Looking at this guy's site:
http://tlb.org/scooter.html
and the stuff he used, a DIY segway could be built completely from the KOP (except maybe some of the frame.)
Going down the list:
Code:
Motors Brushless servo motors with neodymium magnets. "The highest-power motors for their size and weight ever put into mass production". Conventional DC motors with gearbox, widely used in powered wheelchairs. $286 each from National Power Chair or from Robot MarketPlace.
CIMs
Gearbox "Like a precision Swiss watch". Engineers designed the "meshes in the gearbox to produce sound exactly two musical octaves apart." Part of the wheelchair motor above. When going up a ramp, they sound kind of like the starter motor on my old Dodge Dart. Rrrrr-rrrr-rrrr-rrrr.
Banebots planetary
Batteries 2, 60-cell custom-designed NiMH packs producing 72 volts. "the highest power of any currently available chemistry". 20, 6-cell NiMH packs made for RC cars. They have "IDEAL SOLUTION FOR RC TOY" printed on them.$15 each from Powerizer.
Robot battery (maybe something smaller would be needed)
Wheels Wheels are "sophisticated engineering-grade thermoplastic." Tires by Michelin, with a "unique tread compound (a silica-based compound instead of traditional carbon-based materials)". Wheels are stamped steel. I think they're made for utility trailers. Tires made by Cheng Shin tire works. They make startlingly loud squelching sounds on tile floors. Tire and wheel are $79 each from NPC, and hubs are $20 each.
KOP wheels should work, maybe something bigger?
Controller "Sophisticated controller boards from Delphi Electronics" with "Texas Instruments digital signal processor, monitoring the entire Segway HT system and checking 100 times per second." An 8-bit microcontroller from Atmel, running code written in C using floating point arithmetic. It sends speed control commands out the serial port at 9600 baud in ASCII to the motor driver. $10 from Digikey.
FRC controller would be overkill. VEX controller could be used.
Or spend 10 bux for this controller (the problem with this would be the lack of interface for the Victors, whereas FRC or VEX would work directly)
Motor Driver "a set of 12 high-power, high-voltage field-effect transistors (FETs)". The controller has 16 MOSFETs and can handle way more current than my batteries can supply. Made by RoboteQ, it's $485 from Robot MarketPlace. It's a popular part for use in Battlebots.
IFI Victors
Gyroscope "packed with five solid-state, vibrating-ring, angular-rate sensors" One ceramic rate gyro, of the same kind that's in your camcorder (to detect your hand jiggling and stabilize the video) or RC helicopter (to stabilize the tail), and a 2-axis accelerometer to correct for drift. $149 from Rotomotion complete with the Atmel microcontroller.
KOP gyro
Structure Plastic and aluminum in smooth swooping shapes. "Chassis withstands 7 tons of force." Two pieces of aluminum plate with holes drilled in them, and a standard aluminum extrusion for the handle.
KOP metal could be used, probably other stuff would be needed though.
Safety features Everything is dual redundant. For example, "in the unlikely event of a battery failure, the system is designed to use the second battery to operate the machine and allow it to continue balancing until it is brought to a safe stop." There is no redundancy or backup system. It is not even robustly made. Loose wires literally dangle out the bottom. In the fairly likely event of the software crashing, a wire coming loose, a component failing, or the batteries running low, the wheels will stop and the entire kinetic energy of the system will be used to accelerate my head toward the ground.
Not sure about this one :p
Just an idea
Jacob