Making the VEX microcontroller smaller

VEX V5 General Discussion Technical Discussion
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I am competing in the ASME Student Design Competition and using the VEX system to build my device. However, the radio controller that comes standard with the system is way too big to fit within the size limitations the contest rules allow. Has anyoen had any success making the device smaller? Are there any alternatives to the controller? Save taking the thing apart and trying to rearrange them and custom build a housing for them that will fit I have been unsuccesful in finding a workable solution.

I appreciate any thoughts or insights.

-Mike Lowry

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Does anyone have any actual weight specifications on the aluminum parts? I am trying to see if it is worth the investment to swap out the steel and save some weight (which counts against me in this competition I am entering into).

3

I started a spreadsheet of the weights of various Vex parts, although I never finished it. Here is what I weighed before I lost focus and went on to the next project:

Part Wt/Grams Wt/Oz
Gear, 12 Tooth 2 0.07
Gear, 36 Tooth 6 0.21
Gear, 60 Tooth 12 0.42
Gear, 84 Tooth 40 1.41
Wheel, 4" 85 3
Wheel, 2.75" Normal 55 1.94
Wheel, 2.75" Omni 40 1.41
Wheel, 2.75" Vexplorer 50 1.76
Wheel, 4" Omni 100 3.53
Track, one foot 50 1.76
Track, drive sprocket 20 0.71
Track, large bogie 35 1.23
Track, small bogie 25 0.88
AL, angle, 3x3, 12.5" 50 1.76
AL, C, 3x1, 12.5" 50 1.76
AL, wide, 5x1, 12.5" 95 3.35
AL, Chas end, 3x1, 12.5" 45 1.59
AL, 1xstrap, 12.5" 12 0.42
AL, flat 5x0, 12.5" 60 2.12
Controller 125 4.41
EL: Motor, drive 45 1.59
EL: Motor, servo 45 1.59
EL: Encoder 35 1.23
EL: Rheostat 15 0.53
EL: Ultrasonic RF 30 1.06
EL: Limit switch 20 0.71
EL: Bump switch 20 0.71
EL: Line detector sensor 15 0.53
Chain, per foot 4 0.14
Chain, 48T sprocket 12 0.42
Chain, 40T sprocket 10 0.35
Chain, 24T sprocket 6 0.21
Chain, 15T sprocket 4 0.14
Chain, 10T sprocket 3 0.11
Beam, 3" 8 0.28
Beam, 2" 5 0.18
Beam, 1" 2 0.07
Beam, 1.5" 3 0.11
Axle shaft, per inch 2 0.07

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Is it possible for you to measure the weights of two identical pieces of aluminum and steel for weight comparison purposes such as one piece of aluminum c-channel and one piece of steel?

5

If you just want remote control, they have that little doodad that only gives RC control of motors.

6

Thanks for the list of the weights, it will prove helpful in my analysis. I would weigh the parts but my goal was to determine if the savings in weight was worth the cost of the entire AL metal kit.

As for the doodad with the radio control of the motors, the signal splitter is one thing I am considering. It is like a third the size and half the weight of the microcontroller unit.

I realize that in my sheer noobiness, I have mis-titled this thread. the device that is too large is the VEX Transmitter. XD.

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There is no alternative for the vex transmitter. The only thing i can think of is to buy a vexplorer control system because that one is smaller.
note that you will also have to buy vexplorer motors.

8

If you have no need to program your robot, then the Vex signal splitter can do the job for you. otherwise, you can’t really make it smaller. if you’re in no hurry, Vex mini is coming out later on, and it will be significantly smaller. Since this is a term project though, you probably don’t wait to wait it out. If the signal splitter won’t do you, you’ll have to look for another microcontroller.

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I’ve taken apart the transmitter and the board inside is about as 2-D big as the case. You might be able to hack up the back of the case to make it thinner but you’re practically stuck with the transmitter.

10

Thanks for your insights. I’ve decided to take apart the transmitter and attempt to nestle the components into my size requirements without damaging or ruining the controller. If I succeed in this endeavor, I will post my results and pictures for those who wind up in my challenging position.

Thus far: I have successfully taken it apart and put it back together and it still works. I took some dimensions and will be using a Lexcan board to screw or Velcro (or duct tape? hehe) all the components to. More status updates by the end of the week.

-M

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Please post on your final product for this project you are doing when you finish. I want to see whatever it is that you are building with this kind of size restriction.

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Update:

I have successfully (and painstakingly) succeeded to take apart the vext transmitter and make it smaller. With a screwdriver, a soldering iron, some cardboard in between boards to prevent random connections being made accidentally, some extra wire I ripped off some old computer fans, a whole lot of patience and a whole lot of electrical tape, I have made it fit within the odd shaped space in front of my robot’s gripper arm.

However, there will need to be some ‘refinements’ i have to make with regards to the button controls. It still works, though I think I somehow fried the RX port #1 on my microcontroller and needed to reprogram for RF port #2. I also need to double check the rules about )a the telescoping antenna (can I telescope it myself after the competition starts, or does it need to fit inside in the start config and I can’t touch it?) and b) do I have to neccecarily use rechargable batteries to operate the vehicle and the transmitter?

The only thing is that now it kinda looks like a crude IED…I gotta potentially make it look a little less like something you’d get arrested at an airport for and a little more like the helm of a killer robot.

More updates and pictures to come later

13

Everyone,

Thanks for your interest in my project. I have met success and uploaded some pictures on Facebook with some descriptions and close ups. The captiosn explain what you are seeing and how it all works. Please feel free to drop me some comments.

Robot Pics

I still have some things to hash out. I am going to re-enforce the controller with a VEX angle brace along the long part of the ‘L’ shape. The control still has a new feeling to it compared to the normal transmitter. It’s much closer together. The foam (not pictured) between the battery pack and the control joysticks allows for motion forward and backward. The button on the left moved the arm up and down and the one on the right opens and closes the gripper. The driving is tank style differential drive.

Current plans (minor changes): Custom battery pack to deliver 9 volts to add extra power to the motors. Also, the antenna needs some gluing or securing so that it doesn’t risk falling out and dragging after coming out of the box.

More updates later,

-Mike

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I need a Facebook account and am not planning to get one. Any other way?

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Update: I finally found the SD card with the pics of my final competition design. Including step by step dissasembly of the vex transmitter.

on Facebook, they are located here: http://www.facebook.com/profile.php?id=194901535&ref=profile#/album.php?aid=2032806&id=194901535&ref=mf

For those without Facebook, I am uploading the pics from this recent batch to a flickr account. www.flickr.com/thenapkinengineer

I will update the first set of pics there, but I think I have to wait till next month to not go over the photo limit of 100MB. (That’s a bit of a pain, and I appologize for the inconvenience.)

I will also see if I can fit all these pics on my NJIT webspace (but I have to build that website first, so it may take some time). Find a friend with Facebook to let you see the pics if you can in the mean time.

Jimmy, I will let you know when I get the pics on a public domain.

-M-

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