[archiver]

Posted by Thomas A. Frank.

Engineer on team #121, The Islanders/Rhode Warrior, from Middletown (RI) High School and Naval Undersea Warfare Center.

Posted on 2/16/2000 1:39 PM MST


In Reply to: Re: re: cameras posted by Dodd Stacy on 2/15/2000 5:55 AM MST:



Hello All;

Having been the team that pioneered RoboCam back in 96 (or was it 95, can't remember now), a few words of advice:

1. Yes, check with Eric for approval. Radio interference would be a bummer. Besides, you'll want to provide FIRST with a receiver so they can put the video feed up on the big screen, so they need to know what to expect. Which reminds me, bring some RF adapters - last time I did this, my stuff was RCA jack, and they all were using BNC's. Fortunately, we had adapters available.

2. A camcorder (no RF transmitter) shouldn't require approval, but it's only an email, so you might as well ask anyway. This, BTW, is a great idea, as most newer camcorders have electronic image stabilization, a real plus.

3. The range of most TV 'extenders', X-10's stuff, Rabbit's, etc is VERY poor, and the hardware is very much suseptible to impact/vibration induced harmonics. In short, the video images tend to be fairly poor...ours were always described as having that 'NASA first man on the moon look' to them. Don't be surprised by drop outs, cross hatches, and other noise related artifacts. And don't be surprised by the level of vibration apparent in the pictures - yes, your machine is vibrating that much! Makes you appreciate loc-tite and nylock nuts all the more once you see how badly these machines vibrate. FIRST is a surprisingly harsh environment.

4. Related to the above, all the cameras and transmitters are VERY sensitive to supply voltage. If you are thinking about running the system off the robot's battery, you are setting yourself up for possible disappointment. The first year we used a separate battery for the video system (it needed 18 VDC); the next year I used robot power and it was quite a disappointment (I later noted battery voltage drops as low as 7 VDC under hard acceleration); after that I went for a DC-DC converter and a large cap for holdup, which worked better. But it's still not perfect.

5. If you use a really small camera, put it on a servo so you can swivel it - pan and tilt are great features, which can be run off a spare output on the RI. I used to have to use a separate R/C rig, which was very inconvienient, and which confused and annoyed lots of people.

6. Protect the unit. It would be unfortunate to see it destroyed by another robot hitting yours.

7. If it is a separate small camera, try different locations. There will probably be a location on your machine which is 'perfect' for the on board view, you just have to find it...one year ours was on the top of a vertical structure, and was nicknamed 'crotchcam' for the, ah, unique perspective it provided...putting the camera lower down might have been better :-)

8. Have fun with it! Drive your machine into the office of the head of your sponsor, and surprise him/her with a visit.

Enjoy!

Tom Frank