Hello guys, I'm planning to use Raspberry Pi board to drive 8 pcs of 6V solenoid.

The solenoid need not to be active in one go but 2 or 3 might need to be active at one time.

What would be the ideal connection for the DC supply?

Each solenoid has it's own 6V DC supply?

But ground will be common and connected to Raspberry Pi.

Thanks for any ideas.

 

You can just use one DC supply connected to all the solenoids.

What is the solenoid resistance or current draw?

 

You can just use one DC supply connected to all the solenoids.

What is the solenoid resistance or current draw?

Solenoid rating is 300mA. I'm not really sure of the current draw.

 

Are you sure you want to switch power to the solenoids on the high voltage side and tie all commons together? You can build simpler circuits if you switch low side (connect all solenoids directly to 6V positive leg, and switch the ground legs of each solenoid with MOSFETs.) Here are examples of each scenario - in both cases demonstrating two solenoids worth of control circuits, but numbers 3-6 will just be identical copies of the first two. It's not a huge difference, but you save one transistor and one resistor per solenoid channel by switching low side.

 

Hi ebeowulf17, so basically there will be no harm if there are separate DCs to supply the solenoid?

Yes I do have almost same circuit with yours except for the relay part.

Thanks.

 

Hi ebeowulf17, so basically there will be no harm if there are separate DCs to supply the solenoid?

Yes I do have almost same circuit with yours except for the relay part.

Thanks.

As long as the various DC supplies all share the same ground as the Raspberry Pi, you should be fine.

 

Thank you, ebeowulf17.

 

A very big problem will be the inductive voltage spike when the solenoids are switched off. The circuits in post#4 include protection against damage from the voltage spike, but other arrangements may not show it. Such an inductive voltage spike may damage the processor board if there is no protection provided.

 

The protection is a 1n4001 diode.