Code? Well if I knew how to make a good program that runs it.. I spoke to a friend of mine that is extremely good in electronics and programming, and he said that the most optimal solution to intuitive control would be to insert strain gauge in your bones. But in this world that is not possible and probably never will be. So there's that. 

See, the problem is that the ExoArm must read the weight of object you lift before it even tries to assist you in lifting. And that is so hard. So hard. Weight changes depending on the angle of fore arm, how your arm is angled in respect to earth, etc. I'm not saying it's impossible, but it would really take some time to make this happen. 

SO if you are looking to make one yourself, and are not that good in programming you should just use 2 buttons. It's astronomically easier. 

MUSCLE SENSOR:

Short answer. No. Why? Because. 

Just kidding. I tried using it and it did not work as I thought it will. Not even a bit. See the problem is that when you put the electrode on your biceps, you can trigger it just by stretching your skin. it causes so much electricity that it false triggers and device thinks that you send a muscle signal. So when the Exo-Arm is fastened to your arm, the belt will stretch your skin, especially at the biceps. What happens? Exo-Arm flexes, but does not let go, because it thinks you're still sending signals to the biceps when the only signal is your stretched skin, if that makes any sense.

Where to put all electronics?  

I spend so much time trying to come up with a decent place. Perhaps a good starting point would be a little "backpack thingy" that sits on your shoulder or maybe even a small backpack. See the problem are batteries. They are rather heavy and make things difficult. We must also keep in mind that this should be as low cost as possible, so no fancy ExoBacks or similar things.