Spikes and solenoids randomly hiccups when controlling over wireless

[techbeast34]

Hey guys, so our team has a small problem that bugs us a tiny bit. Whenever we are connected to our robot over wireless, the robot "hiccups" and in that period, the spikes and solenoids on our robot temporarily disable. This happens sporadically and the problem does not appear when tethered. We've tried using another D-Link, tried swapping the cRIO, tried swapping the driver station, and swapped out each individual module on the cRIO. The problem occurs even without the Spike connected, and this can be told by the Digital Sidecar indicator LED. So far this hiccup only occurs in our latest robot, our Rebound Rumble robot does not show any symptoms of this happening at all. Again, this only happens when connecting over wireless, and not when wired to the robot. Any help will be greatly appreciated! Thank you to anybody in advance.

[AustinH]

Happened to us too on our practice bot. Leading theory is that there's too much interference where the radio was initially placed, so our final design has our radio placed in a much more open spot with fewer large power consuming devices nearby. Can you guys post pictures of your setup?

[Joe Ross]

The Driver Station log viewer can be very useful for diagnosing these types of problems.

[Alan Anderson]

Originally Posted by techbeast34

...this only happens when connecting over wireless, and not when wired to the robot.

Do you tether through the router? If so, wired vs. wireless is the only difference, and you probably don't need to investigate anything else.

Is there anything electrical near the D-Link router? One of the biggest interference-causing culprits I've seen is the 12v-to-5v converter. I've encountered several teams who had succumbed to the temptation of mounting it right against the router, which turns out to be a very bad idea. Jaguars are also powerful sources of electromagnetic interference (Victors don't seem to be as much of an issue, and I've not had enough experience with Talons to be able to say one way or the other).

[Jared]

We had this last year, and it drove us crazy when the robot would start clicking randomly without logging any errors. The problem turned out to be the cRIO power connector. If you wiggle the cRIO power wires (at the cRIO and the PDB), and it hiccups, then try replacing the connector.

[techbeast34]

UPDATE: Started measuring packet loss to the cRIO through the DS Log, and found out that whenever the hiccups occur, packets are lost, so we confirm that it is packet loss. We ran the "ping" command in such a way that it pings infinitely until we stop it, and we also saw that the lost packets were actually returned, just after a significantly longer time. We fiddled around with the router settings by changing the bandwidth to Auto 20/40 MHz, changed the WiFi channel being used, isolated the DS connection by disconnecting the other dev laptop, and updated our Driver Station's Wi-Fi drivers. We've also taken away the D-Link from the robot and the hiccups still happened, so the idea of electronic interference is starting to become less plausible, but I'm still considering it. We turned off all the power saving settings for our DS too. Any more ideas of what might be causing this hiccup?

[RufflesRidge]

Have you tried swapping in last year's radio? It's possible that the radio itself has a bent antenna or other abnormality that's causing the issue.

[Alan Anderson]

Originally Posted by techbeast34

...changed the WiFi channel being used,...

Have you run a Wi-Fi channel scanner tool? Something like inSSIDer should be able to show you how congested your 802.11 band is, and perhaps let you choose a channel with little interference.

[co1inw]

Hello,
We are also having the same problem with our DLink. We have tried moving the DLink, changing Ethernet cables to the cRio, and using other DLinks from previous years. We even tried using a DLink with only two computers connected to it and nothing else. When we tried to ping one computer from the other, after a minute or so, the ping response would be very slow for a few seconds, then go back to normal. When we did this same ping test while the cRio was connected, the slow ping response corresponded to the hiccups on the robot. The hiccups will happen anywhere from a minute apart to 5 minutes apart. I have attached links to some images from the Driver Station log viewer that shows the hiccups happening. the blue spikes on the graph show packet loss.

Ping test image with the computers

Driver Station Log

Zoomed in hiccup on Log Viewer