
47:1 Metal Gearmotor 25Dx52L mm LP 12V with 48 CPR Encoder 

LIS3MDL 3Axis Magnetometer Carrier with Voltage Regulator 

AStar 32U4 Robot Controller SV with Raspberry Pi Bridge (SMT Components Only) 

LP 12V Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox) 

172:1 Metal Gearmotor 25Dx56L mm LP 12V with 48 CPR Encoder 

AStar 32U4 Robot Controller SV with Raspberry Pi Bridge 

HP 12V Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox) 

99:1 Metal Gearmotor 25Dx54L mm MP 12V with 48 CPR Encoder 

MinIMU9 v5 Gyro, Accelerometer, and Compass (LSM6DS33 and LIS3MDL Carrier) 

MP 12V Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox) 
Paul's dead reckoning robot
 19 August 2015For anyone interested in building a robot like this, our new AStar 32U4 robot controller includes most of the electronics shown here, on a single PCB. So if you use that, you can skip the breadboard and directly wire your batteries, motors, and sensors to the controller.
Paul's dead reckoning robot
 20 July 2015I have not made a wiring diagram (need to learn Fritzing!), but I still have the robot, so if there are any connections that are not clear in my post, I would be happy to check them for you.
Math on the Pololu website!
 27 June 2014Ben wanted me to post the details of the Gaussian integral, so here we go.
It's simpler to think about the full integral from ``oo`` to ``+oo``. Let's give that a name:
``lambda = int_oo^oo e^(x^2) dx``.
Then, instead of trying to compute ``lambda``, we work on ``lambda^2``:
``lambda^2 = ( int_oo^oo e^(x^2) dx )^2 = int_oo^oo int_oo^oo e^(x^2) e^(y^2) dx dy``.
We note that ``e^(x^2) e^(y^2) = e^((x^2+y^2))`` and rewrite in polar coordinates:
``lambda^2 = int_0^oo e^(r^2) 2pi r \ dr``.
Luckily, that integral is easy, since ``d / (dr) pi e^(r^2) =  2 pi r \ e^(r^2)``:
``lambda^2 =  [ pi e^(r^2) ]_0^oo = pi``;
``lambda = sqrt(pi)``.
Finally, since the Gaussian is an even function, our desired integral is just half of that value:
``int_0^oo e^(x^2) dx = sqrt pi / 2``.
Pocketsized USB charger adapter
 6 March 2014Thanks for the nice feedback, and please let us know when you post more projects!