r/arduino • u/Grand-Ad7769 • 7d ago

Need Help on Multiplexed Circuit

I'm building a circuit to drive an 8×8 grid of 64 solenoids, where each solenoid needs to be individually controllable in both polarities (forward current, reverse current, or off).

My current plan is to use a multiplexed H-bridge matrix — 8 H-bridges driving the rows and 8 driving the columns — controlled by an Arduino. I'm planning to use 8 L293D ICs (each has 2 H-bridges, so 8 chips gives me the 16 I need).

My questions are:

  1. Will this approach work as intended?
  2. Are there any issues with using the L293D for this?
  3. Is there a better way to do this overall?
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u/Fess_ter_Geek 6d ago

I would consider using four MCP23017 chips for 64 extra digital pins. They work over i2c and you can chain 8 of them together. More if you use an i2c multiplexer chip with them.

Each MCP23017 chip will add 16 pins.

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u/Grand-Ad7769 6d ago

would this allow for current direction to be swapped?

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u/Fess_ter_Geek 6d ago

I think I misunderstood your plan... I thought you needed 64 pins to signal on or off to a solenoid board and were going to use arduino pins in a matrix.