Here is a robotics kit that comes with everything you need to put together a robotic exoskeleton. The EduExo Pro ships with an EMG sensor, servo motor with up to 6Nm of power, a mechanical spring, an Arduino, a potentiometer, and everything you need to get started.
This kit comes with a detailed handbook and teaches you new concepts as you assemble the mechanical parts, connect the electronic components, and program the microcontroller. This project is getting funded on Kickstarter.