First off I am a complete noob. I have an Arduino and made an LED blink and fade so keep that in mind.
Well, you're off to a good start!
I have a little bit of programming experience. higher level languages.
That will come in handy!
I have very little electronics experience. Can read a resistor.
Then you'll want to get some; I recommend picking up a copy of Grob's "Basic Electronics" (some older edition, this is a textbook, and new editions can be expensive); its basically the book for EE101 type courses. Plenty of explanation, theory, math, and practical use regarding, well, "Basic Electronics". Starts with "what is an electron" and moves from there.
I want to make a remote controlled Lawnmower / ice fishing shanty mover. I know! "What?" -- In the summer I want to push/pull my mower around and in the winter I want to push pull my ice fishing Clam Shell hut around on the ice.
Ok - not to dissuade you, but what you are about to try to build will not be an easy project; really its not a beginner's project, but if you are willing to take some time on it, you likely can do it. Realize that you will be working with powerful motors, and batteries that can pack a punch, so you need to think "how can I prevent this thing from going out of control"; think manual kill switches, heartbeat monitoring, watchdog timers, and dead-man switches. Realize that you need to design this up front, before any of your other control systems, if you want this to be somewhat safe...
Also - in addition to the above book, I could also recommend a host of robotics books that could help you along the way...
Lawnmower -- I have a push mower to tear apart and use.
Motor -- I have an old three wheel scooter(older than the ones you find at stores etc.) It has a working 24 VDC motor (don't know the amps) It also has a 12VDC type of magnetic brake - I think. If I apply 12vdc to the one wire it releases the brake. If I apply 12vdc (I don't have two batteries yet for 24VDC) to the motor it moves the one wheel. The electronics on the scooter (controller) are fried or at least don't work.
Ok - if you plan on having any kind of PWM speed control of the drive motors, you will -have- to buy a motor speed controller. For your motor, you need to find out what its current needs are for stall current (shaft locked) and running current (free shaft - also called a no load current; this would be the motor only). Hopefully there's a sticker or something on the side of the motor that gives this information; you need to find this out.
You will want to size your motor controller to be at least (plus 10-15 percent) the size of the greater (stall) current needs. Say the motor stalls at 100 amps; you would want a controller that could handle around 110-120 amps. Hopefully your motor won't pull this much - high-amperage controllers are not cheap (neither will the batteries) - for instance:http://www.diverseelectronicservices.com/html/motor_controllers.html
(note that I have no stake in this company, nor have I ever ordered from them - its just an example; I encourage you to do your own research on motor controllers)
Depending on the amperage requirements of the motor, you may be able to use relays to control it, provided that the "top speed" isn't anything crazy (because with relays you can't really control the speed of the motor); the relays you will need to use will once again depend on the current required by the motor - this will determine what the relay's "contact rating" will need to be. Hopefully you can find 12 volt relays that will work, but if not, you could get larger 24 volt DC contactors (if you need to handle a LOT of current).
Regardless of the controller, you will also need to design the power distribution system; you'll need to take into account how much power the motor uses, plus whatever you use for steering (more on this below), plus whatever for the controller system (the Arduino and anything else - though compared to the other parts of the system, this will be tiny; figure 2-5 amps max). Once you know this, you'll be able to size your battery.
You will want an inline-fuse/breaker for the whole system, and if the 24 volt system is two 12 volt batteries in series (likely), you may want to have both a 12 volt rail and a 24 volt rail, along with your ground rail. Use bus-bars for AC circuit-breaker cabinets, and color code with dabs of paint on the ends (you might also want to match color coding with your wires; it will help immensely to sort future issues). From the rails to circuits, add secondary inline fuses/breakers.
The cool thing about the scooter is that the platform (seat, foot rest, front wheel, steering pole, etc.) is removable which leaves just the motor attached to a 1" square metal frame with a short 4" piece sticking out the front that goes into the front part and is secured with a pin. I think it was designed to be taken apart into two pieces to put in the trunk of a car for transport. It seems powerful enough for what I want to do.
Once again, please realize that this power can cause bodily or property damage should it go out of control; please think about your safety/recovery system first, before anything else. This is one piece of the puzzle that many people neglect until after they need it (or until the end of the design), at which point it is very hard to put into place in an already running system (this is true for just about any system you can think of, hardware or software based, by the way!).
1. So here is the idea that came to mind. I don't want to destroy this thing but rather hook up the Uno to it to control it (eventually from my iPad/iPhone) you know; forward, reverse, stop, speed. Then after I get motor control I want to drive it around sitting on it. Next, I want to build a 1" metal receiver to hook it to a push lawnmower. and drive that around. Lastly, I want to unhook it and hook it to my ice fishing shanty which will also have a 1" receiver as well.
When testing this thing, once you get it to the point of rolling, I recommend you start with "wheels-off-ground" to verify the operation of all systems (including all safety systems) as you work on and debug your code. Doing so will help prevent unexpected surprises (which may still occur - which is why you build in the safety systems first).
A regular all around helper bot with controls I know how to use. This seems the easy part.
The Hard Parts:
2. For the Mower and unmanned riding I want to come up with a way to steer this thing. So I am researching gears and motors etc. I do have a cordless screwdriver to tear apart first and see if it has enough torque to turn a gear (forward/reverse) and if it is sensitive enough to gain good direction control. I think the screwdriver has variable speed so I think it is slow enough.
Unlikely, but you can try it; you'll probably strip any gears it has, unless it has a clutch mechanism of some sort. My advice would be to cut your losses now, and buy a linear actuator (with whatever extension length needed to move the front wheel in the full left-to-right arc) - for instance:http://www.firgelliauto.com/
Remember that you may have to either buy one with limit switches, or implement limit-switches yourself to prevent end-of-travel jamming; you may also want to get one with a built-in potentiometer or other sensor to determine where along the length of travel the actuator is (and hence, what direction the steering wheel is pointed, thus the angle of turn).
There are other options available (Servo City has some interesting geared systems), but really a linear actuator, or some other kind of heavy duty geared motor and transmission system is going to be needed.