Arm by Nicholas H

 Arm’s arm is made out of legos and duplos. I also put a rock on the bottom to keep it from tipping
over. Arm uses two motors; one motor is for up and down movement, and the other motor is for opening
and closing the gripper. Arm’s brain is made up of two H-Bridge circuits, each of which controls the
direction of one of the motors. I connected each H-Bridge circuit to two buttons. This makes a total
number of four buttons to control Arm. Right now arm is pretty useless because it can only pick
something up if the thing it wants to pick up is in the right spot, and once it picks it up, all it
can do is lift it up and drop it. I got another lego motor for Christmas though, and I plan on
making an Arm2, which would be able to rotate. I also plan on adding a pressure sensor onto the
gripper and making it so to close the gripper you just press a button. A circuit would make the
gripper close until there is a certain amount of pressure on the pressure sensor. (because the
gripper had closed on an object) Then it would stop. 
One problem I had was connecting the lego motors to my circuit. I found out that if a wire is stuck
in one of the little holes at the end of a lego wire, it gets connected to it. I still had problems
though, because this connection is a bad one. I can’t remember how long it took me to build, but I
think it was around a week. It didn’t cost me any money, because I already had all the supplies.