Mechanical arm

A cool arm that can pick things up and works great inspired by Emily the engineers arm she built in one of her videos.Please remix and improve it if you can because there are many ways to improve.It works but my soldering is very badIt is very easy to assemble first you screw the arm bits onto the 2 metal M4X200mm threaded rods then you put the motor into the motor housing the you solder the the motor to a H bridge then to a battery so when you press a combination of the 4 buttons the motor rotates each way then you screw on the long part with some M3 bolts of any length up to 20mm next you screw on the head with some more M3 bolts next you assemble the grabbers with some M3X24MM metal rods then you slot the gears into the head then you screw on the head cover with some more M3 bolts then you are done!