This is an updated build based on a previous Instructable. This one is easier to make and looks a little better. In addition, some new building techniques like using magnets to attach the Lego maze are kind of cool.
The project is for a web site that lets you control this device over the Internet. As before, since it's a web site with latency (no Wiimotes), there are only 4 commands: Up, Down, Left and Right. So the maze itself has to be designed carefully to work with only those primitive commands, and those designs are covered here.
This Instructable is about the mechanical build of this project. Other ones cover the web control. For local control with an Arduino, this Instructable has the controller design and code to make it run. I have also attached the latest version of the local control code to the last step of this Instructable.
Metal, Wood & Misc.
6.5" of angle aluminum 1.5" x 1.5" x 1/16" thick
4 feet of aluminum bar 1.5" x 1/8" thick - 1/16" might be OK too. I had some nice anodized bar, but any kind will do.
Plastic sheet - 10" x 10" x 1/16" thick. I recommend polycarbonate/lexan since it's less likely to crack
1x Lego bricks
Marble - the right size marble for two Lego studs is 9/16" (14mm), which is common on board games. Land of Marbles has many colors and styles available in this size.
1x4 pine - about 5 feet
Servos - Hitec HS-5645MGs are recommended
I use McMaster-Carr to order the stainless screws, nuts and washers, but you can get most of them at a local hardware store. The wood screws were from the local home store.
(4) 3/8" long #8-32 pan head socket screws for the X Axis brackets to plastic mount
(4) #8 flat washers, split lock washers, and hex nuts - Keps nuts can be used for these instead
(8) 1/2" long #8-32 pan head screws for the Y Axis bracket
(8) #8-32 Keps nuts
(4) 3/8" long #6-32 pan head screws for mounting the servos (two per servo)
(4) #6-32 split lock washers + hex nuts
(2) 1/4" long #4-40 pan head screws for the X Axis servo horn
(2) 3/8" long #4-40 pan head screws for the Y Axis servo horn (the aluminum is thicker)
(2) 3/4" long #4-40 pan head screws for the pivots
(6) #4-40 nuts - maybe a couple split lock washers and flat washers for the pivots would be good.
(8) 1 58" long drywall screws
(4) 3/4" long #8 mod truss lath screws