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Discussion Starter · #1 ·
I am an electronically ignorant, only semi- computer-literate late returner to slot cars.


I'm hoping to put together a parallel-port cable, to run one of the freeware lap timing systems that are available.

This is for a minimalist 3-lane routed oval track,and I'd prefer to make the detectors entirely slot-mounted, avoiding a light bridge.

I've come across things called 'Optoswitches', or 'Photodetectors' - U-shaped devices with a LED on one side, and a detector on the other - which could easily be mounted in a slot routed under the track at right angles to the track slot.

Could anyone comment on experience with these?

... and I understand that 'Darlington' means two transistors acting as a more powerful single one, but I've no idea whether we would want single or Darlington for this purpose.

Help !


David.
 

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Here is a LINK to our transatlantic friends' website (try saying that after a few pints).

There is tons of info there ........ happy hunting


ps try saying ...... Ken Dodd's dad's dog's dead when you are sober!
 

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Hello David,

Either will work with the parallel port. It is difficult to get these photo interrupters to work because the depth of the channel is usually too deep for a guide to pass through and block the beam. You are better off using a discrete IR emmiter & phototransistor pair that can be put directly below the braid or copper. You will have much better success with that format. Nothing wrong with the dead strip or light bridge methods either. Dead strip on a straight is very reliable and the light bridge works very well too.

good luck,

Bryan

AC2Car.org
 

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Phil Kalbfell
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I have used several " phototransistor" packages, for lap scoring But have not found them as good as discrete sensors. Guide colour and car speed all effect the reliability. They were fine on slow track sections, but the guide only interiors the beam very briefly. IMO the extra circuitry required to make them reliable is not worth the effort.
Just my opinion and experience.
 

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Discussion Starter · #5 ·
Thanks for the helpful replies.

Looks as though it's a bit of a thumbs down for photointerrupters,then.

Maybe I should learn to walk before trying running - and just buy some ready made stuff to begin with!

I'll report on how I get on.

David.
 

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Rich Dumas
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There is a person named Brent Carlson that sells a turnkey system like the one you are speaking of. Google Carlson's Slot Cars for more info. There can be issues with sensors that look across the slots. Cars with shallow guides do not always count properly and guides that are not completly opaque can give you problems as well.
 
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