Sumo Bots C

[maggymay]

As GH reported back in June, Robot Marketplace has a 2.4 GHz transmitter/Receiver that they are selling for $42 for the pair ($32 for the transmitter, $10 for the receiver). Look at http://www.robotmarketplace.com/products/0-GWS24TR.html

My partner and I got one of those, and we can testify that they work just fine. The only problem is that one of the channels will default to full-speed ahead if you shut off the transmitter before the bot. So, just remember to shut off the bot first.

So, no programmable actions at all, remote control only. Where are people finding parts and stuff? Are any of the commercially-available kits of any use at all? My team has no robotics team or used parts to fall back on, this event could be a really big mess for us this year ...

If you're looking to start really really simple, I suppose you could get an RC car from radio shack and modify it. Try to find one with differential steering (the wheels don't steer like a real car). Then you could start experimenting with different wheels, or different motors, or higher voltages. I mean, in my opinion, a custom built bot would be a whole lot better than a modded RC car, but it's a start.

Ok, looking at this transmitter/receiver mentioned upthread, the reviewers at the robot marketplace say that it does not fail-safe on 3 of the 4 channels...is that a possible issue during competition? Does it just mean you have to turn the darn thing off so the motor doesn't burn out or something? (I do envy everyone here who actually knows what they're doing ...)

[ichaelm]

It means that if you turn off the transmitter before the robot, it will go crazy. So you don't do that.

[JBoyd-NY]

The instructions that come with the transmitter/receiver state: "Fail-safe: In case of loss of signal or transmitter power off, the throttle channel will go to the idle position (1.0ms). The other channels will hold last position."

Fail-safe is the procedure followed by the receiver when it is no longer receiving instructions. This can occur because something is blocking the radio waves (when this transmitter is used for aircraft, they warn the user to keep the aircraft in sight, as large buildings may block the transmissions from reaching the receiver). It can also occur if the battery powering the receiver starts to lose power (systems get shut down to avoid damaging the robot, hence the term fail-safe). In the Sumo Bot event there will be no large objects between you and the bot, so there should be no problems with a loss of signal. So long as you follow the directions and turn the receiver and transmitter on and off as instructed, the fail-safe should never be a problem.

[maggymay]

Thanks everyone for your tips/advice, muchly appreciated - if we do end up getting the robotmarketplace transmitter/receivers I'll try to remember ..."Read. the. directions."
Hey, I've come across these Elenco Snap-Rovers online today. Has anyone tried to use them as a SumoBot base? (We are so out of our depth in this event...)

[Littleboy]

Does this event allow the use of programable robots?

[ichaelm]

MalvinO wrote:
I have a few questions about the rules:

1. Can parts of the robot be autonomous? For instance, can an action be triggered by a sensor or button on the robot? Can a pre-programmed action be initiated by a controller?

2. How many remotes and channels can we use at once? Can more than one person control parts of the the robot at a time?

1. The rules specifically state that the bot must be controlled by radio remote. Autonomous action by the bot would violate this rule, as the bot is not being controlled by a radio remote. A pre-programmed action that is triggered by the remote control would fit into this rule.

2. If more than one remote is used, then each needs to be able to operate on different frequencies. The purpose of this rule was to make sure that any two bots can compete against each other without radio interference. If you use two remotes and one can only operate on a set frequency, then it isn't possible to insure that matches can be set up with all possible opponents without two bots trying to use the same frequency at the same time. So long as both transmitter/receiver pairs have changeable frequencies, four sets of crystals would meet the rules requirements and insure that bots can compete without any interference (provided that both controllers operate on the same major frequency so that the extra crystals can be used in either transmitter/receiver pair.) If the two transmitters operate on different major frequencies (say 75 MHz for one and 27 MHz for the other) then you would need three pairs of crystals for each transmitter/receiver pair.

[harryk]

Warning to all: make sure the proctor understands the rules well
As a result of bad proctoring I was eliminated before the final block when obviously I had the best bot

[quizbowl]

Thats horrible? What happened?

[ichaelm]

Warning to all: make sure the proctor understands the rules well
As a result of bad proctoring I was eliminated before the final block when obviously I had the best bot

You did? That's a pretty big assumption. Aren't you the same guy who said you were using 6 AA batteries?
But still, sorry man. Was this at an invitational?

[harryk]

Warning to all: make sure the proctor understands the rules well
As a result of bad proctoring I was eliminated before the final block when obviously I had the best bot

You did? That's a pretty big assumption. Aren't you the same guy who said you were using 6 AA batteries?
But still, sorry man. Was this at an invitational?

I have new nimh batteries now, but anyway what happened was a the team who won my block should have been disqualified for a few things:
- they were called about 5 times but they were broken down every time(you get 90sec once you've been called otherwise you forfeit the match), then they jumped in for the last 3 rounds while I had just one 8 or so fights in a row
- they repaired there robot using parts from their B team's robot(you can only use supplies YOU impounded)
- then when I faced them there robot climbed on top on mine before braking again, so I proceeded to carry them out of the ring, now based on the positioning the other robot exited the ring before I did and I should have won, but the proctor declared it a draw and proceeded to lightest weight which is why they won. I requested a rematch and the other team even agreed but the proctor said no

So yeah there you go, and yeah this was an invitational so it doesn't really matter but it still makes me angry when people don't know the rules