concern is how many LED/ Phototransistor pairs would i need to get a precise enough reading on the dart's position. I'm thinking since a dart tip is pretty thin that I would need a good amount of pairss. I should also mention that the scoring area is going to be 28" x 28". I'm also worried that if the pairs are too close then light from other LEDs can bleed into a photo transistor. For example, if the path between LED 2 and Phototransitor 2 is broken, would the beams from LED 1 and 3 be enough to bleed around the obstruction, and cause phototransistor 2 to still receive light?

Thanks in advance
Mike

 

I believe that this project is dead on arrival. Assuming sansing is beam break, there is a much greater chance of hitting a sensor pair than the board & if covering whole board, it might take 25,000 pair of sensors, assuming dart point of 3 sq mm. ?? Maybe I missed something.
Or maybe this is a large XY key-pad wiyh sensors spaced 3 mm. Now to find something like a 3 mm laser beams spaced at 3 mm. Could be done? laser at a distance with bar lens & staggered line of 3 mm mirrors, each adjustable so as to hit proper sensor.
2nd edit. Dart can have blunt point, maybe even 5 mm dia or greator. If impact point is registered, no need for dart to stick?