Radio cuts out, student's foot run over

[ntroup]

Originally Posted by Eldarion

(Our team ran through a testing procedure on almost all 40 channels; we have the results if anyone is interested.)

I am quite curious how you did this? By default, the OI will only allow the use of 6 channels.

From the OI Reference Guide (from ifirobotics.com)

Channel 40 is the default channel and will always be selected unless a different channel is selected by changing the MSB on the Team Number dipswitch. Channels 01, 04, 13, 22, 31, or 40 are available if the MSB Team Number dip switch is Open (see section 8 for details on team number positions).

The rest of the channels, to my understanding, are only available through the competition port, which is an undocumented protocol.

-Nate

[Eldarion]

Originally Posted by ntroup

The rest of the channels, to my understanding, are only available through the competition port, which is an undocumented protocol.

A previously undocumented protocol. I figured it out over the summer last year.
So I now have a homebrew field controller!

[ntroup]

Originally Posted by Eldarion

A previously undocumented protocol. I figured it out over the summer last year.

Interesting. Does this involve talking to the OI through its competition port to set the channel number, or configuring the modems themselves?

I know there has been lots of discussion in years' past concerning the information going between the OI and the Arena Controller (through the Competition Port), but that conversation always led to discussions of how 'GP' it would be to reverse engineer that information.

-Nate

[Eldarion]

Yes, I talk to the OI through the competition port (I emulate an Arena Controller). As I am not releasing any info on the protocols or pinouts, I think it is acceptable as far as GP goes.

[Eldarion]

I guess they only tested 4 channels; sorry about that!

Here's the info anyway:
Channel 1 tested for 10 minutes, cut out 14 times.
Channel 14 tested for 5 minutes, cut out 6 times.
Channel 20 tested for 5 minutes, cut out 6 times.
Channel 38 tested for 5 minutes, cut out 4 times.

[mluckham]

We have found a problem also that causes the robot to take off, when the dongle is switched from Autonomous/Kill, to Operator Control mode.

It seems the first value read from the joystick was 0 (which, when the value was copied to the Victor, made the motor go suddenly full-speed). After that the joystick values were read correctly. This was with Master Code V12, we have since upgraded to V13.

At first we put in a 1/2 second delay in Operator Control mode, before reading the joystick the first time. It seemed to work, but as code was being developed we had other accidents where motors were set to full-speed.

So we put the Victor output for left-side and right-side into two C procedures. The procedures check for legitimate PWM values 1-253. Joystick input procedures were similarly modified, to avoid the extreme values 0 or 254.

In this way, a 'glitch' or coding accident cannot send 0 or 254 to the Victors.

This has solved our problem.

[Samara]

our team had a similar incident which was mentioned in another post but yeah scary stuff because it came at me, one of our mentors had to dive infront of it.

[Joe Ross]

Originally Posted by Eldarion

Also, from our experience, this problem will only get worse in competition mode, not better! Apparently, at lower channel numbers, the radios are worst. (Our team ran through a testing procedure on almost all 40 channels; we have the results if anyone is interested.)

Can you confirm that the radio was mounted per IFI's recommendations? http://www.ifirobotics.com/forum/vie....php?p=833#833. Specifically, team 179 found that the radios had to be 6-8" away from metal.

[paulcd2000]

we too have had many problems with the V14 firmware, and some with the V13. We've had the robot continue for a full second after disabling with V13, and more than that with V14

[grantf]

The following is our compliance with the IFI radio recommendations.

You need to be running Master Code 13 when using the new 2007 Radios and a 2006 or 2007 OI.

We were running the v14 Master code when the robot took off.
We are using the 2007 OI and RC only.

As for intermittent stalls; make sure all power connections are tight, from the battery, through the circuit breaker panel and to all devices. Pull on all your power connections. Repair any that are loose or come free. It is best to solder all wire connections; a crimp connection can come free.

We are using quick connects (spade connectors) for all 20 amp lines.
These connectors are from this year's kit and fit very tightly.
All connections were checked.
A charged backup battery was in use.
A fresh main battery was installed only seconds before the incident.

Intermittent stalls can be from breakers tripping. If you have all green LEDs on the RC unit, you do not have a radio problem. If your motors are drawing too much current, the breakers will trip and the motors will be dead for a few seconds until the auto-resetting breaker has reset.

There were times when we only saw the Valid TX light on the OI go on.
Other times the No Data/Radio light was solid red.

If you see the RC’s Radio Modem LED flashing Red, the RC unit is not receiving radio data. This can be caused from Interference from another source, bad Radio Modem Cables, Radio Modems (OI or RC), or in rare cases the RC or OI unit.

Didn't really see this because we were busy chasing the robot.

For best radio reception, follows the guidelines: 1) the RC and OI Radio Modems should be mounted high and perpendicular to the playing field. 2) Both the Radio Modem Case and the moveable Antenna should be perpendicular to the playing field. 3) The Radio Modems and DB9 Radio Modem Cables should be kept as far as possible from any High Current Wiring, Motors, and Victors ….etc. 4) The Radio Antennas should not be touching any other surface. 5) The Radio Modem Case and Antennas should not be shielded by any metal structure. 6) There should be a “Clear Line-of Sight” between the RC and OI Radio Modems case and Antenna. 7) Interference from another radio source can be solved by changing to a different practice channel.

1. Check
2. Check
3. Check
4. Check
5. Check, I think... the RC Radio Modem is mounted vertically, about 2 feet off the floor, very near 2 aluminum support colums (1 inch square AL tubing, about 3.5 feet long). However, the RC modem is not "sheilded" in a Faraday-Cage sense... most (90% or more) of the antenna's field of view is unobstructed.
6. Check
7. Check, but we haven't tried another channel yet.

I contacted IFI just the other day and reported this issue (robot taking off while apparently disabled).
They said that in 5000+ systems shipped, they have never once come across this issue.
IFI is waiting for us to reproduce the problem.
It would be great if other teams who are experiencing radio issues could try to produce this problem as well.

Thanks for all the feedback,
Grant

[IFBen]

This happened to me at our team sponsored dinner/fundraiser. Our battery got so low we went to turn it around and wheel it back to the front of the hall and it spazzed and ran me over!

[Matt Krass]

Originally Posted by grantf

I contacted IFI just the other day and reported this issue (robot taking off while apparently disabled).
They said that in 5000+ systems shipped, they have never once come across this issue.
IFI is waiting for us to reproduce the problem.
It would be great if other teams who are experiencing radio issues could try to produce this problem as well.

Thanks for all the feedback,
Grant

Did they really say that? That seems a bit like "You're making it up" to me..

..anyways, would it be possible to test this with older radios/firmwares from last season? Sorry if you already tried that and I missed it, I'm kind of in a rush here.

[aaeamdar]

Originally Posted by UlTiMaTeP

He stated the radios were mounted correctly. The radios this year for many teams are defective. The radios need to get an RMA'ed and replaced chances are. You are not alone, the majority of the teams in my area are having the same radio cutting out problem.

We are having a similar problem. I started a thread including a poll (not many people saw it, but still...). It is here: http://www.chiefdelphi.com/forums/sh...ad.php?t=54106

I am getting SO frustrated with IFI. The very least they could do would be to acknowledge that there is a problem.

Anyway, hopefully we can find an easy fix for this (though that doesn't seem likely).

Paul

[Eldarion]

Originally Posted by Matt Krass

Did they really say that? That seems a bit like "You're making it up" to me..

..anyways, would it be possible to test this with older radios/firmwares from last season? Sorry if you already tried that and I missed it, I'm kind of in a rush here.

We are using the 2006 radios on the 2007 RC with FW 13 with no problems.

[whytheheckme]

Originally Posted by Eldarion

We are using the 2006 radios on the 2007 RC with FW 13 with no problems.

Yeah... We have a set of 2006 radios that work beautifully. The 2007 radios crap out all the time. And how do they expect you to mount your radio so it is '6-8"' completely away from metal? Do they want a foot long piece of plywood sticking out from the middle of your bot in a direction away from any other part of the bot that doesn't violate the height limit and in a place where the cord can't get caught in moving parts / get run over by robots climbing up your ramp?

Why do the old 06 radios which are RS-232 have no problem, while these new larger RS-422 radios have all sorts of problems.

Also, they wont let us use the old ones. WHY???

Originally Posted by www.ifirobotics.com/radio_modem.shtml

Note: These radios are new for 2007 and can not be used/interchanged with previous radios/modems.

Jacob