Rev Robotics Expansion Hub

Technical Electrical
1

Hey yall,

Have any other FTC teams tested out the Rev Robotics Expansion Hub, and if so, have any of you guys noticed a lag in the hub’s operation? For example, when you use the game controller and tell the robot to stop it takes an extra second for the robot to stop moving. Wondering if this will serve as a hindrance to maneuvering during the games…

Thanks for your input! :]

2

I haven’t experimented with the hub yet, but I have seen this occur periodically with Modern Robotics controllers in the past. I haven’t been able to isolate it, but it may be the same issue related to the software, not necessarily the hardware. I’m hesitant to say that’s definitely the case though, as I never figured out what it was with MR equipment.

3

We supported a FIRST Global team this summer and they were having that issues with it. We think it had do to with wifi interference because when we had them take it away from their school wifi it worked fine. We’ve not had any problems when we’ve tested it this summer, but we’ve not done that much, yet.

We had the same issue with the MR controllers during one of our matches in Houston, and sometimes during practice at our school, but we never saw it anyplace else last season and we played about 60 matches at a bunch of venues.

4

Thanks for all the input! Also, it appears that when connecting the two expansion hubs to the RC phone requires an intermediate USB hub. Has anybody been able bypass this USB hub in connecting two Rev Robotics expansion hubs to the phone?

5

To connect two ExH’s to a phone, you plug one ExH into the phone with the OTG cable directly, and then chain the hubs together using the provided 3-pin JST (RS 485) cable and XT30 power cable. No need for a USB hub at all.

Here’s some more detailed directions on how to configure the ExH’s for use when chained: https://www.reddit.com/r/FTC/comments/6twjaj/how_to_connect_two_rev_expansion_hubs_together/