2010 Kit feedback for 2011 Kit

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KIPR Matthew
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Fair enough. What parts could you guys not live without? Or maybe a better way to phrase it is, what part would cause the most uproar if removed from the kit?

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KIPR Matthew
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How do you currently like the motor counts? Is it good having all of the same type of motor, or would you prefer a variety?

How are the sensor and motor wire lengths? If we made the sensor wires longer would that be helpful? Speaking of sensors, are there any sensors you would like to used that currently are not?

Lastly, did anyone use the slot sensors that were new this year? There was a large demand for them last year, but I have maybe seen one or two used so far.

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Jeremy Rand
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PiPeep: FYI, a GCER paper is in the works on fun things with the ET sensor; one of the things covered includes converting the funky analog10() scale into a linear value.

KIPR Matthew:

I would like to see more motors. I really liked having 9 motors in 2007, as it allowed people to innovate about how to use the 9th motor (as Norman North and La Jolla High did). I like the black motors much better than the white motors that we had in previous years; if white motors are reintroduced, I would prefer them to be in addition to the 6 black motors we have rather than replacing them. The IFI motors we had last year would be really nice to have again, BUT only if current limiting is added to the CBCv3's motor controller (which I understand was debated and decided against for the CBCv2).

Longer sensor/motor wires would be really nice, but one innovative use for the extension cables is to change the pinout of ports, and we feel really restricted by the 2 extension cables that we have (trying to have a large bot and also do pinout tweaks doesn't work when you have 2 extensions). If you can't give us 4 extension cables, maybe you could cut the length of the cables in half and give us 4 of them? That way we get the same length of extension but we can be a bit more frugal with them.

Regarding sensors... we didn't use the slot sensor or the sonar, but if you keep the sonar, perhaps you could revert to the SRF04 sonar? The Maxbotics sonar that replaced the SRF04 in the 2009 kit is very inferior. Far less accurate, and useless below about 10-15cm. I realize that the CBOB firmware would need a change to be aware of how to work with a timed sonar such as the SRF04, but looking at how simple it was for Kyle to add that to the XRC in 2005 makes me think that it can't be too hard to add it to the CBOB.

Hope this feedback helps.

-Jeremy Rand
Senior Programmer, Team SNARC (2012-2013), Norman Advanced (2010-2011), Norman HS (2008-2009), Norman North (2005-2007), Whittier MS (2003-2004)
2012-2013 VP of Tech, 2011 President, Botball YAC (2009-2013)
Mentor, Alcott and Whittier MS

AdamF
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I agree with Jeremy's suggestion to give us the same length of extensions, but maybe in more pieces. Longer wires all around would also be nice. Especially when the game basically requires you to expand beyond the 15in height limit to get Botguy, it would be great to not have to finagle so much to get sensors at the right heights for sensing both pvc and stuff on the island.

Our team was discussing today how awesome it would be to have about 8 ET sensors because we could entirely map the board with some creative algorithms. We currently don't use the sonar... I'm not sure why though.

As to motors, I think that 6 motors is enough, and I think the black motors are good enough quality for everything I have seen them used for. I guess more couldn't hurt, but then you start to run out of pieces to build effectors with...

I could definitely live without the iGus slider thing. I feel like you probably get good sponsorship money for including it though so... The problem is it doesn't match up with any holes (LEGO or metal) and we would have to use up our 36in of tensile element allowance to actuate it.

Adam Farabaugh
Hampton High School

PiPeep
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Jeremy: I look forward to seeing that paper. :-D

devitrify
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Gyro/Yaw rate sensor, with function calls that returns the heading of the robot.

The Gyro/Yaw rate sensor probably would require software/electronics that handles the drift after integrating the gyro sensors output, since (I believe) the software at the user level is too slow for accurate integration and drift elimination.

I think most Botball'ers would find knowing the robot's heading very valuable. The heading info is far more valuable than the info supplied by the provided 3-axis accelerometer, which to date, we've only found useful for navigating "up hill" (Botball 2009). Bearing data supplied by a gyro/yaw rate sensor would allow closed loop steering as robots navigate the board, with immunity to wheel slippage.

KIPR Matthew
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Gyro/Yaw sensors still only measure acceleration, just a different kind. Currently you can check your BEMF readings against the accelerometer to see if you are accelerating when you should be. You could also do the time derivative to get your current velocity reading.

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devitrify
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A Gyro / Yaw sensor with well designed support software can provide Botball'ers a simple means of knowing their heading. Solutions measuring BEMF and linear accelerometers aren't as simple.

Gyro / Yaw rate sensors such as Analog devices ADXR610 family provide angular velocity as output. When integrated properly and compensated for drift, you can obtain a reasonably stable heading angle for the duration of the Botball match.

Current sensors in the Botball'ers toolbox don't provide an easy means of determining heading. The easiest way is by frequently 'squaring up' against the Botball arena's PVC borders after every turn, like a blind man instead of a high tech robot. The proposed method of comparing d BEMF / dt to the acceleration, when one is going straight, may indicate slippage, but it does not provide corrected heading information. Nor does the 3D linear accelerometer on the CBC provide any output when turning about the sensor itself.

Once a Botball robot gets off its heading after its wheels slip, few Botballer's have the means to correct with the currently provided sensors. A well implemented gyro/yaw rate sensor, integrated into the CBC, would be a powerful navigation sensor in the Botball'ers toolbox and a welcome addition to the kit of parts.

abdullahalshackarchi
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I agree with the gyro sensors, one of our biggest programming challenges was keeping track of the heading.

In our opinion, while the pieces are useful and of wide variety, we simply need more Lego. This year's board is even bigger, and we need bigger robots. We are almost out of Lego and to compensate, we had to build one of our robots completely out of metal.

Thanks,
Abdullah

Adam
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the number of motors are good.

I think it would be nice if there was more than just one hub cap lego piece. (the ones that are round on one side but flat on the other.