# Scratch Built Lap Counters ????



## gonegonzo (Jan 18, 2006)

Not wanting to crash in on Roffutt's post, I want to bring to light a Tarck Timing project I seen a few years back.

I forget who posted it but they built a lap counter from a hand held calculator/ One calculator was used for each lane and they were self sufficient except for the battery power.

I forget the details but thinking back it was a great way to have a counter for low bucks.

Does anyone else remember the project and can you elaborate on it ?

Also , does anyone else have a lap counter build they'd like to share ?

GoneGonzo


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## vaBcHRog (Feb 19, 2003)

Go to Weird Jacks web site that where it was at.

Look for LCD counters. Radio Shack use to sell them. 1 per lane, I don't have any pictures but our club built several in the early 90s

Roger Corie


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## Marty (Oct 20, 1999)

I built six using calculators. I found calculators at a dollar store in colors that matched my lane colors. Be careful. Buy one and try it out. I don't know if it was the reed switches, cheap calculators, or..... but mine would add extra counts when the car was on the other side of the track!!Marty


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## gonegonzo (Jan 18, 2006)

*Counter*

Marty , was your calculators solar or battery operated and does it matter ?

How do you hook them up ?

Weird jacks site is down.

Thx 

Tom D/GoneGonzo


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## Marty (Oct 20, 1999)

Mine were battery powered. I have seen calculators used successfully as lap counters on a 1/32 track.


Make sure the calculator has the "constant" feature. The trip wires from the track (reed switch, light sensor, dead track, etc...) are hooked across the "=" button. Hit 0 + 1. Every time the car passes the trip point it will add 1. Start the cars past the trip point so that the first time they cross it the calculator will read 1.

For whatever reason my cars would start the lap counter OK but half way around the track it would start adding numbers. It might have been cheap calculators. They were only $1.00 each

I'll find out from Jack what is wrong with his web site.

Marty


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## gonegonzo (Jan 18, 2006)

Thx Marty

GoneGonzo


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## weirdjack (Apr 11, 2007)

My website is at http://www.weirdjack.com
However, I have not had the calculator lap counter diagram on it for a few years now. Just do what Marty wrote.
I've had flawless performance with calculator lap counters on 1/32 tracks with a single braid dead strip. HO tracks with reed switches have not seemed quite as reliable, but not bad either. I personally had bad luck using normal dead strips on either size track. The car's motor generates enough current when passing over the dead strip to whack out the calculator circuits.
Note: I didn't invent this. I saw an old old article somewhere where a guy had a calculator suspended over his track. He glued a wire to the "equals" key and when a car hit that wire it would push the key and add a lap count. All I did differently was to wire the track directly to the the calculator's circuit board so that my cars would not be smacking a paddle-wire every lap 
WJ


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## gonegonzo (Jan 18, 2006)

Thank you for responding Jack. Ok , to confirm, I open the calculators back and put a jumper wire on the = button and the other end to a dead strip ??? 

What is a single brais dead strip ??? 

Electronics and I are starngers but I'd like to get this to work.

Thanx again.

GoneGonzo


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## weirdjack (Apr 11, 2007)

> to confirm, I open the calculators back and put a jumper wire on the = button and the other end to a dead strip ???


Yes. Just wire into the circuit that leads to the "equals" button.





> What is a single braid dead strip ???


Something I have not been able to get to function on HO cars with standard pickup shoes. 
Essentially, it is a sandwich of brass strips on their edge (with plastic insulators) laid in place of the right conductor strip. The leads of any lap counter system go to these strips. When the car's right braid passes over them, it completes the circuit. But most HO cars don't use braided pickups and solid metal shoes tend to bounce over these strips causing multiple counter trips. 
I started using these strips for 1/32 track when I used calculator counters. Because the car's motor generated sufficient current on a standard dead-strip to lock up the low voltage calculator circuits.

Honestly though, there are several shareware lap counter programs for PC's available on the net. Old PC's and CRT monitors capable enough for this purpose are usually found for free if you ask around. 
Jack


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