"Miranda" - Laser Scanner using Wii-Mote Camera, Xmas Bauble & Propeller
I present to you "Miranda" , a laser scanning Robotic system using a Wii-Mote Camera and Festive Reflective Xmas Bauble.
My previous "Halo" Experiments have been progressing at top speed....... and required a fitting Robot for it to be fitted too, it was a case of "Honey i shrunk the robot"
I wanted a friendly Xmas Table-Top robot (a lady friend for Brian) ....... that could negotiate around the Xmas Turkey/Nut-Roast, stuffing, Cranberry sauce etcetcetc.
The Videos contains the Build information and the scanner out_putting raw data to Debug monitor.....
.....also assorted trial and error videos and landmarks during build....
Why "Miranda" ......see the last Video......
Before you wear your mouse out trying to find the Autonomous Video (there aint any yet)........ yet
Story so-Far :-
Yes thats a mesmerizing sparkle in her eye..
Top is the Continous Servo driving a Mirror on a Pivot
(so you can adjust the size of you Halo on the floor).
Beneath that is the Low-Power Laser.
The Golden-Reflective Xmas Bauble ...or the
" Pièce de résistance "
Hacked Wii-Mote on neat breakout board
PPPB Motor driver board
I highly recommend this board ....solid...flexible...purple.
... Chris describes it as an Under-board....butbutbut....
....its much better showing itself off on top YAY
This is why the MDA Propeller RBBB Board.... sits underneath.
Chassis is also from CTCs RocketBrand laser cutting service
........Laser cut Plexiglass callling out for side lighting....
With 2 x GM10 motors......ok next time plexiglass will get cutouts or mounting brackets.....(no hot glue)
Green coaster is one-half of a smoke bomb firework .... slippery plastic....works wonders.
Chassis works well and drive tracks straightline without software adjustments YAY.
My first attempt to make sense of the data ...
... circa 1024 dots (no quoting here please) around a 200mm (new money) 8" (old money) laser circle.
The output debug screen below shows just half of the circle and i have reduced the number of sampling points for clarity.
In a perfect world with no obstacles the robot will see a perfect circle......
.... In the other world obstacles prevail..... you can see odd pixels missing and others off the track..
These odd pixels are in fact objects being detected... sometimes they are pushed in or out of the circle ...other-times there are eaten by the object....
Here is the general detect idea.......
... Wii camera likes to see dots of laser light so its really smoking when there are no obstacles....
... When an obstacle is spotted the wii camera loses the laser dot (because the object blocks the reflection back to the wii camera), this presents a problem because the wii reports back with null reading (and that is not "0,0" but "1023,1023")...so you have to log the previous last good reading (ie the one before the 1023,1023) , then the edge of the object is found YAY.
Software strategy is to not to find the object but to detect "Blanks" (wii failed to detect errors) in the field of view....
It works "ok" however if anyone out there has any other strategies that could work then dont be afraid to blog them below.
It works "ok" however if anyone out there has any other strategies that could work......
.....then i would be "all ears" to see them blogged below..