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[on:]

I'm a newbie to the Arduino world, but have some programming experience in Java.

I'd like to build an Arduino-based open-loop lap timer for a 200ft slalom course. There would be an infrared sensor at each end of the course whose path would be broken as a car enters and exits the course, signaling the start and stop time of each run.

Anyone have experience or advice for using the Arduino in this way? A concern of mine: will the length of the course be an issue? Rather, will the length of wire (100ft) from each IR sensor to the Arduino cause any problems with signal attenuation?

Many thanks for your time and advice.

LL

[Reply #1 on:]

Maybe this one helps - http://www.arduino.cc/playground/Code/StopWatchClass -

Anyone have experience or advice for using the Arduino in this way? A concern of mine: will the length of the course be an issue? Rather, will the length of wire (100ft) from each IR sensor to the Arduino cause any problems with signal attenuation?

100 ft is not impossible, shielded cat5 cable should work. Have you considered an XBEE (wireless) connection as an option?

[Reply #2 on:]

Anyone have experience or advice for using the Arduino in this way? A concern of mine: will the length of the course be an issue? Rather, will the length of wire (100ft) from each IR sensor to the Arduino cause any problems with signal attenuation?

Could you clarify as to what kind of "IR sensor" you are using? A part number or link to the actual device would be best.

[Reply #3 on:]

Rob - nope, I'd never even heard of XBEE until now - I could use two of them on one Arduino?

Chagrin - I have 2 AiM IR Beacon Transmitters, model TL0600 - http://www.magnaracing.com/index.php?main_page=product_info&products_id=2001

and 2 receiver breakouts - http://www.sparkfun.com/products/8554

Thanks for your help!

[Reply #4 on:]

Rob - nope, I'd never even heard of XBEE until now - I could use two of them on one Arduino?

Chagrin - I have 2 AiM IR Beacon Transmitters, model TL0600 - http://www.magnaracing.com/index.php?main_page=product_info&products_id=2001

and 2 receiver breakouts - http://www.sparkfun.com/products/8554

Thanks for your help!

I have built lap timers that are internal to the vehicle using Arduino and the AIM beacons you reference. But it seems you want the timer to be outside of the vehicle, stationary. Is that correct? If that is the case, you don’t need the AIM beacons.  Please clarifiy.

[Reply #5 on:]

But it seems you want the timer to be outside of the vehicle, stationary. Is that correct?

Jim- yes, I had imagined that the AiM beacons and receivers would form start and finish lines, and that the whole system would be outside the car and stationary so that multiple cars could use the course.

[Reply #6 on:]

100 - 200 ft is a big distance for IR, I'd suggest to search a project: laser "trip-wire"