VEXnet 2.0 Impressions

I recieved my vexnet 2.0 keys about a week ago and wanted to share my experience with you. So far they have worked very well.

Firmware Update:
There was some trouble getting the new firmware on the cortex to work with the robot c software. Make sure that you update both the ifi Firmware utility and robotc, easy c ect before you try to do the upgrade. I had to flash the ifi firmware twice before it worked, so if you don’t get it the first time just try again and it will probably work. Don’t forget that the controller also needs to be updated with new firmware.Make sure you re-sync the controller and the cortex with an usb a to a cable after the update. I also tried switching between vexnet 1.0 and vexnet 2.0 keys and there did not seem to be any problems.

Note: at this time wireless programming with vexnet 2.0 is not supported.

It is much faster than vexnet 1.0 to connect. It seems to take about half as long to connect on startup. I have had 0 connection losses so far, but we will see how they hold up in the long run as long term reliability was more of an issue with the old keys. I will update in a little while when i have had more experience with them.

New Retention Mechanism:

The rubber on the sides seems to help to hold the key in the controller much more than it does in the cortex. It holds very firmly in the controller, but the cortex is a different story. It is better than the old keys, but it is still not where i think it should be. There is still a lot of room for the key to move out of the cortex. It is hard to explain, but it is in the direction perpendicular to the direction in which you insert the key. It is more secure but i am still going to tape it in for more security. The attached pictures show the rubber that was added to the new keys to help hold them in.


The connection between the plastic case and the circuit board seems more sturdy on the new keys. I have not had them for very long but the connection feels much more substantial. I haven’t opened on up yet to look, but i may post that back later.

Other thoughts:

the other interesting thing is that the robot light on the controller does not seem to flash red without a backup battery.

Overall good update, but still not as good as they could be, but hey there is always room for improvement. The retention still needs some work on the cortex, but it is hard to improve without modification to the cortex which is obviously not a good option. The connection and interference seem to be much improved compare to the previous keys. Good work vex.



I anyone has questions just let me know :slight_smile:

Have you used the new keys during a competition yet?

Does the connection reset when plugging into a field control system like the 1.0 keys?

Thanks for that, helps out a bunch

We have been Tournament champions, and Tournament Finalist using these new keys. They work great, stay cool, and use less battery which makes a huge difference with joysticks! We are used to going to tournaments with 2 robots and 36 AAA batteries, while we will continue to keep plenty of batteries charged and with us, we do not sweat it any more.

Several teams in MI have tried these keys in competition and they suffered rampant disconnect issues to the point where their robots could only move for several seconds of their matches.

Well that’s not good news. Did teams using the VEXnet 1.0 keys also suffer disconnects? Did the teams with the VEXnet 2.0 keys have problems in the pits as well as during matches?

We have used them for almost two full weeks. We also had a few issues with getting the firmware updated. After that however we have yet to have a single disconnect! Connection time also seems to have dramatically dropped!

Overall we are all in on these keys!

Please contact our technical support team, ASAP. We’d love to hear more about this so we can try to understand what happened at this event.

We got these new keys two competitions ago and used the disk utility (not RobotC) to upload the new firmware. With our old faulty keys, we spent half our time in competitions dead on the field. Since we got the new keys, we’ve had no drop-out problems, and we managed to win a tournament. Also, because of the snug fit achieved by the rubber fins on the new keys, we have not felt it necessary to tape or rubberband the keys in. So far, for us, these keys look like a winner.

We have had better luck but am hesitant to say 100% good. We have not had vexnet drops but we are also the only one running the new keys so we’re the only one on the frequency I guess. We’ll be ordering more keys but still wondering where that trade in program is…

So the issue we saw…

We had a motor unplugged as well as a bad program where the arm started lifting under the bridge. Bad things ensue. So I imagine the PTC’s tripped pretty good or the Cortex tripped. No joystick response for a few seconds.

However, all the lights were still green during our drop out. So we don’t know if we got hit by the motors or the cortex. But since the drive motors did not move, I imagine it was the Cortex. But the Cortex is supposed to have some light pattern to show the cortex tripped.

Can the guys at Vex please do the following test? I do not have the oscilloscopes and spare cortexes to try this.

Load some motors up to the point of tripping. Maybe put some current monitors on the motors and get it to trip and watch the lights and use some bench supplied power so a battery is not an issue.

Can you do a motor based PTC trip versus a cortex level and see what happens to the lights?


I am not sure how your program works, but we had a similar problem in one of our matches where a bucky ball got stuck underneath the lift and it couldn’t go down all the way. As we were going down until limit switches were pressed, which they never were in this instance, the program got hung up on that one command, and nothing else worked. I would imagine the thermal fuses tripped in the motors, but they still never pressed the limit switches, so the program couldn’t continue to the other parts.

The cortex has no idea if either of its internal PTCs trip, the leds should indicate a low main battery, but not a tripped PTC.

Saw 1 team outfitted with these keys at a tournament 2 weeks ago, just outfitted 2 more MS teams in my area today. Very sturdy and I love that the connections drop less. I’ve yet to examine them heavily in terms of connection to field, but the one team that competed in a tournament was tournament champions so that’s one thing.

Seems to be better than VEXnet 1.0 by a lot! :smiley:

Not entirely sure of that yet but we will see how this weekend goes. But not until I see 50 robots at a tournament all running 2.0 will I say it’s truly better. And using the Robot C debugger wirelessly without frequent drop outs when that comes out too.

We gave our one set of 2.0 keys to another team that updated the firmware for a match this past weekend. They dropped Vexnet 1.0 in the semi-finals so we gave them the new keys for the finals and no drop outs using Vexnet 2.0. So anecdotally yes, it seems better.

However, we do not have large numbers of people running on this spectrum with the 2.0 keys yet. So do we see any interference creeping in yet? Vex says they did big device number tests.

It’s like driving on a new highway and being the only car on there versus being stuck in a traffic jam.

Or it’s kind of like being the first guy on your street to get a cable modem. It was blazingly fast until your neighbor started bit-torrenting everything using up the bandwidth the cable company doled out to your street/segment. Good at first but stinks once there’s too much traffic for the bandwidth.

The problem with situations like this is that you’re probably comparing old VexNET 1.0 keys to new VexNET 2.0 keys. To be a fair comparison you really have to compare either new keys to new keys.

There are so many variables beyond just the keys. I don’t actually remember having a dropped connection at a competition for perhaps two years. I do, however, see dropped connections frequently at school with the same WiFi keys. The keys we use are at least three years old.

I have also seen variable performance from my own personal keys. On one occasion I could duplicate dropouts on one particular key at will, put the bad key in I would get dropouts, put another key in everything was good. A few days later I tried to duplicate this with exactly the same hardware, the bad key was now working perfectly. I have no idea what was happening on the day it failed, all my parts are in essentially new condition as they never go to competitions. So it must have been something environmental that was affecting one key only I guess.

No, the VEXnet 1.0 teams at that event ran normally all day long.

I didn’t see much of those teams in the pits, but our mentor worked with some of those teams at a different tournament and he said the issue seemed to be with the new firmware.

In the next couple weeks, we are going to start testing the new keys on our “guinea pig” testbot, so we will have some first-hand experiences to share with the forums.