Our prototype Instant Replay system

Discussions on buying or building timers, solenoid start gates, light trees, weigh scales, and other race related electronics.
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Pack200SC
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Our prototype Instant Replay system

Post by Pack200SC » Sun Feb 09, 2014 8:15 pm



After building our own timer using a Netduino platform, I turned my attention to building an arduino based instant replay system. At first, my thought process was to entail pulling the video from a high speed camera and then re-encoding it to play back in slow motion, however that solution became expensive and impractical for short races. Then, it occured to me, my family has a four year old Sony CX500 Handycam which can be controlled via infrared. A little coding later, and I've come up with this working prototype. The video stays completely on the camera, thereby not requiring anything other than the arduino, a few LEDs, photocell and laser. There is less than $35 in electronics in the whole setup.

Also, since this video was recorded, I have discovered an extra special nicety about this particular camera. It has a 3-second "Smooth Slow Record" feature, which makes it a truly high speed camera, capturing approximately 240fps for 3 seconds, which of course is plenty of time to catch a derby finish. So, instead of deleting the video after each race, I'm keeping each 3 seconds of high-speed footage, which is approximately 50MB of space. The 32GB on the camera should allow us to record over 600 races, which should be gracious plenty! When the 3 seconds of "Smooth Slow Record" footage is played back in "slow" scan, it takes 60 seconds to play, giving us a 20:1 slowdown. The cars practically crawl across the finish line at this pace, making it a fairly good backup plan in case our track timer breaks. The fact that the unit is completely automated makes it even better.



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gpraceman
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Re: Our prototype Instant Replay system

Post by gpraceman » Mon Feb 10, 2014 1:59 am

That is a pretty nifty hardware solution. Have you tried it with a track yet? How much latency are you getting before the camera responds to the IR commands?


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Pack200SC
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Re: Our prototype Instant Replay system

Post by Pack200SC » Mon Feb 10, 2014 7:09 am

No, not yet. Our races are not until next month so I don't have access to the track. However I have tested it at home with another high speed camera, and I'm seeing less than 1/25th of a second latency. Even if it had been higher, it could have easily been overcome by moving the laser trigger further toward the start gate. Plus, this camera also had the ability to record the PREVIOUS three seconds as well, so in the end, we may even forgo the laser line completely and trigger off the timer.

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Pack200SC
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Re: Our prototype Instant Replay system

Post by Pack200SC » Tue Feb 11, 2014 4:04 pm

Completed!




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Stan Pope
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Re: Our prototype Instant Replay system

Post by Stan Pope » Wed Feb 12, 2014 11:28 am

Pack200SC wrote:Completed!
Nice work!


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