I'm making myself a lazer tag system and on the boards I have assembled photo-transistors that are spaced between 1 and 2.5 inches apart. I'm trying to make it so the areas hit between the sensors will be recognized.
So far, I have tried the following and got results as follows:
Tried: High-valued load resistor attached to photo-transistor (about 470K)
Result: Sensitivity was excellent but data rate is terrible. I'm aiming for 2400bps but In that test I might have been lucky to get 300bps
Tried: lower resistor (82K)
Result: Sensitivity a bit small but the data rate recognized by the sensor is acceptable.
Tried: Direct line-of-sight with test circuits from PC serial port to PC serial port, but lazer module and photo-transistor setup is the same and still got 5V. (serial port connects through MAX232)
Result: almost no problem with 2400bps, could get 9600bps if beam directly hits the top of photo-transistor itself.
I don't know if I can do anything electrically to solve my problem but when I looked at digikey, I saw they sell convex LED lens caps that fit on the light and can accept a beam from any angle which I think will help a bit, but what if the beam hits directly between the two sensors? Is there a specific product (that digikey could sell) I can use to take that beam and make it travel across the item so that (at least one of) the two sensors can sense the light?
Only thing that comes across the top of my head is coarse-sanded plexiglass but I'm not sure if that would be good enough?
Any ideas?
So far, I have tried the following and got results as follows:
Tried: High-valued load resistor attached to photo-transistor (about 470K)
Result: Sensitivity was excellent but data rate is terrible. I'm aiming for 2400bps but In that test I might have been lucky to get 300bps
Tried: lower resistor (82K)
Result: Sensitivity a bit small but the data rate recognized by the sensor is acceptable.
Tried: Direct line-of-sight with test circuits from PC serial port to PC serial port, but lazer module and photo-transistor setup is the same and still got 5V. (serial port connects through MAX232)
Result: almost no problem with 2400bps, could get 9600bps if beam directly hits the top of photo-transistor itself.
I don't know if I can do anything electrically to solve my problem but when I looked at digikey, I saw they sell convex LED lens caps that fit on the light and can accept a beam from any angle which I think will help a bit, but what if the beam hits directly between the two sensors? Is there a specific product (that digikey could sell) I can use to take that beam and make it travel across the item so that (at least one of) the two sensors can sense the light?
Only thing that comes across the top of my head is coarse-sanded plexiglass but I'm not sure if that would be good enough?
Any ideas?