Yet another Arduino based track timer...

DIY timing systems
Indy
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Re: Yet another Arduino based track timer...

Post by Indy »

jzarvey wrote:Our pack has an older Fast Lane line judge. It only determines the finishing order and does not have a computer interface. Has anyone used Indy's Arduino timer to interface an older Fast Lane judge to the computer for use with GPRM? I thought I would try this route, since we have the display and finish line electronics, we just need a way to hook it up to the computer.
Sounds like a fun project - let me know if I can be of any help.
ErikRuud
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

I love this project. My pack is small and very low on funds. We do have our own four lane wooden track, but we only have an old "Lane Brain" which doesn't have times or a computer interface.

I was looking into using a Raspberry Pi to build a timer, but it looks like the low level timers in a R-Pi are not easily accessed. This gives me a system that is inexpensive and fis within my budget and time restraints.

I have an Uno R3 and most of the discreet components on hand.

I'll post my progress updates.
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Re: Yet another Arduino based track timer...

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Indy wrote:In the next week I'll release an update to the timer (new Arduino sketch, new schematics, etc.) that utilizes these displays.
OK, the holidays and a sinus cold kind of destroyed that estimate...

I do have the update finished and I'll be updating the website later tonight. In the mean time here is a short video of the testing:


https://youtu.be/5OZQKdYxG0M

And the website: http://www.miscjunk.org/mj/pg_pdt.html
hotone
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Re: Yet another Arduino based track timer...

Post by hotone »

Thanks for your work on this Indy. I picked up an arduino starter kit a couple months ago just to learn how to make this timer. Wish we had radio shack here still as I am having troubles figuring out what leds to use.

Sent from my SGH-I747M using Tapatalk 2
Indy
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Re: Yet another Arduino based track timer...

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hotone wrote:Thanks for your work on this Indy. I picked up an arduino starter kit a couple months ago just to learn how to make this timer. Wish we had radio shack here still as I am having troubles figuring out what leds to use.
Hello - I'm glad to hear that you like the project.

The only special thing about the phototransistor and LED I picked for the project is that they happened to be in stock at my nearby Radio Shack when I was building the first version. :D Do you have any type of electronics supply store available near you? If so they would probably have a phototransistor and LED that could be made to work. It does take some experimentation - my first attempt was with a matched set from Radio Shack but I was not able to get good results with it (bad range, detection angle, etc.)

The setup used is a called a common emitter phototransistor circuit. A simplified summary - when no car is present the light hitting the phototransistor pulls the input down to ground and a LOW input is seen by the Arduino. When a car blocks the sensor the dark phototransistor does nothing, the pull-up resistor is able to pull the input to 5 volts and a HIGH input is seen by the Arduino.

I have a short Arduino sketch that helps with setup and testing of the detector circuits - it basically just watches and outputs to the serial monitor (of the the Arduino IDE) when a change of state occurs. I'll get that cleaned up and post it - it might also be helpful to some of the others trying to interface the Arduino to their existing finish detectors.

Hope that helps, let me know if you have any questions.
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

Indy wrote:
hotone wrote: - my first attempt was with a matched set from Radio Shack but I was not able to get good results with it (bad range, detection angle, etc.)
I was involved in slot car racing for many years and we used similar set ups with phototransistors as well. The general consensus was that the IR Emitter/Phototransistor pairs that Radio Shack sells did not perform well. We always bought the individually packed components and got better results.
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

I just found this today. I think another revision is in order. :D

http://www.instructables.com/id/Build-a ... lay/#intro" target="_blank
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Re: Yet another Arduino based track timer...

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ErikRuud wrote:I just found this today. I think another revision is in order. :D

http://www.instructables.com/id/Build-a ... lay/#intro" target="_blank
Hmmm. One for each lane. Do you have a stadium to mount them to? :lol:

That is rather interesting. I actually have some of these for RC airplanes. They come in a variety of different colors.
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Awana Grand Prix and Pinewood Derby racing - Where a child, an adult and a small block of wood combine for a lot of fun and memories.
ErikRuud
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

We do run in a gym, but I am taking the easy way out and using a video projector.

I got to test this out tonight on a bread board with three lanes and it worked very well! I even tested it with GPRM and it is working great. I was going to go for a four lane test, but one of the phototransistors was DOA.

Now I have to build it for real.

I'll post pictures of the breadboard tomorrow.
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

Here are the pictures from last nights testing. I was using the first version of the arduino sketch.

This is the quick bread board set up just to see if it would all work. I didn't put in the "Win" LED for lane 3.
Image

This is a shot of the screen from PDT3.
Image

This is the timer test screen in GPRM.
Image

I really want to thank you Indy for sharing your work with the rest of us. This has saved me a lot of time and saved my pack some money.

Sooner or later I will probably start tinkering with the code because I just can't help it. :thinking:
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Re: Yet another Arduino based track timer...

Post by hotone »

Indy wrote:Do you have any type of electronics supply store available near you? If so they would probably have a phototransistor and LED that could be made to work. It does take some experimentation - my first attempt was with a matched set from Radio Shack but I was not able to get good results with it (bad range, detection angle, etc.)

The setup used is a called a common emitter phototransistor circuit. A simplified summary - when no car is present the light hitting the phototransistor pulls the input down to ground and a LOW input is seen by the Arduino. When a car blocks the sensor the dark phototransistor does nothing, the pull-up resistor is able to pull the input to 5 volts and a HIGH input is seen by the Arduino.

I have a short Arduino sketch that helps with setup and testing of the detector circuits - it basically just watches and outputs to the serial monitor (of the the Arduino IDE) when a change of state occurs. I'll get that cleaned up and post it - it might also be helpful to some of the others trying to interface the Arduino to their existing finish detectors.

Hope that helps, let me know if you have any questions.
Thanks again and the offer to answer any questions.

I found some LEDs at a local electronics shop sayal.com
infrared phototransistor - KID-7404
Infrared emitter - KIE-6305 though perhaps the KIE-7305 might have been better but that is what I could find on the shelves.

I found these specs online.
Image

I might try ErikRuud's breadboard test this weekend.
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

You know the IR Emitters aren't really needed, especially for testing. You can use a regular incandescent bulb.

I have also seen it mentioned that bright white LED's actually emit mo IR than IR LED's do.
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Re: Yet another Arduino based track timer...

Post by hotone »

ErikRuud wrote:You know the IR Emitters aren't really needed, especially for testing. You can use a regular incandescent bulb.

I have also seen it mentioned that bright white LED's actually emit mo IR than IR LED's do.
Thanks for the tips. Where is the line for the start gate switch going in your test set up? It looks just to be hanging there from the pic.
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Re: Yet another Arduino based track timer...

Post by Indy »

I've added an additional page of photos and information, mainly on my implementation of the PDT:

http://www.miscjunk.org/mj/pg_pdt_info1.html ---- some of the zoomed images have extra labels/details

hotone wrote:I found some LEDs at a local electronics shop sayal.com
infrared phototransistor - KID-7404
Infrared emitter - KIE-6305 though perhaps the KIE-7305 might have been better but that is what I could find on the shelves.
That phototransistor looks like it would work. As Erik mentioned you can try different things other than the emitter. I use high brightness white LEDs.
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Re: Yet another Arduino based track timer...

Post by ErikRuud »

hotone wrote: Thanks for the tips. Where is the line for the start gate switch going in your test set up? It looks just to be hanging there from the pic.
I didn't have a switch handy so I was just touching the wire to the ground rail on the bread board.
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