Well, I’ve looked, but I haven’t seemed to have started a thread for this upcoming project, though I’m sure I posted about it…
Anyhow, here it is:
These are the motors:
At 25 ft lbs of torque, these buggers suit my overkill tastes just dandilly.
harborfreight.com/cpi/ctaf/D … mber=93449
This is going to be the main body:
harborfreight.com/cpi/ctaf/D … mber=91949
Steel is heavy, but I like being able to weld.
With the above motors, I highly doubt that weight will ever be an issue.
All of my projects thus far have been with aluminum.
Since I don’t have a TIG, I’ve spent a lot of time fastening bolts and nuts, which is not my favorite pasttime.
I’ll be using an idler wheel from Harborfreight and the 3" sports tires and hubs from LM (I’ll be getting some 3" industrial caster wheels from HF in case the sport tires can’t handle the bot’s weight.
I’ll probably be keeping almost the entirety of the drills intact, so I won’t need to mess around with idlers and such.
Stainless steel worm-gear hose-clamps will hold the drills down, and the strength of the drill itself should be more than enough to deal with the abuse that I throw at it.
Plus, keeping the drill intact lets me grip onto the hub directly with the keyed chuck of the drill.
There’ll be 3 EZ ultrasonic senosors from Sparkfun on the front of the car.
Eventually, I’ll also get a CMUcam2 (not the +) and mount it on a pan and tilt.
Around the camera, I’ll place a universal oil filter socket:
amazon.com/exec/obidos/tg/de … R&v=glance
What?!?!
An oil filter socket?
Yup.
Here’s my idea:
On each of the 3 legs of the socket, I’ll mount a laser pointer.
Then, on the back I’ll attach the rotating nut onto a servo’s horn.
And, as before said, I’ll whack the camera’s module in the middle of the socket.
Then, I’ll be able to rotate the legs of the ratchet, which will move the laser pointers into a circle of varying radius.
This effect I’ll use to create a cute little way for the car to “focus” on objects.
I’m hopint that it’ll look somewhat like an iris dilating and contracting.
When I tell the cam to start tracking a certain colored object, I’ll have the servo dilate the laser “iris” wide.
Once it’s locked onto the stationary object, it’ll contract the iris.
Then, when the object moves, the iris will again dilate a bit until it moves the pan and tilt to again lock onto the object.
Aside from those neat behavioral tricks, it should also serve to measure distance really well.
To do this, I’d just position the iris at fully dilated.
If I remember rightly (my brother has one of these buggers), the legs of that wrench have about a 5 degree bend.
So, I can use the camera to count the pixels between the center of the image and the red dots.
Having 3 pointers will give me 3 readings that I can average together to minimize mechanical errors.
Then, I simply do a bit of trigonometry (tangent of 5 degrees / average number of pixels to laser dot) to get the number of imaginary pixels in between the bot and the object.
That might not seem like it’s useful, since it would be very hard to translate that into the distances that we are used to, but methinks it’ll be more than enough to do neat things like building a 3D map of the environment.
It should definitely be enough to get this bugger to chase down an accidently-yellow-spray-painted cat.
