Hello. We are planning on using a spektrum radio control to control a robot, but we have a few doubts. is the signal from the output of the receptor a pwm signal or how is it? does it depend on the channel? would we need a motor controller to control the motors or could we use an h bridge?
We also considered using xbees. would it be better to use xbees?

 

I would personally use the XBee. This would provide essentially a wireless serial connection. You would need a microcontroller of some type on the robot to process the serial commands from your controller, which could be a laptop with another XBee.

As far as your motor question, it depends on the motors. If you are using standard DC motors, often found in toys, than you would use an H bridge. Servos can receive their position signals from the microcontroller directly. Stepper motors require a bit more to make them work, brush less motors require a different approach all together.

Could you give us some more information on what exactly the goal is? Once you have a goal that you need to accomplish with the robot, then you can look at the hardware required to achieve that goal. Once you know what hardware you are using, then you can look at what it will take to operate that hardware.

Also, be careful not to stray too far off the topic of RF and communications since that is where this is posted in the forums. Your project will become very frustrating, very quickly, if you don't have a decent plan put together. Good luck in the project.

Cheers