After having competed in the BEST competition this year with my school and doing quite well for a first year team, I have been collecting parts to build a robot of my very own. It is a robot that is going to be about the size/complexity (slightly more complex) than a BEST robot. I have rounded up all of the parts I need EXCEPT a good dev board. The BEST BRAIN (Their dev board) was nice in that it had multiple digital I/Os, servo outputs (not neccesary), as well as 4 motor outputs. I was wondering if any of the geniuses over here on the FIRST forums would know of any dev board that combines motor outputs (would you call that a speed controller?) and Digital I/Os. I was looking for an all in one solution just for the simplicity and convenience of it. If you guys think I should move up to big boy parts, a nudge in that direction would be appreciated as well.
The arduino is a pretty cheap I/O board. It has digital I/O and analoge I/O so it can output a PWM signal. You would need a seperate motor controller.
Already have a Duemillanove, love it.
I was just wondering if there is a magical product (like the BEST BRAIN) that combines that motor controller. Ive seen a motor shield addon for the arduino that is a bit small. Im looking to be able to drive 4 motors as well as 4 servos, while still retaining IOs for sensors/diagnostic lights
You could try out the VEX brain. It’s not cheap but it’s reasonably durable and has built in PWM output.
How much oomph do you need for the motor outputs? I’ve seen a couple motor control arduino shields that might work.
The adafruit shield doesnt have as many servo outs as I would like. As far as my larger motors go, they are continuous rotation, not PWM. Doesnt the VEX brain only have pwm outs?
P.S.- When I say cheap, I mean not a CRio lol. $150 is not a big deal
Ok so one guy on my team once met this guy who invented something that is EXACTLY what you are looking for, at least i think so. The product is called a roboduino and essentially its compatible with arduino software and has 6 PWM out pins 6 ANalog pins and 14 digital pins, it is great for beginners and experienced people and i believe the fully assemlbed product costs about 50 bucks, so yeah i hope this helps
oops forgot the link
hope this helps
That’s the closest thing ive seen yet, pretty nice little product, although it looks like much of the functionality is the same as the stock Duemillanove. Is it possible to drive motors with that thing(non PWM)?
Sparkfun has some cheap motor controllers that you could use to power a motor off a vex controller. You could also take a continous rotation vex motor, open it up, and pull the electronics out; they will function as a small speed controller.
If you’re planning on using something with more current, you’re going to need to go with a larger speed controller.
I’m still inAuburn for Souths best. I find it funny that they are lke ROBOTICS! but yet, they aren’t. our teamsmotor mounts failed, so we weren’t as satisfied as we hopedbut still got about 25th overall.
Well John, being a BEST expert, do you know if it is possible to purchase a BEST BRAIN? As for using the servos speed controller, my motors are quite a bit larger than the Vex ones, and draw more current
if you have a ardunio Duemillanove board that already has pwm outputs why not just get RC speed controls that take a pwm input to control a larger motor. In FIRST we use the innovation FIRST victor or the Texas instruments Jaguar, but realistically there are tons of other options. http://www.robotmarketplace.com/products/speed_controllers_main.html
Integrated speed controllers is not a common thing for cheap development boards but if you already have pwm you might as well use that for control with a secondary controller.
You might want to take a look at this web site. Allot of AVR and motor drive and controller solutions. http://www.pololu.com/. Wireless PS2 controllers are not to difficult to interface and use as a wireless robot controller. One of my favorite combination motor and servo is the Dynamixel AX12+. They are controlled by a serial bus kind of like what we will be doing with the can jags. http://www.crustcrawler.com/motors/AX12/index.php?prod=63 And the VEX brain really isn’t that bad when you consider that it is part of a system. You can do allot more with it than build vex robots. I had a great time VEXING my neighbor’s kids large gas powered truck.
I think this is exactly what I want, in the smaller, more convenient form factor that I was yearning for.
Post any concerns that you may have. Are there any obvious problems with this board?
If you are only looking for on/off control of your motors then the board you linked will certainly meet your needs. To get variable speed control of your motors using that board without a speed controller, you would have to use the high current digital output as a PWM style output. Depending on the speed of the controller and what other software you running this may or may not work. Someone else may be able to shed more light on the feasibility of this.
If you are planning on using a speed controller this board only has 4 dedicated PWM ports and you would need 8 for both 4 servos and 4 motors. Your Arduino would be closer to meeting your specs with 6 PWMs.
If you’re fine with relay style control, I’m not familiar with BEST, so the size comparison doesn’t help me much. It looks like the high current outputs on the board are limited to 1A, will that be enough for your motors?
Im not really sure what I was thinking when I posted that…
I decided on two of these, http://www.robotshop.us/dimension-engineering-sabertooth-2x10-1.html, which I will use in combination with my Arduino. I own a radio with mixing, and because the majority of my autonomous functionality will come at a later date, I will hook my drive motors right up to my receiver. Thanks for all of your help gents, and I have one last question: What do you think the best board is above an arduino? Ignoring my previous request for integrated speed controllers lol
You could take a look at the Microchip PIC line of microcontrollers as an alternative to Arduinos. They are dirt cheap; if you have a university e-mail address, you can actually get the microcontrollers as free samples.
I don’t have very much experience with microcontrollers, but you can see a simple board I made here: