Let's Make Robots!


i got the 3pi robot from my friend for yet unspecified time :) so i plan to play with it a bit, put some more sensors on top and as it is usual with my projects make it able to follow line with obstacles course as well as navigate maze. i had to come with some name though and as it will be slightly altered kit i decided to go for the next letter in greek alphabet - Rho.

so far i basically finished work on the pure line following part - robot is able to follow black tape on white surface at the speed of 250 (thanks to the PID with tuned up parameters) as well as look for line, when it is lost. i added video of the speedy line following, no gap on that one though.

1. buy additional material/parts i need like pin headers i ran out of etc.
2. add sharp distance sensors for detectng obstacle in front and on the side of the robot - both for obstacle avoidance as well as maze wall detection. this involves adding some plate on top of the 3pi to be able to put sensors on it without having to solder it to the board itself.

1. obstacle detection/passing
2. test/tune for ramp/tunnel/etc
3. maze navigation...

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i tested Rho on the track for offline contest mentioned elswhere on LMR.
here is the video, it captures 3 laps, resulting in approximately 7,46s per lap. i added video to the topmost post.


i added two sharp sensors from pololu: one 10-80cm front and one 4-30 on the right side. with those, the bot should be able to detect obstacles as well as navigate in maze, hopefully. :) i have all the components i need for building the maze, so in short time, i will be able to build some testing...

here is the picture of the bot with new set of "eyes":

as you can see, there is some sort of platform put ontop of the bot just above the batteries, it is cut from model shop plywood, held in place by three screws (i didnt find such thin and small standoffs. sensors are attached with double sided tape.

HW is basically done, now i have to get to those SW TODOs:
1. obstacle detection/passing
2. test/tune for ramp/tunnel/etc
3. maze navigation...

no HW changes since last post. i only had to get another pack of batteries, as to sharps together with IR for line seem to consume a lot and ate VERY sensitive to decreased capacity => voltage returned to analog pins decreases rapidly.

video with obstacle detection and navigation around is in the main article. as you can see, derivative constant is too big, thats why it shakes, will have to tune that...

1. work on the line detection after obstacle
2. test tunnel/ramp
3. maze navigation

i added ability to follow the right-hand wall in the maze, video is attached to the original post