Arduino micro used to activate 12v solenoid, via optoisolator, using a 15v wall wart. The power supply is rated at 15v 700ma, but puts out up to 19.5v. I would like to use it to
trigger the solenoid via the opto, and also power the arduino, I don't want to use batteries. The solenoid would only be momentary bursts, when a button is pushed, and burst speed controled by a pot. I am not worried
about over voltage to the solenoid and would fire it by closing the circuit with the opto. What would be a good way to power the arduino, at about 6v from the same power supply? LM317 voltage regulator?
or just resistors of (guessing so far) about 20 ohm. I am stupid and don't follow equations well, and need directions spelled out fairly clearly. And I have never used a LM317.
My sketch is still being developed but it seems to work out quite well on a breadboard setup, using a USB connection. I will transfer to PCB and box it when I get this power issue figured out.
Thanks for any help.
Steve
The Arduino runs best on about 7V. Get a 7V linear regulator like the Rohm BA07CC0T. It can handle an input voltage up to 25V.
Use a nice N-Channel logic-level MOSFET to turn the solenoid power on an off. Maybe something like an ON Semi NTD4963N-1G.
Thanks John. I'll look into that.
Steve
John, I could not find the N-chanel MOSFET, nor the Rohm BA07CC0T local, so I ordered a few from Mouser. How do I wire it? Like I said, I am a real beginner. I have looked for wiring instructions, but can't find what I need.
I think after I have these two items configured, I will be done with projects for a long time, and will not bother you again. (I hope :D)
Thanks.
The load connects from +18V to the Drain pin of the MOSFET.
The Source pin of the MOSFET connects to Ground (both the - side of the 18V supply and the Arduino Ground).
The Gate of the MOSFET connects to the Arduino pin. I have been told that a resistor (roughly 200 Ohm) in that path will prevent the Gate of the MOSFET from drawing too much current from the Arduino when you turn it on (the Gate acts like a capacitor).
John, I was refering to the Rohm BA07CC0T for wiring instructions, to get the 7v to the arduino.
Is this what you were telling me?
Sorry to be such an pest. I really don't know what I don't know =(
And thanks for the help. I hope this will be the last.
Steve
Stevequad:
John, I was refering to the Rohm BA07CC0T for wiring instructions, to get the 7v to the arduino.
A linear regulator has three pins: In, Out, and Ground. Connect In to +18V, Out (7V) to the Arduino's Vin (or power jack center pin) and Ground to both the - side of the 18V supply and the Arduino ground (or power jack outer sleeve).
John, I got the Regulator and MOSFET in the mail yesterday. They work great. I have it all transfered to a PC board, and put in a project box. Now with a push of the button (wired remote) the LED flashes, and the valve pulses. When I get the camera set up I can adjust the timing for collision drops via the POT.
Thanks for your help. It is much appreciated.
Steve