While they are not nearly as complex as their self-navigating brethren, building line following robots is no simple task, especially when they are this small. The creation of [Ondřej Staněk], this matchbox-sized line following robot is quite impressive.
PocketBot’s 48mm x 32mm circuit board also acts as its frame, supporting the wheels, motors, microcontroller and more. The brains of the operation is an ATmega8 microcontroller mounted on the bottom of the bot. A pair of wheels are driven independently using a set of mobile phone vibration motors that power the bot at speeds of up to 0.35 meters per second. Line detection is achieved by using three different IR sensors paired with four IR emitters located at the front end of the bot.
PocketBot also has an IR receiver on its top side, which allows [Ondřej] to control the robot, tweak its parameters, or calibrate its sensors on the fly using an IR remote or his computer.
The PocketBot might not be the absolute smallest line following bot we’ve seen, but it’s pretty darn close!
Continue reading to see PocketBot in action.
[vimeo http://vimeo.com/6394938 w=470]
Now that is just cool! I was wondering how you connected it for programming as I see a 4 pin arrangement near the edge of the board (usb?) Then I read that he does it with the IR, now that is pretty cool!
Congrats to the people behind it! Wish we could buy this ready on eBay… ;-)
That’s pretty slick..
I can remember free-forming these out of soldered paper clips and LM339’s.. ;) Not nearly as elegant..
This is sweet! I could have a lot of fun with my dogs with this thing. :) I love how he can control it with the ir remote arrow keys.
How is he using the vibration motors for propulsion? Are the heads of the motors directly spinning on the surface of the wheel? I can’t really tell.
I would love to build one of these.
I read the build log in czech and he’s using neodymum magnet in the middle of wheel frame so the wheels are forced to stick to the motor axles. Very clever solution.
Reminds me of this guy. It took a while to find it again…
http://elm-chan.org/works/ltc/report.html
Wow, that’s a little bit too similar for my taste… But then again the older project doesn’t provide the source so courtesy goes out the window.
Well, there is a link labeled “Firmware” at the bottom of the page under a section labeled “Notes”.
Here is the direct link to the assembly code:
http://elm-chan.org/works/ltc/ltcsrc.zip
The Elm-chan’s project also implements P-I control and runs much faster and smoother. But I’m not saying that this one is not worth mentioning. What I don’t fully understand is why the author didn’t bother implementing I part of the PID.
@svofski: He probably thought that it doesn’t matter if it gets a constant error, as long as it follows the line. Also, he programmed it in assembly, so I guess that he wanted to do it as simple as he could… assembly is not that fun :P
@Pete: That link explains how he’s using the motors. Thanks for that.
Fascinating. An excellent miniaturization of a classic project, that Ir update feature would really make tunning a lot easier. Another good project.
It would look good if you left it in the match box with some holes on the bottom for the wheels to pock thru and a hole for the sensor.
Then invite a friend round and ask him if he can see where you left the matches, then turn the robot on when he’s not looking.
-“building line following robots is no simple task”
That’s supposed to be a joke, right?
This is an awesome project though. Mini stuff is always welcomed by me.
want!
video clearly states 0.6m/s, not 0.35m/s
0.6 m/s on straightaways, 0.35 m/s following lines – which is what this robot is built to do.
It actually states both AWE dammit someone beat me to it.
Love the way they embedded the connector headers as part of the pcb. (cheap and small ICSP)
Anyone out there with a compatible mini cable connector?
I was curious too. He’s using connectors for RAM memory, the PCI is too big he says. It’s on the pictures somewhere in the middle of this page http://www.ostan.cz/pocketBot/developement_diary/
Wow. His page goes into some more detail. Nice work!
Awesome project! Would be cool if it was modified a little to go inside a hotwheel car. Mini-Robot army anyone???
He’s made got a version 2 in progress: http://www.ostan.cz/PocketBot2/development_diary/
I just love the amount of work he put into this project, everything is so well taken care of and the whole thing feels finished. My respect. Now make it available as a kit at toy stores, or Sparkfun.
I like the use of a magnet to make a low-friction, adjustable “spring” to pull the wheels onto the motors.
wow, this is the cleanest design i have seen so far :) i love it
It is neat…but I wonder why the second version is still only two wheels. To me, the only point of something like this would be to stuff it into a matchbox car…and for that you need 4 wheels.