The ones that run on 2.4ghz are pretty much, from a rules standpoint, operating like bluetooth to my knowledge.
At the national tournament, we have 60 teams to judge in 6 hours, less breaks & lunch and then have to turn in the scores to avoid delaying the awards ceremony. A large goal when I and others write rules (besides a good learning challenge for the students) is how to supervise the event accurately and efficiently. A key part of that is to avoid specialty measurement devices whenever possible (unless maybe I'm looking for an excuse to buy something, and even then I try to make sure there are low tech answers). The tools to measure broadcast frequency are just not something most people will have. And while voltmeters are more common, access to all test points is problematic at best. As a result, the rules are written to depend on MANUFACTURE'S LABELLED specifications for things like voltage (batteries are generally less than label voltage) or broadcast frequency.
So, instead of challenging the event supervisor with 'knowing' your xbee TRANSMITTER is operating on 2.4 GHz, or expecting them to look up specs on the internet, just make sure the device is clearly labeled by the manufacturer, you know where it is, and you can easily point it out to the event supervisor when asked! Again, its the TRANSMITTER that has to be checked under the rules.
Oh, and frequency hopping is OK, as long as its within the allowed bands.
My suggestion would be to change the rules slightly to permit a student to provide documentation from the vendor or manufacturer that states the frequency.
So regarding frequency hopping, would a robot that uses that technology be considered able to operate on at least 3 frequencies and therefore no changes would ever need to be made to it in that respect in order to compete legally? Cuz then that seems like a no-brainer to me.
I know some Xbee's allow you to set a channel mask or something along those lines which allows you to set which channels in the 2.4Ghz band it uses, but for other events, like Sumo Bots, for example, it may be impossible to remove the module, connect it to a laptop, and reprogram it all within the few minutes setup period.
Also, what advice would you have as far as the reliability of using Bluetooth or other 2.4GHz systems (they are different, right? bluetooth implies frequency hopping while you can also just have a standard 2.4GHz transmitter?) concerning problems with cell phones, wifi, etc. that I've heard about?
Personally, I'd submit a clarification asking wether or not a spec sheet from the manurfacturer stating that a device uses the 2.4GHz band is acceptable, if yes, use XBee, if no, use Bluetooth. To me wifi is way more trouble than it's worth. Of course, if I were in this position Id stop trying to go wireless and get a USB cable in there so I could get it done and practice in time
Yeah, I'm not using wireless for Robot Arm for this year- I was more thinking about future years, and it was a question on my mind that I was just wondering about for general knowledge purposes.
iwonder wrote: But I can't imagine any scioly event like robot arm that would have 200 bluetooth devices in the crowd.
Really? Oftentimes at the larger tournaments you'll have hundreds of people in a gym observing various events, including robot arm. I'd think you could easily encounter the same issue you mentioned.
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National Physical Sciences Rules Committee Chair
So what advice would you have as far as a reliable way to implement wireless communication and still be able to use a controller more like a video game controller than an RC airplane controller?
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I think the justification for that might be that when the ball is placed in the telescoping arm, the arm scores a point for holding the ping pong ball in (above) the north zone. Then it is raised. However I still don't think it'd count because: 1. The lifting action wasn't a separate, distinct, and final action in the run (they scored another ping pong ball when lifting and placed the ball in the north zone) and 2. The lifting action didn't start at the ground elevation. Those two things were explicitly clarified in the last two FAQ's here: http://www.soinc.org/node/473ohiostar wrote:http://m.youtube.com/#/watch?v=0c9Lu2DwO-I
Has anyone seen this in person? It's hard to tell, did the part of the arm that raised the ball previously score at least one point? Impressive!
Nonetheless, that looks like an incredible arm, must've been expensive though
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