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Brandon_L
11-05-2010, 10:40 PM
I'm working with the Barat Foundation based out of Newark, NJ. They go to different inner-city schools and such and work with students (I'm pretty sure its middle school) to create giant 3 dimensional pieces of art that they call "Animodules". Basically, a bunch of giant 2D shapes put together to create 3D, colorful animals that the kids paint.

They wanted to make one robotic, that could talk and drive around and what not. It would be about 5 feet tall, I have no idea about weight yet as I haven't got to see the material myself yet. I looked into this (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0510)but its a bit over budget. Are there any other types of control systems? Does the vex system have enough power to move a robot that could possibly be 20-50 pounds?

Help!

Hawiian Cadder
11-05-2010, 10:49 PM
if you want to get into some more advanced ish robotics, i would recomend an arduino, some light mosfet controllers, and these for motors-

http://www.robotcombat.com/products/0-FT-SPARK16-86.html

there are multiple gear ratios and i have worked with them in the past, the are alright for light stuff.

Chris is me
11-05-2010, 10:49 PM
If you want to go FIRST-like and can donate stuff like Victors you can run a Vex microcontroller ($50 on ebay) with a PDB and Victors for the drive. Buying a CRIO for such a simple robot is overkill.

rahilm
11-05-2010, 10:51 PM
You could try using CIMs ($20ea.), Victors ($100ea.), and an Arduino for control ($30), and the wireless components like Xbee, etc. (~$150 for all)

For a 4 CIM drivetrain, it would run about $660, leaving $340 for all the material.

Brandon_L
11-05-2010, 10:52 PM
If you want to go FIRST-like and can donate stuff like Victors you can run a Vex microcontroller ($50 on ebay) with a PDB and Victors for the drive. Buying a CRIO for such a simple robot is overkill.

That sounds good. How much are jags/victors by themselves? (although I might be able to borrow our teams victors. Isn't there a rule or something saying you cant use them (in FIRST)?)

rahilm
11-05-2010, 10:56 PM
Isn't there a rule or something saying you cant use them (in FIRST)?)

Victor 884s are still allowed. Any other Victors are no longer allowed.

Brandon_L
11-06-2010, 09:38 AM
You could try using CIMs ($20ea.), Victors ($100ea.), and an Arduino for control ($30), and the wireless components like Xbee, etc. (~$150 for all)

For a 4 CIM drivetrain, it would run about $660, leaving $340 for all the material.

I searched the IFI website for victors and couldn't find anything.. do they have a separate shop website or something? But I also like this idea, although Ive never heard of Arduino and Xbee has been a pain in the butt to me in the past...

http://arduino.cc/en/uploads/Main/arduino_uno_test.jpg

And I don't see any obvious PWM input/outputs but it could just be me.

StevenB
11-06-2010, 10:34 AM
IFI sells Victors under the VexPro name (http://www.vexrobotics.com/products/vexpro/victor-speed-controller.html).

Before you start trying to chase down a specific controller, take a step back and figure out what you need.
Figure out what size and weight you're dealing with, and use that information to select your motors. Given the size of your motors, figure out what current your motor drivers (speed controllers) need to be able to output. From there, you can select a motor driver. My gut feeling is that a Victor is way overkill, so I encourage you to look around at all of your options.

The Arduino is a great controller because of its ease of use and relatively low cost. It doesn't have "PWM ports" like we're used to in FIRST (where there's a set of 3-pin headers with power, ground, and signal), but it definitely does have PWM output. Look closely at the picture and you'll see them in the top-right corner of the board. You'll have to manually connect power and ground, or buy a board like this (http://www.robotshop.com/dfrobot-i-o-expansion-board-4.html).

thefro526
11-06-2010, 04:22 PM
Brandon,

I'd second the vex controller suggestion just because of how available they are and they're pretty inexpensive and easy to program.

For motor controllers I'd check with some local FRC teams and see if they have any older Victors or something that they'd be willing to give up. Shoot, I'm pretty sure I have one or two Victor 883s I'd be willing to give up to a good cause if I can find them.

dtengineering
11-06-2010, 04:35 PM
You should be able to get a used laptop (for free) with a serial port on it.

The new Jags (are they still $80 with an FRC discount?) will accept a serial input, and have inputs for pots and encoders built in to them.

For something smaller, check out ROBOT or SERVO for servo controller boards that provide similar function, but for multiple servo motors.

All the laptop needs to do is send serial signals to the Jags (or servo board) saying "go to this position" or "rotate at this speed".

You might want to check out http://www.robotsee.com/ for some interesting options... like using an old Android phone as your controller, or tying in a webcam or joystick to that old donated laptop.

For the ultimate in "cheap" though, you can run two 1 amp brushed motors off an L293D H-bridge chip (a buck or two, it's "big sibling" 2A version the 298 is just a bit more) and control it all with an Arduino or PIC.

Jason

jamie_1930
11-06-2010, 08:34 PM
If you want to go FIRST-like and can donate stuff like Victors you can run a Vex microcontroller ($50 on ebay) with a PDB and Victors for the drive. Buying a CRIO for such a simple robot is overkill.

Instead of using a Vex Controller, which buying would be cheaper, I would suggest using one of the IFI controllers. This is for two reason any local FIRST team near you probably has a dozen and wouldn't mind giving one up for no cost, plus if you do make this first connection with a FIRST team you will probably find them willing to help mentor some of your students on how to build what you want.

Also you could buy just the chassis that you saw here (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0205) and then add some toughboxes, motors, and wheels for less than around $300

Chris is me
11-06-2010, 08:49 PM
The Vex controller is just generally really useful to have and the controller is nice / better anyway. So great for quick prototypes!

Anyway here's how I'd do it assuming the cost for attaching the superstructure is negligible:
1 Vex v.5 controller and transmitter combo ($50-$100 on eBay)
1 IFI Kitbot ($190) and some AM Toughbox Nanos ($160 total) with CIMs ($60 total) (you can use the AM kitbot too, I just figure the adjustable wheel positioning might be better)
1 FIRST PDB ($190)
1 120 amp breaker ($30)
Various wire, a pegboard for electronics, other stuff ($50)

total <$800

Vikesrock
11-06-2010, 09:37 PM
The Vex controller is just generally really useful to have and the controller is nice / better anyway. So great for quick prototypes!

Anyway here's how I'd do it assuming the cost for attaching the superstructure is negligible:
1 Vex v.5 controller and transmitter combo ($50-$100 on eBay)
1 IFI Kitbot ($190) and some AM Toughbox Nanos ($160 total) with CIMs ($60 total) (you can use the AM kitbot too, I just figure the adjustable wheel positioning might be better)
1 FIRST PDB ($190)
1 120 amp breaker ($30)
Various wire, a pegboard for electronics, other stuff ($50)

total <$800

This is missing motor controllers and a battery. If you want to stick to familiar FIRST components a pair of Victors for $200 and 12V SLA battery for ~$40 (FRC battery is 18AH for a battery life reference) should do the trick.

The FIRST PDB would be serious overkill for the setup above, I would drop it and replace it with a simple fuse block like FRC used to use like this one:
http://www.halfpricecaraudio.com/Stinger-SPD8625-MAXI-Fused-Distribution-Block-2-4-Gauge-Input-4-8-Gauge-Outputs-Gold.htm

Then use the same 40A Auto-reseting breakers you would for the PDB and get an inline ATC fuse holder for a 10A to fuse the Vex controller. Should be about $55 or so instead of $190.

Brandon_L
11-06-2010, 11:30 PM
Wow guys, thanks for all the suggestions and replies. Really didn't expect this. I could probably get one victor from my team. I'm guessing two motors would be enough so that leaves one more to get. If anyones team is willing that would be wonderful! (or any other parts at that)

The IFI controllers is also a good idea. I know I have our old 2008 (our rookie year) control board locked up in a cabinet. Only problem is that it was set on fire (err...my bad) and I'm not sure if it works anymore. Ill attempt to resurrect it. If not, I guess VEX would be the way to go.



The FIRST PDB would be serious overkill for the setup above, I would drop it and replace it with a simple fuse block like FRC used to use like this one:
http://www.halfpricecaraudio.com/Stinger-SPD8625-MAXI-Fused-Distribution-Block-2-4-Gauge-Input-4-8-Gauge-Outputs-Gold.htm


I know for a fact we have one of those from our 2008 board, assuming its not burnt to a crisp.

Thank you so much guys. I'll keep you posted on how it goes (we meet every Saturday @ NJIT)

P.S.
I am living proof of why teams should never let there programmers wire : P

AdamHeard
11-07-2010, 12:10 AM
The Vex controller is just generally really useful to have and the controller is nice / better anyway. So great for quick prototypes!

Anyway here's how I'd do it assuming the cost for attaching the superstructure is negligible:
1 Vex v.5 controller and transmitter combo ($50-$100 on eBay)
1 IFI Kitbot ($190) and some AM Toughbox Nanos ($160 total) with CIMs ($60 total) (you can use the AM kitbot too, I just figure the adjustable wheel positioning might be better)
1 FIRST PDB ($190)
1 120 amp breaker ($30)
Various wire, a pegboard for electronics, other stuff ($50)

total <$800

I'd say do this, but not use a PDB, there are cheaper breaker panels.

Definitely use a vex controller, for sure.

You could probably knock half this cost down by begging and stealing some kop frame, wheels, and gearboxes. We certainly have a heck of a lot of rover wheels if you want.