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      04-23-2014, 12:38 AM   #1
regular guy
Drives: Sprint car
Join Date: May 2013
Location: California

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Designing A Next Generation Track Camera Setup

I wanted to share something I've been working on the the past month. This is only a prototype, but it's good enough to share. Many people have seen remote controlled airplane and helicopter rigs. But have you ever seen something like that in a car at a track event?

Most of these set up are gimbal controlled camera's. A gimbal is a gyro sensing, auto leveling camera mount. As you go around corners, over bumps, the gimbal will auto level and always keep the horizon level. I wondered if RC planes and helicopters can deploy a gimbal, then why not use one in an HPDE or Roll Race events? Why not take it one step further and make the whole thing remote controlled while sitting on the sidelines watching streaming video and controlling the cameras as they race? Why not?

The goal was to create a fully remote controlled race car camera system that could stream video to us in the stands or sidelines. From there we could control the camera's to pan the camera as cars were passing each other. If it works, it should make some great racing video.

So I thought I'd give it a try to see if I could make it work. There's lots materials to buy and lots of prep work.

There are plenty of gimbals that are purpose built for the GoPro camera's. They are easy to find on the internet.
1. The Tarot T2D is probably the most popular. I used this for a two-axis gimbal pointing straight out the front of the car.
2. A three axis gimbal "Arris CM-3000" available in China. Also specially made for the GoPro Hero 3. This is the unit I used to control and pan the camera.

Two GoPro Hero 3+ Black Edition. The Black Edition has better resolution and more features. It's not easy to make these camera's turn on/off, start/stop recording via remote control. You must take them apart and modify them to do this. I made a "HowTo" video that will be soon posted on YouTube. Contact me for details if interested.

Remote control:
The FrSky Taranis X9D seems most popular, so this is what I bought.

Lost of electronics:
I also wanted to power the GoPro's while using them so I wouldn't depend on the GoPro batteries. To do this, you need 5V/1A voltage regulators. PWM controlled relay switches are required to operate the modified GoPro's. Everything else is off the shelf Turnigy components. There was at least 60-80 hours of custom wiring because I was constantly finding some limitations to wire thickness, flexibility (rigidity) that affect camera rotation. I redesigned the unit two times before this final creation.

Video transmitter/receiver:
Using 1.2 GHz transmitter/receiver. I'm still experimenting with this area, so it's not yet settled. I might switch to a digital system.

~ $1500 for everything (assuming my time is free)
~ $3500 for everything (if you don't think my time is free)

The Limitations:
I worked on this for weeks before the Shift-S3ctor event. I worked on it literally until I went to bed the night before. I had no time to test it or discover the limitations. Even if I found limitations, time was out and I couldn't fix it. As I found out, there are some limitations.

1. The range of the RC controller wasn't good enough.
Even though the RC controller is supposed to be good for a mile or more, that's not what I got at the event. I'd say it was good for 500 yards, and nothing more. To fix this, I'll switch the controller to a UHF setup called DragonLink. The DragonLink plugs right into the RC controller and is seamless integration. This unit is good for 25-40 miles. DragonLink should arrive next week. Cost: $270.

2. The video transmitter couldn't transmit far enough.
Even though I had a 1W transmitter and 10db gain antenna, it still wasn't strong enough to get past 300-400 yards. Because of this limitation, we had to come up with a creative solution. To solve this problem, I placed my son with the RC controller and streaming video receiver in the car racing Drew (DLSJ5). Placing my son in the car would guarantee real-time control of the cameras without any drop outs while operating. I investigated this video limitation and discovered that professional systems are cost prohibitive (starting at $6k, and up to $100k). But there may be a middle ground. An entry level professional digital video transmitter/receiver cost about $1500. This system is designed specifically for race cars. But it's only guaranteed to transmit a little over 1/2 mile (1000 yards). This spawned a hybrid idea of using the digital system and strategically place the digital receiver 800-1000 years down the track. The digital receiver would feed my 1.2 GHz analog transmitter. I could then use a high gain directional antenna pointed directly at the 1.2 GHz analog transmitter. This hybrid approach should guarantee 1-2 miles of range out of this design. But before I consider more expenses like the digital video system, I need to exhaust all other possibilities and debug the system I have.

3. Some glitches during power up/down cause the relays to trigger, which causes the camera's to turn on and record without my permission! This is more annoyance than real problem. But I have some ideas to fix it. I actually think the DragonLink UHF RC adapter might fix it because I suspect the bug is in the Taranis receiver.

4. The Tarot T2D gimbal didn't work as well as I had hoped. It may be great for quad copters and airplanes, but in a car I found that it couldn't recover fast enough to g-force changes going around corners. The Arris CM-3000 3-axis gimbal seemed to work much better than the Tarot T2D. Arris also makes a 2-axis version: CM-2000. I already ordered one, and it arrives tomorrow.

The Results:

The Race:

The results far exceeded expectations even with the design limitations we discovered. The video speaks for itself. The video is perfectly smooth, the gimbals are doing their job of auto-leveling, and it's real fun to watch the camera panning perfectly smooth as the cars pass one another. This is definitely a technology worth perfecting. Hopefully it can be low cost enough that hard core track rats can afford it for themselves.
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