[FTC]: Losing Control During Competition

[skatefriday]

We spent a few months a couple of years back trying
to isolate a short only to find it was the stock battery
connector. Replaced it with powerpoles and the short went
away.

So, yes, powerpoles _everywhere_ are pretty much a mandatory
requirement for reliable operation.

[TheThings5926]

Static can be an issue. I know our team had a lot of issues (4 out of 6 rounds lost communication) at our regional tournament, some of which were static. One of our team members has built a static detector which we have found that our tracks creates a lot of static (we use the tetrix tank treads). We have also found a anti-static solution that you can put on the robot. I am not sure what exactly is in the solution but I can find out.

Best of luck

Matt,

The Things, 5926

[F Elliott]

Skatefriday... We crossed the Rubicon and converted batteries and charger to Anderson Powerpoles on Thursday.

Matt... Thinking about the static electricity issue made me realize

1. We have too much USB cable coiled up in the bottom of our robot. We will get a shorter one from USB Stuff, maybe with right-angle ends for strain relief and put some ferrite chokes on the cable.
http://www.usbstuff.com/cables.html

2. Wonder if the NXT and USB cable's close proximity to one of our drive motors could be causing an induced current noise spike in the cable as the motor is turned off and on.

[cgmv123]

Originally Posted by F Elliott

2. Wonder if the NXT and USB cable's close proximity to one of our drive motors could be causing an induced current noise spike in the cable as the motor is turned off and on.

Motors can definitely interfere with wireless signals. FRC teams are instructed to keep their robot radios away from motors (especially CIMs) and other electronics. Up high and away from metal is a good rule of thumb.

[F Elliott]

Samantha module is high and isolated. However, the NXT and it's USB jack are very close to one of our drive motors.

[cgmv123]

Originally Posted by F Elliott

Samantha module is high and isolated. However, the NXT and it's USB jack are very close to one of our drive motors.

Move the NXT away from the drive motors and see if that helps.

[skatefriday]

Originally Posted by F Elliott

Skatefriday... We crossed the Rubicon and converted batteries and charger to Anderson Powerpoles on Thursday.

This has the added, ahem, 'downside' that your chargers
can no longer be loaned out at tournaments.

Then again, conversely you can't leach off of another
team's charger.

In hindsight, saving the molex connector and attaching power
poles to it for compatibility purposes and then just packing
that away in your travel kit is probably a good idea.

[Sasha]

Originally Posted by skatefriday

This has the added, ahem, 'downside' that your chargers
can no longer be loaned out at tournaments.

Then again, conversely you can't leach off of another
team's charger.

In fact, a fair fraction of the teams have done the same and equipped their chargers with powerpoles... so you can share with those teams.

[F Elliott]

We cut 6" off the charger end and attached a Powerpole giving us a little Molex to Powerpole adapter cable so someone can charge a Molex battery using our charger if needed.

The end we clipped off the battery was too short to make an adapter for the other end.

[skatefriday]

Originally Posted by Sasha

In fact, a fair fraction of the teams have done the same and equipped their chargers with powerpoles... so you can share with those teams.

I haven't seen any teams doing this in either the Los Angeles
or San Diego qualifiers we've competed in in either of the last
two years.

I'm pretty sure it will catch on though as it's a vast improvement
over the stock connector.

[WIREDFTC]

We haven't done it yet because of our budget, but when we get enough, that is the first thing I want to do, many teams in Missouri use Power Poles, and they are much more reliable then the stock Tamiya connecters on the battery, because the female end expands and the male end doesn't have a good connection any longer.

[pyroslev]

Originally Posted by TheThings5926

We have also found a anti-static solution that you can put on the robot. I am not sure what exactly is in the solution but I can find out.

If you can, please share it. I'm always looking for something to tell teams to try.

[safiq10]

At the killeen competition this weekend the connection went terribly! during one of my teams matches the teleop drove for 1 second and then went on the fritz for us. While in finals and semi finals our sister team was having their robots going in circles and to prove a point they all put down the controllers too and it was spinning!

[VashonRobotics]

Towards the end of our season one of our teams had the same problem. We recorded the problem with a video camera following it around on a practice field until it failed. Then we played back the video and discovered that the Samantha module lost power for a brief moment - all lights went out. Then it came back and was rebooting. In the meantime the NXT was stuck on the last command given so if it was turning then it just spun in circles. Sometimes when the Samantha module came back up and connected to the FCS again control returned and other times it didn't. The problem was easily duplicated over and over.

The Samantha module's power was coming from the power buss on one of the motor controllers. After careful inspection we found many of the wires connected to the motor controllers were tinned. This is bad. We found posts on Delphi and Internet that solder can deform or (cold creep) over time and become loose when in a clamp connection. After going through and cutting off all the tinned ends and inserting bare copper and clamping that down in all the motor controllers the problem could not be duplicated and this problem never happened again for the rest of the season. So our conclusion was that this problem (at least for us) was caused by loose connections in the motor controller wire clamps.

Nice tool that helped us with this troubleshooting process was using video. We couldn't have seen that it lost total power without it because it happened so fast.