You've all been helpful in the past, so here I go...
I'm building a pinewood derby racetrack that is PLC controlled. The finish time and place of finish of the racecar is determined by a phototransistor sending a signal up to a TTL input card (5 volts).
In order for a signal to register high the manual says at least 5 mA are needed, I've tried working with what I have; this involved using no resistance in the phototransistor circuit and holding a incadescent bulb pointblank to the phototransistor. The best that could be done was about 2 mA from the circuit into the input card.
I'm open to any suggestion on how I could get this to work, anything. Just try to keep it in the realm of 5 volts (24 volts and below is an option). This project is due in two weeks, we're making headway but things need to get done.
Thanks,
Andrew
I'm building a pinewood derby racetrack that is PLC controlled. The finish time and place of finish of the racecar is determined by a phototransistor sending a signal up to a TTL input card (5 volts).
In order for a signal to register high the manual says at least 5 mA are needed, I've tried working with what I have; this involved using no resistance in the phototransistor circuit and holding a incadescent bulb pointblank to the phototransistor. The best that could be done was about 2 mA from the circuit into the input card.
I'm open to any suggestion on how I could get this to work, anything. Just try to keep it in the realm of 5 volts (24 volts and below is an option). This project is due in two weeks, we're making headway but things need to get done.
Thanks,
Andrew