TOday we picked up theDX6i and rx. we grabbed ONE servo, because hobby shop had pretty much nothing. It's a 322HD. However, I didn't get a battery. I assumed it would have come with the Tx and Rx.
cool, i really like the Dx6i and it is great for robotics.
Well you can modify servos for continuous rotation to use them as wheels. The thing with this is when you plug a modified servo into the receiver and turn it on it will turn fast and not really react to stick control. what you have to do is go into the menu options and put the sub-trim of the channel you are using to maximum/minimum( what ever way slows down the servo) when you have done this it will still turn slowly, from here you should be able to use the trim tabs on the sides to stop the wheel completely.
you can also use the features of your radio to mix the control onto one stick making control easier. although it will take up more channels. I am currently working on a way of plugging the servos into a micro controller and from there send a signal from receiver to condense the controls down to 2 channels and 1 stick. when this is done i will post how to do it.
I will upload a video to youtube showing how to setup servos and an RC transmitter if that will help?
If you want to go for a motor there are motor controllers called Sabre tooth motor controllers from a company called dimension engineering. you can get a version specifically designed to connect to an RC receiver. then you just have to find some appropriate motors and hook it all up. this will be a way of simplifying the set up but it is more expensive than going for a servo.
if you go for a servo you have to either chose a servo with high enough torque or keep your robots under that torque for them to handle the weight. and I have always found to allow room to add a lot more weight as things generally come up heavier than what i expect them to be.
A for the weight, if they are going to be smaller robots I would expect them to be around the 5 pound mark. but compile a list of all the things you can think of that you are going to incorporate onto the robot so you have a rough idea.