Powering your USB Hub at Competition
 

Even though this thread is discussing the control system, I found this to be important enough for its own thread.

Twice our robot became unresponsive, either right at the start of teleop, or shortly after. Pete the FTA at NJ looked carefully at the robot when it happened both times, and in both cases the symptom was no comms from cRio to the wireless adapter.

We strongly believe the solution was insufficient power from the classmate PC to the USB hub for the joysticks.

The solution was to plug both the red and the black USB connectors into the Classmate, doubling the available power for the hub devices.

We have four devices connected to the hub: a joystick, and gamepad, the E-Stop button and the PSOC. I heard from three teams that they had experienced similar issues, and connecting the hub to the classmate twice ( the cable to the hub is a "Y" cable) fixed it. As it did for us.

I can't say how USB affected comms on the 'bot, but after we connected the hub this way, the problem went away. YMMV.

Don

Re: Powering your USB Hub at Competition
 

Remember that the E-Stop button can be removed for FMS official rounds - so that will aleviate some power consumption.

Re: Powering your USB Hub at Competition
 

I thought teams were being encouraged to plug the Cypress directly into one USB hub, and plugging the joysticks and gamepads into the other. As for how this may cause comms issues, since the Cypress device has to be reprogrammed each time it is enumerated. Perhaps power dropouts cause this to happen repeatedly.

Greg McKaskle

Re: Powering your USB Hub at Competition
 

Here's our problem, though sort of off-topic.
How do you recharge your classmate during eliminations when you have to stay on the field the whole time? There is no power to plug into on the driver station area.
This was a major issue for our team as we were scrambling to beg and borrow extra CHARGED batteries.
What happens at CMP?

Re: Powering your USB Hub at Competition
 

Would it be correct to assume that the PSOC is the biggest culprit for USB power consumption?

We have two joysticks and an Xbox controller (but do not currently use the PSOC), and have never had any issues running on Classmate battery power (using only the black plug).

Re: Powering your USB Hub at Competition
 

read this thread

Re: Powering your USB Hub at Competition
 

In these situations on the field that I witnessed, Comms were never actually lost, it just seemed like they were. All statuses were good, but the robot didn't respond whatsoever to any driver controls. Essentially, the Classmate wasn't hearing from the joysticks connected through the hub.

At NJ if I was consulted or found out about it, I had teams plug the PSOC directly into the Classmate and just use the hub for low power devices. A team that didn't use the PSOC, but did have a higher power consumption game controller also had to move that device to a direct Classmate connection.

Using both the red and black USB plugs did not always solve the problem for some, including one of the finalists. They finally went with direct connections for both joysticks. They would have benefitted from just a better redistribution of devices, but under the gun during a match the goal is to just get it working.

Re: Powering your USB Hub at Competition
 

Does anyone know if there is a difference in available USB power between when the classmate is plugged in, or just operating off the battery?

Re: Powering your USB Hub at Competition
 

There should be no difference, according to the USB standard. In order for USB devices to work on an extremely wide variety of machines (from laptops to desktops, Dell to HP to Apple, etc) the standard dictates exactly how the USB port should act, including how much power is available, the transfer rate, protocol, etc. For any device with a USB output, that standard is going to be followed.

Re: Powering your USB Hub at Competition
 

The Targus USB hub became a real problem for us during a practice day with the Fembots. Luckily I had a spare USB hub in my laptop bag and donated it to the cause. When we returned to our classroom, we found a new use for the hub.........Target Practice!.

Re: Powering your USB Hub at Competition
 

If this solves the problems we were having at the Traverse City competition, this will be very, very appreciated. Out of all of the matches played, we were able to play 1 full match completely, and 2 others for a very brief period. After that it appeared that there was no comm. The field manager helped out a ton, and told us that each time a few seconds into teleop, comm was lost. We had tried multiple wireless adapters and locations for it to sit with no avail. We also have a bunch of joysticks connected to a usb hub only connect to one port on the classmate.

After seeing this thread and mentioning it to one of our mentors, he suggested getting a powered usb hub that connects to a normal ac/dc line, but whip up a device to connect it to something like a 9V battery to power it while up at the match stations. Would this provide more available power for the usb hub then getting a y connector and plugging it into both ports on the classmate?

Re: Powering your USB Hub at Competition
 

If you were actually losing communication as indicated by the FMS system, then the issue mentioned in this thread is not your problem. The issue mentioned here is where communication is present, but the robot cannot be controlled using USB devices.

Re: Powering your USB Hub at Competition
 

hmmmmm good point. It wouldn't hurt to do it anyway. It's weird because we stay through autonomous, but as soon as start to move in teleop, controls cut out and all the victors flash and no comm :/ . Could this be a programming error? Our team used LabView this year. As a second backup plan, i got nominated to recode our controls in java to test that out. We're still utterly confused by this problem though.

Re: Powering your USB Hub at Competition
 

This is exactly what happened to us in two matches. In one match, we lost communication immediately after switching from auto to teleop. In another match, we were able to drive in teleop for a couple of seconds before losing comms.
We don't know for sure whether plugging in the second USB cable on the hub fixed the problem because we also switched out the radio and an ethernet cable. However after these modifications, it didn't happen again.

Re: Powering your USB Hub at Competition
 

Huh. Thanks for the input. That may have narrowed down our problem to the power going through the USB hub considering we swapped multiple Ethernet cables and tried 3 different wireless gaming adapters in different locations on the robot.

Re: Powering your USB Hub at Competition
 

We had the same error.

We fixed it by moving our radio away from other electronics and metal, uninstalled the DS, reinstalled the DS (from a different image than the origional), and reupdated the DS (from a different image than the origional).

We believe that we had a bad install of the DS since another classmmate (one loaned to us) worked well.

Re: Powering your USB Hub at Competition
 

My team has found that on the classmates one usb port gets no power or very little and the other one gets practically all the power ( i could better explain this but im extremely tired right now). i advise test both usb ports and label the one that gets the power and use the usb hub on it

Re: Powering your USB Hub at Competition
 

Thanks Mark. Sorry I didn't have a chance to sneak onto the field and say hello.

We did have the PSOC connected to the right-hand port, and the hub on the left hand port, and we experienced the problem (as described by Ethan above). In the pits, we saw the security light flash orange on occasion, and later saw it flashing orange and green very rapidly. I don;'t know what, if anything, these were telling us.
All at the same time, we did swap the ethernet cable, secure the power plug better, and swap out the WGA with our spare. Our WGA was well-located, away from most metal, out in the clear. (Hey, I'm a ham. I know these things)

So, the conclusion is, we have no idea what fixed it, but both 1089 and 25 gave us that advice, and someone asked the pit announcer to say it as well.

Don

Re: Powering your USB Hub at Competition
 

This is triage. Just do whatever works to get back on the field.
If they were dead on the field, I had drivers patch their drive joysticks directly into the Classmate and forget kickers and other controls just to get moving. That usually worked (except when that velcro pulled out that Classmate battery).

I came late when your robot failed on the field and got that yellow warning light, and stood behind you at the practice field after you'd swapped out the WGA and were retesting. You had things well in hand.

I must say your radio placement was indeed excellent and it was very easy to see the status lights when you were on the field.

There was one particular robot that had everything so buried that not a single status light could be seen, and they bolted their cover on so we couldn't get at anything. They sat dead for a few matches and there wasn't a thing we could do to help them.

Re: Powering your USB Hub at Competition
 

Except for one victor. But that's how we troubleshoot, too, so I was pretty adamant when we were discussing component placement.

Re: Powering your USB Hub at Competition
 

We saw a similar problem in one of our matches that was solved by unplugging and reconnecting the field cable. It might be related to our classmate not actually latching Ethernet cables though, which was causing us to lose fms connection (yet another perfect place for electrical tape)

Re: Powering your USB Hub at Competition
 

In response to some of the problems with the USB hub, Half way through build season ours stopped working just about half of the time. What I mean by not working, is that nothing could be recognized by the Classmate. we solved the problem by purchasing a new USB hub, and since then, we have not had any problems.

On one occasion, we were at a pre-ship mini regional and we could not get the Joysticks recognized during the last match of the day:mad: , the problem was solved again by replacing the hub. After discussing with other teams, we discovered many were having this exact same problem with the hubs.

I would recommend all teams to have a spare in case theirs goes down before a match! (Theres nothing worse than a dead robot!)

-Mcgurky

Re: Powering your USB Hub at Competition
 

We were using both red and black wires to power our joysticks since the beginning of build so I am unaware of what types of problems occurred. What usually happened? Is this what was happening with 1089 and 816, they told me one stick just stopped functioning.

Re: Powering your USB Hub at Competition
 

Having both red/black USB hub cables plugged in did not always prevent the controls from failing.

816 is a case in point.
They did everything right, but still died.
Their final solution was to plug just their drive joysticks directly into the Classmate ports, so they could at least drive. They had to give up their kicker and other controls though.

It seems the hub or it's cable is a major failure point and it's difficult to predict if a team will have trouble with it or not. Bring a different model to competition as a safety backup.

My suspicion is it's really a USB cable or connection problem.

Re: Powering your USB Hub at Competition
 

Exactly!!!
For less than $10, you can save yourselves a ton of headaches.

Re: Powering your USB Hub at Competition
 

We were the Finalist Referred to in Mark's post.

Our control board included 2 Joysticks and 8 Push Button Inputs, all of which were plugged into the USB hub, which was then plugged into the Classmate using both the Red and Black Wires. Throughout the day our joysticks dropped in and out but I don't believe we ever lost our buttons. I'm going to have our programmer and Electronics Mentor Re-Wire the PSOC Board and check all of the connections for any shorts or anything that would cause it to draw excessive power. For Philly we're going to try plugging our Joysticks into the Hub and then into one of the USB Ports on the Classmate and then Plug our PSOC board into the Other. Hopefully this'll resolve our problems.

Mark, Thanks again for all of your help throughout New Jersey.

Stogi, our Primary issue stemmed from USB Hub problems and I believe 1089's did as well.

We also had a Faulty C-Rio Power Connection that was causing our C-Rio to Short out and Reset on Saturday...

Re: Powering your USB Hub at Competition
 

All of you were a pleasure to work with and made it a pleasure for me.
Troubleshooting is the most fun for me, and a working robot the reward.

Sorry I can't make Philly, but I'd recommend you also purchase a different model USB hub as a backup.
I suspect both the USB power cable as top of my suspect list, and the USB hub itself a possibility. If you get a spare hub you can test with both a different cable and with a different hub.

If it happens to you on the field again, the first thing I want you to try is hit the F1 button on your Classmate.
Let me know if that helps at all. It'll make the Driver Station close and reopen all the joysticks (thanks Greg).

Re: Powering your USB Hub at Competition
 

Actually, there could be a difference. The USB standard indicates that a device may initially draw only 100mA from the port. The device must request, via transfer on the bus, if it wishes to exceed that limit, and may request up to 500mA. The host can deny this request if it wants (due to not enough power available etc). I've never seen this actually happen, but certainly seems plausible that a small netbook with a tiny battery might deny >100mA requests when running off battery.

Re: Powering your USB Hub at Competition
 

I'm actually going to talk to my Programmer tonight about buying a new USB Hub, I don't think we're going to use our current one in Philly, unless I continue wearing it as a good luck charm. (I wore it around my neck for the Elims in Jersey and we ran every match after I put it on)

Re: Powering your USB Hub at Competition
 

Just to add a little bit of information as to what happened with us 1089.
I apologize up front for the length of this post....

We ran all day Friday fine, and most of the day on Saturday until we experienced this problem. I'm still not 100% sure what the root cause was, but it is my belief that a combination of Low Classmate battery, 2 Joysticks, PSOC (4 buttons box) and the USB hub all being powered by a single USB port caused the USB port to not be able provide enough power to drive everything needed. This caused the joysticks to not respond and hence unable to drive, even though some buttons worked.

Connecting the RED and the BLACK connectors as a triage stop gap idea from the USB hub to two ports on the classmate cleared the problem. This solution for a short explanation allowed power to be drawn from BOTH ports to cover the power requirements of the attached devices.

Looking deeper into this issue, I've come to the conclusion that for some teams it may be wise to balance the load from your controls between the two USB ports on the Classmate. Some other Joysticks have a higher power requirement than those ATTACK-3 provided in the kit.

I do not yet have the milliamp draw numbers for the ATTACK-3 joysticks or the hub, however the PSOC is capable of drawing up to 400mA. The PSOC is divided into quadrants each able to source 100mA.

Given that a USB port can provide up to 500mA total, it could be very possible, that a combination of PSOC, higher powered Joysticks, hubs, etc could exceed the available power on a single port.

That's the best theory and explanation I have for what is happening.