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Re: Sumo Bots B/C [Trial]

Posted: June 14th, 2010, 6:36 pm
by ichaelm
It is possible to use a vex transmitter and receiver, but use completely different motors and stuff. Not that I recommend it. Pretty much any Hitec or Futaba set will be cheaper than and just as functional as Vex. Or you could just harvest some brains from a cheap RC car, if cost is really an issue. As long as it has multiple channels.

About channels: The old Futaba set I have now allows you to switch the crystals on both the transmitter and the reciever. I think the more modern non-bluetooth ones come in two categories: ones where you have to switch out a whole frequency "module" on the transmitter, and ones where the transmitter has multiple settings internal to it. If you get a bluetooth one, you probably won't have to worry, because most of them do automatic open-channel-seeking.

Re: Sumo Bots B/C [Trial]

Posted: June 14th, 2010, 6:45 pm
by franklinknights
ichaelm wrote:It is possible to use a vex transmitter and receiver, but use completely different motors and stuff. Not that I recommend it. Pretty much any Hitec or Futaba set will be cheaper than and just as functional as Vex. Or you could just harvest some brains from a cheap RC car, if cost is really an issue. As long as it has multiple channels.

About channels: The old Futaba set I have now allows you to switch the crystals on both the transmitter and the reciever. I think the more modern non-bluetooth ones come in two categories: ones where you have to switch out a whole frequency "module" on the transmitter, and ones where the transmitter has multiple settings internal to it. If you get a bluetooth one, you probably won't have to worry, because most of them do automatic open-channel-seeking.

doesnt each part of robot operate on a channnel? like turning takes a channnel and driving the wheels take another channel?
then how would u change out frequencies?

Re: Sumo Bots B/C [Trial]

Posted: June 14th, 2010, 7:09 pm
by ichaelm
Ok, there are 2 definitions of the word channel, in terms of radio control. The one I was using is a specific frequency within a frequency band. For example, in the 75 MHz band, channel 70 is 75.590 MHz. The other definition is the number of signals that can be transmitted or received simultaneously. For example, you might buy a 4-channel transmitter.

Re: Sumo Bots B/C [Trial]

Posted: June 14th, 2010, 7:21 pm
by gh
Each channel of control is encoded into one signal and sent over the radio link to the receiver, where it's decoded and broken up into separate PWM signal channels which can run servos, motor controllers, etc.

The "channel" of the radio link is another term entirely. The radio spectrum is broken up into usable, regulated bands, and those bands have defined channels within them. Transmitting on different channels is supposed to allow independent communication.

FYI, there are no Bluetooth RC sets. There are radio sets that have keying, modulation, and encoding schemes proprietary to a company, which happen to operate on the same US 2.4GHz band, and can pair Tx/Rx pairs that allow them to frequency hop or adjust for interference. But they don't use any part of the Bluetooth protocol and wouldn't be close to being able to operate with another Bluetooth device.

Re: Sumo Bots B/C [Trial]

Posted: June 15th, 2010, 6:52 am
by ichaelm
Oh, ok.

Re: Sumo Bots B/C [Trial]

Posted: June 15th, 2010, 7:16 pm
by gh
Congratulations. There's a new 4 channel radio system from GWS compatible with the rules. It's 2.4GHz (meaning you don't need crystals) and is only $42 for the transmitter/receiver. Supposedly binds quickly, but I don't have specs on interference resilience.

http://www.robotmarketplace.com/products/0-GWS24TR.html

Re: Sumo Bots B/C [Trial]

Posted: June 15th, 2010, 7:40 pm
by ichaelm
Wow that is a really awesome deal. Thanks for pointing that out! The one I'm testing with right now isn't legal with the 2010 rules, but I'm waiting until the new rules come out to actually buy one. Bookmarked.

Re: Sumo Bots B/C [Trial]

Posted: June 15th, 2010, 8:11 pm
by JBoyd-NY
Congratulations. There's a new 4 channel radio system from GWS compatible with the rules. It's 2.4GHz (meaning you don't need crystals) and is only $42 for the transmitter/receiver. Supposedly binds quickly, but I don't have specs on interference resilience.
The instructions for this transmitter indicate that the transmitter and receiver are bound to each other - the receiver will only react to instructions from the transmitter and will ignore any other radio transmissions, even if they are on the same frequency. This is as bullet-proof as you can get with a remote controlled robot.

Re: Sumo Bots B/C [Trial]

Posted: June 19th, 2010, 6:55 pm
by lllazar
gh wrote:Well, you're also pointing out the cost of the event while commenting on the discontinuation of a Vex product. There's more than one axis of ironic beauty to that statement.
Well saying it's expensive doesn't necessarily mean we aren't willing to raise money for it...

Re: Sumo Bots B/C [Trial]

Posted: June 24th, 2010, 5:41 pm
by M-E-T-H-O-D MAN
Sumo bots looks dope but we don't have it at our states.