So, I’ve had my shiny new VEXnet Upgrade Bundle for about a dozen hours now, and so I thought I’d post a few of my initial thoughts and impressions…
The management summary is: It all works as expected, and works well.
Lots of folks seem to get caught up on the fact that 802.11 is being used, but it is best to simply ignore that for now. This is a point-to-point replacement for the crystal radio system, and you don’t have to do anything to manage it from a Wifi perspective; You don’t need a wifi network, but if you have one, no problem.
I didn’t notice any obvious latency in the system; servos and motors seemed to respond instantly to changes on the joysticks. I didn’t spend any time looking at signal strength/range or interference immunity. I was just playing around with the functionality and getting a feel for how it all works.
Installation is pretty much like it appears in the posted photos. Both the transmitter and receiver attach parasitically to the existing Vex components, so there are several connections to make. Cable lengths are just long enough to fit comfortably, but not so long as to create a cable management issue.
The plastics quality and finish looks just like the rest of the Vex system components. The exception is the 9V backup battery holder, which seems to be a softer plastic than I’ve seem them use, but I think that is necessary so you can get the battery in and out. Everything seems well made and high quality.
Once it was all hooked up, I had to pair the transmitter and receiver. This is done by plugging a special USB A<->A cable (included) into the USB ports on each unit. Paring took about 10 seconds. Now that that was done, the receiver and transmitter reliably locked onto each other in less the 10 seconds of powering on every time.
My goal for the day was to get through as many of the advertised features as possible. I tried all of the following:
*]Wireless programming (EasyC Pro)
*]Wireless On-line window (EasyC Pro)
*]Wireless PrintToScreen() logging (EasyC Pro)
Everything worked exactly like you would expect it to; no real surprises to report. It was particularly cool to get log data from a robot that was 10ft away going through its paces, and then download new software, and then watch it go again. All without bending over to pick the robot up!
At no point during any of my tests did I have a control glitch or anything that concerned me. The link seemed to be rock-solid. This testing was done in a residence with a somewhat active wifi network.
One test I was eager to try was a signal smoothness test. Basically, I just plugged a servo in to Motor port 1 and slowly (smoothly) moved the Ch1 joystick from side to side. I did this with VEXnet and then with a traditional tether cable, and compared the smoothness of the servo each time.
The VEXnet control seemed much smoother to me than the tethered connection. I don’t have any easy way to quantify my results, but it certainly looked smoother to me. This will probably be an advantage to drivers trying to use finesse in a delicate situation.
From a product design perspective, I think IFI did a great job creating these add-ons. But they are add-ons, and as such are not as streamlined as we might like. The feel of the transmitter in your hand is noticeably different, though not so much that it should be a problem. Changing a transmitter battery requires a bit more care to deal with the additional cables and connectors. Again, no real problem, but I do look forward to the more sleek VEX 2.0 hardware with VEXnet built-in.
This product lives up to my expectations, and I’m pretty picky