INFRARED HELP...PLEASE HELP

Technical Technical Discussion
1

Hello all. My team and I are sending out an emergency distress call to all F.I.R.S.T. members who might be able to lend a hand. We are running into way too many problems with our IR system and we are using up our fix-it time to hopefully get this issue back into check. We were successful in testing our transmitter at our shop, but we not successful in using it in competition. We are scheduled to make our next appearance at Chesapeake, so time is of the essence. here’s a bit of data on our surrecnt environment, as well as some questions that we really need answered.

This subject is not my back ground so please forgive me if I seem to be giving you useless information. At this point I do not know what is pertinent information.

Our shop is block walled with wood truss roof. Minimum height from floor to just under the truss is 10 feet. The lighting system is a mix of florescent and metal halide lights. To the best of our knowledge we do not transmit any IR or RF in the building or on the property.

The competition arena in Trenton, NJ was a ice hockey rink. The lights in the arena looked as though they were metal halide, but I’m not certain. During any competition round there is 6 teams using RF to control their robot and depending on their autonomous mode may be and more likely are using IR.

I’m told the competition arena in Annapolis is a gymnasium. I’m not shore of the lighting system, but I’m told most are metal halide.

The link provided below is a print of the arena dimensions. On page 2 of the second link it shows a color picture of the foot print of the arena. On page 4 there is a 3D picture of the arena.

http://www2.usfirst.org/2008comp/Drawings/2008%20Field/2008%20Arena_Layout_and_Marking.pdf

http://usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2008_Assets/Manual/6%20-The%20Arena-RevB.pdf

I did witness a test using a Sony remote and a Magnavox remote. All shop lights were on. Both were able to repeatedly activate the receivers LED’s from 100 feet away. Neither of these transmitters were used in Trenton.

Question;

  1.   Does the lighting system have any real effect on the transmitter and or the receiver?

  2.   Is there any advantage to manipulate the existing transmitters signal i.e. mirrors or cones and if so do you have any recommended methods?

  3.   Is there any advantage to increasing the transmitter power and if so do you have any recommended methods?

  4.   Is there any advantage to manipulate the existing receiver  i.e. mirrors or cones and if so do you have any recommended methods?

  5.   Is there any advantage to increasing the receivers ability to receive and if so do you have any recommended methods?

Any help would be very much appreciated.

2

The lap tracking system used on the field is also IR. If your receiver module is mounted anywhere close to the flag pole, you might be getting interference from that and it could completely wipe out your signal. Another important factor is the lighting. What frequency are you running on?

3

What was the problem that you were having? Was the robot simply not responding atall?

-Mike

4

well, our transmitter has a really small range, i guess the root of our problem is the fact that we aren’t sure how to go about increasing the range?

5

Bharat Nain - Our IR board is mounted directly on our flag pole, so I do believe that this is a significant problem. We were able to successfully test remotes up to about 30 feet in the arena while we were still in our pit. Once on the field we were not able to receive commands shortly after the robot left its starting location. We are planning on moving the IR sensor or flag pole at our next regional.

6

Many teams have had significant trouble because or the Lap Counter’s IR output. Most of those teams overcame that problem by shielding the IR board’s receiver from the IR generated by the Lap Counter.
Try making a “hat” for your board to shield it from the stronger IR coming from the Lap Counter and you should be back in business.

7

The above suggestions are correct. We moved our IR receiver much below the flagpole. The IR transmitter on the flag sends a signal upwards so your IR receiver must be mounted at least below that. Then you must shield it. IR signals can bounce off things so they are bound to come back. This tremendously helped us. If possible, I would suggest moving your IR receiver completely away from the flag holder.