I'm making a Phantom Chess game where a computer and stepper motors move players around on a chessboard. The pieces are made with N and S magnets, and an electromagnet is to pull them around. I have a Gauss meter and tested a number (about 30) solenoids and found one that gave pretty good results and gave the highest flux reading of 1452 Gauss. (Commercial EMs that had a 5kg rating were around 300 Gx). The EM (it is a solenoid with metal core) easily pulled the players around with a 2mm sheet of aluminum between them. HOWEVER...there is more to go between the player and EM: a PCB with Hall sensors on it and a 2mm acrylic sheet. I tried it...doesn't work, distance too great, so I need more oomph! The solenoid pulls 250 mA at 12 volts and any attempts to raise the voltage only heats the solenoid up. I will be using an H-bridge to change polarity and likely PWM from an Arduino MEGA. Everything is in place and ready to go as soon as I can get the EM working, so I'm at the point where I want to build my own EM. I bought a roll of #38AWG magnet wire at 2381 ohms/km, I can make bobbins with my 3D printer and EM is only slightly constrained physically because it has to fit in the trolley that moves the players around, roughly 30mm x 30mm. (My current EM is 16mm dia x 30 mm. It sits on a spring to keep the magnet surface in contact with the bottom of the board. My players have metal surround base to concentrate the magnetic field downward to minimize side-to-side attraction (the moving player has to move between other players. Square size is 40mm. My project is here: https://www.raiderracing.com/Engineering/PhantomChess.html Skip down to 4th Build, because that is where I'm at.
WHAT I NEED: Information on how to wind the coil, a calculator so I can determine how many turns I need for the bobbin size. Calculating the flux reading is not necessary: I'll just make the EM with as many coils as I can, then TRY IT. I've also got some #42 wire coming from China. Everything I've seen on the web is how to make an electromagnet with a nail that attracts paper clips....
WHAT I NEED: Information on how to wind the coil, a calculator so I can determine how many turns I need for the bobbin size. Calculating the flux reading is not necessary: I'll just make the EM with as many coils as I can, then TRY IT. I've also got some #42 wire coming from China. Everything I've seen on the web is how to make an electromagnet with a nail that attracts paper clips....
