My first robot

[Geoffrey]

Hi, I'm planning on building my first robot sometime before the end of the year, and I'm going to be buying the following:

12 Tenergy Premium AA 2500mAh high capacity NiMH Rechargeable batteries
1 Sharp GP2Y0A02YK0F Analog Distance Sensor
1 Pololu Ball Caster with 3/4" Plastic Ball
2 2-5/8" plastic Black wheels Futaba servo hub
3 Power HD High-Speed Digital Sub-Micro Servos DSP33
1 Axon Microcontroller

In your honest opinion, what have I done horribly wrong in picking these materials, and what have I done right?
I'll be building a basic, smallish, differential drive robot that uses a distance sensor to decide which way to turn to avoid walls.

[rbtying]

Sub-micro servos won't be able to drive your wheels anywhere. 

[Geoffrey]

Then how's 3 Power HD Micro Digital Servos HD-1581HB?
Or do I still need more torque?

Also, dumb question, but to connect the sensor to the controller, do I need male-female, or female-female terminators?
Nevermind, I just realized...

[knossos]

Sounds good to me except the following:

12 Tenergy Premium AA 2500mAh high capacity NiMH Rechargeable batteries
3 Power HD High-Speed Digital Sub-Micro Servos DSP33
3 Power HD Micro Digital Servos HD-1581HB?

Is there a reason you will be getting 12 AA's?  Are you looking to power the servos separate from the Axon, or are you just looking to have a backup battery pack?  A single battery pack is more than capable of powering 3 servos, the Axon, and the Sharp IR rangefinder.

Secondly, is there a reason for going with Micro's and Sub-Micros?  With the wheels you plan on getting, you will have more than enough ground clearance for regular servos.  For example, the HS-311 is half the price and has more torque than the Micro's you have listed.  They aren't digital, but do you have a need for digital servos?  Also for inexpensive lightweight servos to mount sensors on, I use SG-90's.  If you shop around you can get them for as little as $2 USD shipped.

[rbtying]

@OP:
It's not about torque, its just that servo wheels are designed for normal-sized servo splines, and won't connect to micro/submicro ones.  Digital servos have better angular control, but for wheels, you don't really care about that... just build some encoders later.  An HS-311 should do fine, as knossos said. 

As for the batteries, I thought that the point was to have 3 sets to swap in/out... correct me if I'm wrong?

[Geoffrey]

Yeah, I spaced. Getting the HS-311's.
And I'm swapping the 12 batteries for a single 6v pack.

And no need to pay extra for continuous rotation on the servos as I can modify them for that for free right?

[rbtying]

Yes, that's right, you can modify your own servos easily enough (There's a tutorial on it in SoR that's pretty nice and detailed)

Your robot sounds pretty fun.  Be aware, though, that the output from a Sharp IR rangefinder is nonlinear... I believe the GP2Y0A02YK0F (20cm-150cm?) is something like 65*voltage^1.10 for reasonably accurate readings.

[Geoffrey]

Also, where can I get a hitec cable that will connect to the sensor and axon? I am having horrible luck finding cables.

[knossos]

A lot of sites sell the 3-pin JST connector for the Sharp IR rangefinder.  For example RobotShop and Sparkfun.  Also, if you're just looking for wire, there is this wire from ServoCity that works fairly decent (its reasonably flexible and durable).

[Geoffrey]

Okay, thank you so much everyone, you're awesome.

[Metal Slug 2]

I get my sensor cables from hobbyking: here
They have a futaba connector, which is similar to a hitec one.  But they will still plug right into the axon's header pins.

Just solder the lead wires right onto your sensor (ex: potentiometer)