Solenoid driver quick help...

Community PCB Design
1

Hey all,

I always get so nervous when I ask a question on a forum! :oops: Thanks in advance!

I’m trying to make my first PCB to control a solenoid with a MOSFET. I have the circuit working on a breadboard.

I already ordered a very small run of a previous version of this board but I screwed it up (left off a couple things and also messed up the schematic) which sucks.

So this time around I would really appreciate another set of eyes to see if I’m missing anything major or I’ve made any gross errors…

Some (potentially helpful) info:

• I’m using a single 24V power supply (solenoid is rated 24v) with a 5V regulator (currently labeled IC2) for the Arduino and sensors

• I’m also reading a SPDT switch and two 10k pots, connected via Molex

• The diode for the solenoid circuit is currently soldered to the wires on the solenoid assembly, so it isn’t necessary on this board (in case you noticed it was missing).

• I haven’t routed any traces yet because I understand it’s a lot better to learn how to do it manually.

I’ve attached a couple pictures from Eagle for reference; please let me know if I can provide you with any more info to “help you help me…”

Thank you!!!

2

Give the board a part name/number and a revision so you know which version you’re working with.

I like to see explicit nets for all connections with the possible exception of power and ground busses.

Where does A0, A1, D2, D3 go?

If you have nothing connected to D9 and there’s a load (solenoid) on the FET, you can burn it out by floating the gate in the linear region.

Don’t trust your incoming power: add a 10uF cap on the input to the power supply and at least pads/holes for a 0.1uF one on the output.

What is the total current used by everything on the 5V bus? Can the regulator handle that power with a 19V drop across it?

Have you printed out the artwork 1:1 scale and stuck parts into the paper to be sure there’s room for fingers to plug/unplug things, use the switch easily, etc?

3

A0, A1, D2 etc. are the names of the pins on the Arduino - I’m using a Pro Mini, and this board is meant to manage power distribution and connections to the sensors and pins, as well as controlling the MOSFET.

Thank you so much for the tips and questions - I really appreciate it!