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shodan

Led's For Timing System

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Hi All,

 

 

I want to put in a simple timing system for my new routed track - IR phototransistors hooked up to parallel port.

 

I don't want to use a gantry/light bridge setup, so I'm going to mount the IR's in recesses next to the slot with an led on the other side of the slot- so that the beam is broken by the guide.

 

Question is, what sort of led do i need? Just a plain white? Is 1500 - 4000 mcd enough?

 

Thanks!


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If you want to do "in-slot" timing, you could use the JAYCAR ZD1901 unit, look it up on their site.

 

Beware, I found "issues' with in-slot timing - put it somewhere the car is not accelerating or going TOO fast, or you may find the guides don't cut the beam properly, due to lifting front ends, or pass through the beam between sample periods, and fail to register a lap for one or the other reason.

 

I am going to have to move my ones.

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my understanding was that "In slot" is a pain in the arse.

 

If you don't want the "flash of light' thing use "invisible" light.. or is that "visible" dark??

Edited by Eno the Wonderdog

Captain's log: We are enroute to some planet whose name I cannot pronounce to do something really complicated that I don't understand.

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I also heard they have a problem picking up the blue guides!

 

I've been running micro switches recessed into the track

 

A bit tricky to setup but once done no problems

 

The only drawback is you can only run in one direction.

 

 

Gary

Edited by gazza

Quickly read this post before it is deleted or i turn grey again

Gary

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Next week I am racing at the club where the guy set these things up for their club and most of the member's home tracks - he introduced me to them and gave me wiring details. They do not have any reliability problems, so I'll chat with Hugh and pass on any tips.

 

The concept is so tidy, no overhead gantry to get bumped, and for people like me who have to pack the track away sometimes, it helps keep a basically flat surface apart from crash barriers.

 

I am pretty confident that if my sensors were in a different place on my track, I'd cure both potential causes of the missed laps.

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If you want to do "in-slot" timing, you could use the JAYCAR ZD1901 unit, look it up on their site.

 

Beware, I found "issues' with in-slot timing - put it somewhere the car is not accelerating or going TOO fast, or you may find the guides don't cut the beam properly, due to lifting front ends, or pass through the beam between sample periods, and fail to register a lap for one or the other reason.

 

I am going to have to move my ones.

 

Thanks Mate, unfortunately I'd left work before I got this reply from you.

 

I ended up getting these:

 

5mm Infrared Phototransistor - Jaycar CAT. NO# ZD1950

5mm Infrared Transmitting LED Jaycar CAT. NO# ZD1945

 

I still wasn't sure if I needed white light or infra, but infra seemed logical B) After looking at ZD1901, it seems that's exactly what i needed.

 

Do you hook up via parallel port, or some other interface?


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my understanding was that "In slot" is a pain in the arse.

 

If you don't want the "flash of light' thing use "invisible" light.. or is that "visible" dark??

 

I hope it's not too much of a pain Dave. I'm probably going to use Laptimer2000, with a view to getting PC LapCounter down the track.


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I also heard they have a problem picking up the blue guides!

 

I've been running micro switches recessed into the track

 

A bit tricky to setup but once done no problems

 

The only drawback is you can only run in one direction.

 

 

Gary

 

 

I've also read that. Apparently you need to swap the guide for a black one, or paint some black along sides....


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I haven't noticed that problem myself with blue guides on some of my scaley cars.

I can't actually imagine why blue guides would be a problem - any object opaque to IR frequency light should work the same. The only guide I am suspicious of is the Spirit white guide, as I have had more missed laps on my Dallara than any other car, but that MIGHT just be because the high torque lifts the guide part out of the slot (sometimes clean out of it) under acceleration, as opposed to the IR breaking emission through the guide.

 

Most of these sensors were designed originally to pick up a break in paper, or audio or video tape (tape end sensors), and so they have to work with some fairly thin materials.

 

Anyways, back to the subject, you hook them up to whichever ports are required in the software you choose to use.

I use both Laptimer 2000 and Ultimate Racer 3.0 - have to use U.R. on Vista powered machines by the way, Laptimer 2000 wont run on one!

I use the parallel port, and although you CAN use the serial port with Laptimer 2000 according to Gregory Braun who wrote it, in fact it doesn't work.

 

Be sure to wire the sensors AND the power supply to the IR senders with the correct polarity, and put appropriate value resistors in the positive line of the senders, to limit current flow to 20ma or thereabouts.

 

At least with those separate units you can mount the parts hard up underneath the tape for most reliable performance.

Edited by SlotsNZ

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I have used various in slot sensors over the years and I think the main problem is the time that the sensor beam is broken by the guide.Some of the computer ports seem to need a longer reaction time. I use the 3mm DSE Darlington Photo Transistors but have them thru the track with the IR transmitters mounted under my bridge. I think the 5mm units will be too big to fit the slot!

 

Phil


Phil

 

Hobart Miniature Car Club

 

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