I just bought an Arduino Mega 2560 r3 with a bunch of sensors, leds, resistors, etc... to mess around with. I also bought this hobby motor: https://www.sparkfun.com/products/10171
Now I am realizing that I probably need a transistor to make it work.
A) Is there a way to test that motor without a transistor?
B) What are the steps you take to pick out a transistor? (using the above motor as an example would be great)
C) What are the main things you look at when looking at a datasheet? (here is the datasheet for the hobby motor I have (201-A): http://www.sparkfun.com/datasheets/Robotics/hobbymotor.JPG
D) Any suggestions for quickly getting into working with motors and servos? (learning about external power supplies, transistors, etc...)
Here is a handy explanation of how to use a transistor.
It does say that the transistor it talks about, the BC547, is not what you want for the current drawn by a motor, but nevertheless it shows how to hook things up. It also indicates that the IRF520 is a good choice for running motors and such.
BUT..... they key thing to hooking up the motor is to use a diode as explained about half way down this page where it shows a transistor switching a relay... mentally change the relay to your motor.
Sorry I can't help with interpreting datasheets.... I'm sure someone here will help though!
Regarding testing the motor, well you can just jam the wires onto a 1.5V AA cell and it should run.
Servos are easy.... have a look here for that. But it's bad practice to give the servo its power from the Arduino- the red and black should come from their own source like a battery, and you need to connect the battery ground to Arduino ground.