Hey guys, for my engineering course, we are build an autonomous watercraft with a self expanding debris recovery system. My job is the debris recovery system, and part of this system basically using a solenoid to expand the system. The idea is that a frame made of PVC piping, which will have a total length of ~500mm, will rest on the craft and to make it self expand, a solenoid will be used. I am planning on wiring up the solenoid to our micro-controller and programming the pin to send a short burst of electricity to the solenoid, which will in turn induce a magnetic field around the solenoid of a short period. There will also be a magnet which will be position on the frame, so that when the solenoid is powered on, the magnetic fields will oppose and it will create a force which will cause the frame to expand. That was probably really difficult to understand, so if you have any questions about it please ask. But the main question is, what is the best way to make a powerful solenoid? Like should i use a certain core and does length of the solenoid matter? At the moment i have 6 20mm*15mm magnets and a roll of copper wiring. Any help will be greatly appreciated And if there are any questions regarding anything, please ask.