Date: Sat, 7 Jan 2006 21:32:26 -0600 (CST)
Subject: lasers disassembled ; fiberglass insect screening
X-UID: 119
Content-Type: IMAGE/JPEG; NAME="img2523.jpg"

The Walmart laser line levels are troublesome to disassemble as parts are 
glued in place. But the laser module does come out. There's a surprising 
amount of engineering for $7. I didn't expect this much complexity and am 
impressed with the quality. The rubber gasket between the laser head and 
the front bezel is a nice touch.

The laser head and secondary circuit board are really a single unit. 
Current regulation of a laser diode can be non-trivial. So I'm not going 
to mess with the electronics.

I have to disassemble the lasers as the housings are just too big and 
heavy. I have the idea to mount the lasers on the front wheel kingpins. 
This way, they'll track with the steering direction, like handlebar 
mounted headlamps on a bicycle. Also, with cameras mounted on the vehicle 
centerline, there's enough offset distance from the laser plane to give 
good triangulation.

Unfortunately, this is mechanically awkward to do. It moves electronics 
out to the end of the front suspension near the spinning wheel. Vibration 
and shock will be bad out there. There's not a lot of room either. Parts 
are shifting around as the wheels move up and down.

I picked up some vinyl coated fiberglass insect screening from Home Depot. 
The fan intake vent will be covered to keep out debris. I also have the 
idea to bend a Lexan shell over the robot and cover it with the screening. 
This kind of turtle shell idea is one I've seen before for robots, 
noteably CMU's Nomad. This should offer some protection.

I'm still not sure how I'm going to pick the robot up. I've had ideas for 
handles of some kind. It's too large to fit into any plastic storage bin 
I've seen. Without some way of packing the machine, moving it is very 
awkward. If I had to do this over, I might have designed the machine to 
fit into some standard size container. As it is, it is designed to fit, 
just barely, in the trunk of my car. A truck or van would be a lot more 
convenient logistically.