Momentary push button + attiny85

Projects General Guidance
1

Hello.
I'm converting an old ATX PSU into a station and I wanted to use a momentary button + attiny85 + 2n2222 transistor to simulate an PC power circuit.
I'm quite new on this but I find it interesting for this project.

My question is if it's easy to do or i'm missing something?
I know my PSU have 5V on standby that I can use to energize the attiny and I guess I could use an transistor to connect the green wire to ground.
The perfect senario was a short press on / long press off
Any help or info or better alternative is welcome.

2

You should read a bit on PC PSU, like the minimal load required for stable voltages.

I don't understand what you want to achieve, what's that "green wire", and what you want to press.

3

Hello,

I know that the PSU have an "PS_ON"(Green wire) that must be connected to ground to turn on.
I know as well there is a "+5V standby power output"(Purple wire) that is constantly on as long as AC power is live.
The PSU in question is an SL-250TFX that i was told that will need a minimum load on +5V rail(More research needed).

I know as well that connecting "PS_ON" to "Ground" will power up the PSU and i can easily do this with a simple switch.
But my idea was to Use the "+5V standby"(Purple) to power the attiny85(Programmed with arduino as ISP) and use a transistor to use as switch to connect "PS_ON" to "Ground" to simulate a "Press-ON-Hold-OFF" switch.

my problem is that i'm not sure is this is the best way to do this, if there is an easier way to this or if the codding will be easy as well.

i'm sorry for my limited knowledge on this field and for my poor English :slight_smile:

Regards

4

I would use an optoisolator for this.


Push button connected to input pin on Arduino not shown.