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FEZ Cerbot Line Follower


#1

Since I got the FEZ Cerbot I have been wanting to implement a line follower, but it has just never happened. Well this evening I decided I needed a break and here are the results from my first attempt.

I will post the code once I have played a bit more, I would like to see if I can improve the navigation of sharp corners.

Right now the logic is very simple, if the reflection on one side drops below a threshold (50%) I speed-up the opposite motor and slightly reduce the speed of the other. The motor speeds do not immediately return to the default speed once both sensor are on track, they adjust back to the default speed over time.


#2

Very cool. Did you notice that the rounded front is the exact same size as a pop can? Can you try to push one around? Maybe you can make it fetch you a beer? :wink:


#3

@ Gus - I did notice that, being the lazy bugger that I am I had it fetching the baby bottles :slight_smile:
Btw. I just posted the code to codeshare with a new video, the routine is improved and the bot is navigating the route faster.

Here is the improved routine in action


#4

Nice job!

The kids & I were playing with my Cerbot during the Christmas break and made a physical version of an iPad game they were playing. Basically, I put a Joystick module & button on it. They could program in directions for it to travel by pushing the joystick in a direction and then pushing the button. When they were satisfied with their programming they could then push the Joystick center button and it would follow their commands. We used plastic cups as a maze for it to try and navigate. Without encoders, it took a bit of software tuning to get it to go straight enough but it was enough to entertain them. I’ll try to get a video together. The current code is here.


#5

@ ianlee74 - Thanks.

Your project is cool, it would be nice to see a video of that. When I read it I thought of those robots that where controlled by Logo. It would definitely require wheel encoders, but it would be nice to be able to enter a few commands using the key pad module and then send the robot on it’s way.

Are there any wheel encoders that would fit the Cerbot?


#6

[quote=“taylorza”]
@ ianlee74 - Thanks.

Your project is cool, it would be nice to see a video of that. When I read it I thought of those robots that where controlled by Logo. It would definitely require wheel encoders, but it would be nice to be able to enter a few commands using the key pad module and then send the robot on it’s way.[/quote]

I’ll try and get something up tonight. I tweaked the acceleration parameters for each wheel via trial & error so that it travels fairly straight then I just used sleeps to let each instruction run the same time which gave me a fairly predictable distance. It definitely isn’t going to win any competitions but we had the whole thing up & running in under an hour. Gotta love Gadgeteer!

I haven’t looked but there should be some options. I’m surprised GHI isn’t selling this as an add-on.


#7

Wheel encoder is really issue, can not yet find the solution for cerberus