Hi everyone, I bought an arduino kit a few months back with the intentions of learning it and having a cool new hobby but I never really got too far with it beyond some basic LED things. I wanted to try it again and this time to motivate myself into learning it I invested some more money into things, I bought quite a few things so that I would be more motivated (rather than just spending money and seeing it sit). So I bought a lot of things but my intentions were to build an autonimous robo rc car, I could flick a switch and have it RC with joy sticks or I could set it to autonomous and have it avoid walls. I ordered some mecanum wheels from sparkfun (mecanum wheels are the main reason I wanted to learn arduino in the first place, so I could build an RC car with mecanum wheels, haha), I also bought some stepper motors to power them (https://www.sparkfun.com/products/9238) but am now thinking these won’t work as well as I had initialy thought because they don’t seem like they’re going to go more than 2mph (I don’t need the car to go fast, but I want it to be faster than walking speed at least!) but steppers make more sense than normal DC motors because they’re more precise, so some advice there would be cool. I also bought a seeedstudio motor shield v1 but I don’t really get how to use it I found this Motor Shield V1.0 | Seeed Studio Wiki but don’t get how to use it; specifically, which pins does the shield actually use for the motors, and how do I use the pins that it’s NOT using? I managed to get a ultrasonic sensor to read distances in inches using a few tutorials so I think I’m cool with that so far. I’m good enough at the coding for now, I’m remembering the commands for things and how to program most stuff using the normal arduino uno (not with the motor shield on it), I think my biggest struggle is going to be the actual hardware and knowing voltages and all of that stuff. I see topics here where people discuss all kinds of things I have heard of but don’t know what are (such as farads) and I’m not really sure when to use diodes and things like that, I bought a book (Arduino Workshop) and I’ve read the first 50 or so pages so I’m learning it all but like all of you experts, I have to start somewhere and start knowing nothing. So I look forward to learning and using this site as a resource to help me learn/concrete these ideas better. Thanks guys!
Robby
Hi Robby, and welcome 
It sounds like you're on the right track if you're working through projects in the book and have a decent grab-bag of parts.
specifically, which pins does the shield actually use for the motors, and how do I use the pins that it’s NOT using?
That motor shield uses digital pins D8 through D13 so on a Uno that still leaves a good number of IO options:
D0 & D1 Normally used for serial IO and debugging, but when you don't use that you free these up for use. Also useful for serial comms over radio (bluetooth, Bees, etc)
D2 - D7 General digital IO, D3, D5 & D6 are also capable of PWM
Analog 0-5 For analog inputs, and these are also addressable as digital D14 through D19 if you need extra general IO pins.
All I can suggest is keep pushing on with it, there's lots of fun and the glow of achievement ahead, and when you get stuck - shout out. There's lots of folks here to assist when you do.
All the best! Geoff