Opto circuit design

[atari1977]

I need an opto switch circuit that will close a circuit when its beam is broken and keep that circuit on. I'm in the process of building a rube goldberg machine, so I want this circuit to be able to detect a marble rolling through a small tube, and then turn on a few motors in the next section before the marble arrives. I don't know much about designing circuits, so if there is one available online that can do this, that would be good. The circuit that the opto switch would be turning on would just be this hot wheels booster.

 

[ronv]

Hmmm, may take a little logic. But a question or two first:
It could just turn the booster on for a fixed period of time. (easiest)
It could turn it on and then sense it is past and turn it off.
Or, it could turn it on and leave it on.
There may be others. Do you see one you like?
It could probably run from the 2 batteries in the booster.

 

[atari1977]

Turning it on for a fixed period of time would work great.

 

[atari1977]

Hmmm, may take a little logic. But a question or two first:
It could just turn the booster on for a fixed period of time. (easiest)
It could turn it on and then sense it is past and turn it off.
Or, it could turn it on and leave it on.
There may be others. Do you see one you like?
It could probably run from the 2 batteries in the booster.

So do you know of a circuit I could use? Turning the booster on for a fixed period of time would work great, I just need a circuit.

 

[ronv]

I think this would work. Turns on for about a second when the beam is broken.
You will need to get inside the booster to get to the motor. Is that possible? If not maybe it can be done from outside.
Do you have an opto picked out??

 

[atari1977]

I think this would work. Turns on for about a second when the beam is broken.
You will need to get inside the booster to get to the motor. Is that possible? If not maybe it can be done from outside.
Do you have an opto picked out??

Do you think the time can be increased? 10-20 seconds would be better. I've got the battery compartment wired up already, so that's not a problem. As for the sensor, I was going to go down to radioshack and pick up a phototransistor and LED.

 

[ronv]

You can change the 10Ufd cap to 100Ufd to increase the time.
Make sure to get the cmos 555 so it will run on the low voltage. Same with the FET. Needs to be a logic level.
Will probably have to play with the led and photo transistor.

 

[atari1977]

Alright, thanks. I've actually got this IR phototransistor, assuming I get an ir led, do you think it will work?\

 

[ronv]

I think we can make it work.