Need solution for electromagnets project

Projects General Guidance
1

Hello,

I am new to electronics I am trying to do a project but I am unable to find suitable design for it, I am using Arduino board for my prototyping, the project is, I made a matrix of 8x8 small electromagnets which is working with 12v and 250 mA, basically these electromagnets pushes a small neodymium disc magnets on other side.

I tried to drive this using 74HC595+ULN2803 combination for each column and I am able to drive them individually, but my problem is I need to also switch the power direction individually so that the electromagnet pulls the neodymium disc magnets back, now I am not able to decide how I can drive those individually with bidirectional power switch from code.

To get an idea this project similar to flip disc displays where the electromagnets try to push and pull the neodymium magnets so that the disc flips.

It will be really helpful if someone can give me suggestions over this issue and sorry for my bad English.

Thanks in advance,
-Prabhu

2

You need H bridge.

3

Hi Shpaget,

Thank you for your suggestion, H Bridge for each electromagnet might be very difficult to place it, since the matrix having 6mm diameter adjacent to each other, I was thinking is there any other way I can do it like:

Having two set of 74HC595+ULN2803 and connecting both the end of coil to two IC legs so that one set will give positive and another set will give negative power to the same coil, in this case I will have to make sure the other lead of the coil goes to ground and it won't fry my IC.

I am not sure is it feasible to do it, but I think other way is to have two coils on same core so that i can power up specific coil depending on direction, please give me your opinion on these.

Thanks,
Prabhu