Aether's IR Transponder Design
 

How the packets are formed
 

Hardware
 

Hi Aether,

I haven't had a good look at this yet but I will read up on everything over lunch and try to get back to you. Like you, I am an Arduino tinkerer; my current project is timing & start light displays for my local RC car club.

Two things spring to mind before I read up:

1) Have you considered the ATTiny 45/85 ICs? Think of them as tiny Arduinos, they're only 8 pins in DIP/DIL packaging. About the same size as a fingernail. It would be very easy to design a custom PCB for one of these and a IR LED. Whether they're the right IC for you depends on what code you use in your Arduino sketch as they have a limited instruction set.

2) Depending on how well your IR send/receive is working, an alternative library to consider is the IR Remote library.

When I've finished my timing board project, I'm planning on making an IR LED-based personal lap counter, so I'm very interested in helping in whatever way I can.

P.S. This switching regulator would be a good way to power your transponder from the car (2S?) battery.

Best of luck!

Joe

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Awesome work figuring all of that out. Good for you!

Great stuff. Subscribed!

Subscribed! Glad to see you at the track! Looking forward to the updates. Really cool build and now you have me wanting to make one!

Hmmm - - thinking of building something like this and thought you guys might offer some insight as your well ahead of the curve electrically/software wise.

http://rcarduino.blogspot.com/2012/0...-part-one.html

I was wondering why does the IR have to blink to a frequency for a system like this to work? If your just trying to detect one car why cant you just power up a LED from your receiver (resister inline of course as needed). I only have typically one car on a local backyard track at a time and was hoping to setup something like this for hot-laps - but want a simpler transponder.

The LED is modulated at a relatively high speed so that the detector can reject noise sources and ambient light. This permits more sensitivity and reliable operation. Your TV remote control works the same way, for the same reason.

That makes sense - its been 15 years since building a boe-bot and dont remember doing any timing on the IR emitters. Still this method of switching with an arduino trinket appears to be a smaller footprint then using 555 switches and a breadboard.

quite a few of ways to set a base frequency - probably just use a tone to a pin and call it good.

IR Receiver...
 

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It wouldn't be terribly difficult to design the receiver. Is I-Laps not making them anymore? If not, then I can understand the desire to roll your own. If they are still making them, their pricing seems pretty reasonable.

I suppose that one could save a little money by making one, but I'm not sure it's worth the time. Now if it's the fun factor of creating your own that entices you, then I understand.

P.S. What wavelength is the LED emission?

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Update: Smaller Transponders...
 

A big thanks to all who have shown interest in this project! :tire: