Marry RC cars and autonomous control

[kenjones1935]

I am trying to install microcontrol into a 1/10 scale radio control hobby level car. My idea is to blend the speed and accurate miniaturization of radio control cars with the formal language and repeatability of autonomous control.

Has anyone done this with a VEX?

Has anyone done this with a proto board?

Has anyone done successfully at all?

Ken

[kenjones1935]

Why would I want to do this?

Our schools are focusing on STEM. Some of the kids need to be 'hooked'.

RC cars are fast and exciting, but RC by definition introduces the human element. I'd like to have a competition in which the cars would race around a course in the gym. The course would include a section that is not visible to the radio transmitter operator. (An adjacent room, underneath the fold out stands, maybe a cardboard maze)

The cars would be under radio control where they are visible. They would be under autonomous control where not visible.

The winner of the race is the car that navigates the complete course in the least time.

Ken

[Andrew Schreiber]

http://ttjcrew.com/?p=91

Similar to that at all? Obviously that was done using a cheap car but a more expensive one would work just as well. Actually I think they are planning on it as soon as we can spring for a more expensive car.

Obviously instead of using an H-Bridge you might want to use an actual speed controller.

[kenjones1935]

Yes, similar to that Tech Junkies video. I am hoping to keep the speed capability of the RC car or truck. I am hoping to combine RC controlled racing with autonomous controlled racing. First I need to pick a micro. What do you all know about the Arduino? Could I have two power supplies? A single nine volt battery for the Arduino and a 7.2 volt battery pack for the more powerful DC motor.

Ken

[Andrew Schreiber]

Of course you could have two power supplies, btw the arduino runs off 5v most of the time. Add some other sensors and you should be able to run at pretty decent speeds. Or buy a better GPS unit and get faster updates. Much beyond that I can't tell you.

[Andrew Bates]

Over the summer I was playing around with using an arduino to interface IR distance sensors and RC control of an RC car. The idea was that the car would be "un-crash-able" because when an IR sensor "saw" something it would limit the amount of power the motor was getting. Since the RC car I had simply used PWM from a receiver to a motor controller I just put the arduino in between and then the plan was to modify the output to the motor controller based on the input from the receiver and whether or not anything was in the way. Unfortunately I never got around to finishing the code, I'm more of a mechanical person. Here's a pic:
http://twitpic.com/7039y
http://twitpic.com/70371

Good luck in your endeavor and if you need a cheap but good micro controller I personally love the arduino. Arduino website:
http://www.arduino.cc/

[Greg McKaskle]

This isn't RC cars, but it may be close enough, or it may spark some ways to get this implemented.

I think your biggest issue will be selecting sensors. I was in a competition years ago at Hanover Fair that took RC cars and attached a weak RF transmitter circuit. They had butcher paper on the floor with a race course marked out in black. Under the black tape they had a wire antennae snaking around the inside of the track.

Next to the course, was where you attached your computer to the wire leads of the antennae so that you could sense the RF signal strength and determine how far the car was from the inside of the track. You were also given the RC remote with the pots removed. You were able to send an analog voltage to the remote to control forward speed and front axle orientation.

This wasn't running on the vehicle, but you were only given a few hours to take one input -- not a great one -- and control two outputs to send the car around the track as fast as possible. In the end, this is the same as driving a car by looking out your side window and following the yellow line.

It was fun, challenging, but didn't involve targeting a tiny processor. Most teams of engineers had stuff going in a few hours. Of course most of the cars looked like they'd get pulled over and the driver would be given a breath test.

A related challenge is to do line followers. They can be done with any of the kits you mentioned, not to mention LEGO NXTs. The light sensor is easy to use and understand, and in the end the principles can be applied to other sensors to scale things up. There are lots of youtube movies showing results. Some of them are pretty impressive. This one is probably too easy, but you may be able to judge interest from the movies.

Greg McKaskle

[kenjones1935]

Here's my idea. It is beginning to take shape.

The underlying purpose is to interest middle school kids in STEM.

Hobby level RC cars are technically really neat but the engineering is mostly cut and try. Missing is an element of formal language combined with intent. By formal language I mean a "blue print" a "recipe" a "musical score" a "program".

I suggest a competition, a race, to be held in the Longsjo Middle School (Fitchburg, Mass) gymnasium plus its lobby. The racing vehicles are 1/10 scale RC hobby level cars or trucks. The race course is delineated on the basketball court by four inch plastic flexible conduit and maybe some traffic cones. The course extends out into the lobby to which there are two doors the width of the basketball court apart.

Inside the lobby is out of sight for the kids handling the RC transmitters. The regular lights are dim in the lobby. A bright light is placed in the doorway that leads back into the gym. The cars must find their own way back into the gym.

Let's guess three or four cars racing each other. The first car to complete three laps wins.

Can I build a car system robust enough to withstand the violence and simple enough to program? I am thinking of a simple language like ROBOlab or Terrapin LOGO. Both of these can easily follow a black line with a light background. I have done that. I think they could also easily find and go to a beam of light.

What do you think?