# Lap Counter Problem



## dnybsbl (Jan 20, 2010)

one of my photo sensors doesnt work. i have tried contacting greg braun (where i purchased it) and have not heard a response in two months. 
any suggestions?


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## Ogre (Jan 31, 2007)

Wait a bit their will be someone by to make excuses for him !


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## rbrunne1 (Sep 22, 2007)

What do you mean by "doesn't work"? Did it once work? Did you try the sensor in a different lane to determine if it's the sensor or the light source?

Many of the sensors are "photoresistors" whose resistance varies with their exposure to infrared radiation (IR). Try connecting a digital ohm meter to see if the resistance changes with exposure to IR. A pretty good explanation of how these setups work can be found here http://www.cenobyte.nl/slotracemanager/hardware/index.html

There's only a few things that can go wrong:

1. Burned out IR Source
2. Burned out Photoresistor
3. Broken Wire (power to IR Source or between computer & sensor)
4. Parallel Port/Computer Issue (It's possible to damage parallel port)

Good Luck :freak:


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## dnybsbl (Jan 20, 2010)

will check it out...
it has never worked, tried it in every lane and nothing, the other three work great and always have.


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## TK Solver (Mar 18, 2004)

I'd go nuts if I had a dead (no timing/counting) lane for two months. You're a lot more patient than me. Does Radio Shack carry them? Maybe you could take that photoresistor to the local Radio Shack and see if they have the same one in stock.


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## dnybsbl (Jan 20, 2010)

[ Does Radio Shack carry them? Maybe you could take that photoresistor to the local Radio Shack and see if they have the same one in stock.[/QUOTE]

i dont know if radio shack does or not. does anyone know if they do and part number?


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## rbrunne1 (Sep 22, 2007)

dnybsbl said:


> will check it out...
> it has never worked, tried it in every lane and nothing, the other three work great and always have.


That's a real bummer 

Radio Shack sells photoresisters and phototransistors.

http://www.radioshack.com/product/index.jsp?productId=2062590

http://www.radioshack.com/product/index.jsp?productId=2049724

The phototransistors are listed on http://www.hoslotcarracing.com/

If either of these look like what you have, you could give it a try :thumbsup:

It could be as simple as a broken wire, so make sure to check the continuity of the wire before replacing the sensor


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## SwamperGene (Dec 1, 2003)

Radio Shack sells a matched emitter/detector pair, part # 276-142, that I've _always_ had success with. They also sell a single detector, part # 276-145, that I've _never_ had any luck with.

I don't know which Greg uses, if he even uses RS units.


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## SwamperGene (Dec 1, 2003)

rbrunne1 said:


> Radio Shack sells photoresisters and phototransistors.


I used to use CDS photoresistors with LED lights all the time... I work in auto salvage and I used to grab 'em from auto-sensing rear view mirrors cuz I could get known matched sets.










The only problem is that over time they seem to drift, so I had to keep cranking the LED's brighter. I liked 'em when they worked though, very reliable for a good year or so.

The RS 5-pack is a crap shoot, you're lucky if you get 2 that match.


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## SwamperGene (Dec 1, 2003)

dnybsbl did you check it at the printer port? Easy to do, simply take a 100 ohm resistor and momentarily short each pin. The printer port uses pins 10,11,12, and 13 for the lane triggers and pin 25 for ground. Just stick one end of the resistor in the ground pin, then go down the row testing each one (obviously have the software running).










If they all count there, the PC/Port is not likely the culprit. From there test at each possible point of failure...after the jack that plugs into the port, at the end of the cable, etc, til you finally test across the sensor leads.


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## ssrodder (Aug 18, 2005)

*photo sensor problems*



dnybsbl said:


> one of my photo sensors doesnt work. i have tried contacting greg braun (where i purchased it) and have not heard a response in two months.
> any suggestions?


I had problems with mine years ago. They need light shined directly on them. Went to Radio Shack and purchased some large red leds that show about a 1/4 inch light. Adjust the beam so that it shines directly on the spot where you have the sensor mounted in the track. That cured my problem. I also found his sensors to be very sensitive to other light sources. Hope this helps you out.


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## SwamperGene (Dec 1, 2003)

ssrodder said:


> I also found his sensors to be very sensitive to other light sources.


This brings up a good point. After doing many setups, I've found that most IR sensors work best with smaller holes in the track and the sides of the sensor wrapped or better yet enclosed (ie, press fit into the bottom of the table).

For accuracy, build the emitter mounting plate _first_ then use it as a template for the track, then build a bridge that will allow you to adjust the plate-mounted emitters separately from the table-mounted bridge. 

I smell another diagram coming up.


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## NTxSlotCars (May 27, 2008)

*Another idea...*

I just use a 15w incandescent bulb over my sensors. Works like a charm.
You can get em at Home Depot. It's a long bulb for an exit sign.










I gutted an old AFX lap timer that didn't work, and put foil tape inside it with a little loose foil on top. It barely even gets warm.

Rich
www.myspace.com/northtexasslotcars :thumbsup:


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## dnybsbl (Jan 20, 2010)

15W?.....i was told to use a 40W. does it really matter? what about distance away? i was told 4"-5"....


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## 1976Cordoba (Sep 20, 2000)

Ogre said:


> Wait a bit their will be someone by to make excuses for him !


Funniest thing I heard all week.


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## NTxSlotCars (May 27, 2008)

dnybsbl said:


> 15W?.....i was told to use a 40W. does it really matter? what about distance away? i was told 4"-5"....


40w works too, and a 25w. 
A 40w bulb 4-5 inches over the track makes too much heat. My IR sensors are held in with hot glue, so, heats not a good thing for me. Distance is not really an issue within a foot, unless you are using a regular bulb. The short element of a regular bulb can go out of range of some sensors if the bulb is too close. This depends on if you have a 2 or 4 lane track, and how the IR sensors are mounted. I use a clear long bulb with a long element. I had a 25w in it, but the heat was a bit too much for the structure and the track, being that close. The 15w is perfect. I've left it on all day and haven't had a problem. It counts flawlessly with both LapTimer2010 and SlotRaceManager7.0 Hope this helps. Here's a closer look at the sensors.


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