Hi. You said you have found a circuit for this somewhere? Please post a link to that. I cannot imagine how such a circuit as you describe could work, especially using relays!If I were designing a circuit for 64 electromagnets, I might use 8 tpic6*595 shift registers if the current required by the electromagnets is low enough. Otherwise 8 74hc595 shift registers and 64 MOSFETs.
Sorry, I don't know how to draw a standard one.
I have research some documents about MAX7219. Successfully rebuild a Electromagnets Matrix replaced the little LED Matrix.
I add 16 relays before the electromagnets pins
(Input: 3v-32v, Output： 200V Max）
The segment pins source current and the digit pins sink current. Do you understand that?
What value have you used for the Iset resistor? This will limit the current the chip can deliver.
MAX7219 has a little resistor, but in Matrix, it has no one.
6, I connect INPUT side of relay with every electrodes and MAX7219's 16 pin jack7, OUTPUT side of relay connected switch power supplies. in this way, Matrix has enough power
I think the source is power supply, and the digit is controlling.if I have not misunderstood.
if he does as is recommended and has shift registers controlling the relays then he can control which one magnet is on at any time. He can not control more than one magnet to be on at any one time. This is because the speed of the multiplexing...
1) What relay do you use? A link to the part would be good. 2) How are the relay coils wired up. 3) How are the relay contacts wired up to the magnets? 4) Are you doing anything to suppress the back EMF from the relay coils?
MAX7219 muxes at 800 Hz. Relays will chatter them selves to death pretty quickly.