Automatic computer start

My computer at home is connected to an extension cord with a power switch. I turn off the power every time I go to sleep, I am going to work… I often just turn off the power supply of the computer at the back by switching the power source. This saves the resource and it paid off for me, all my previous computers are used by my brother, May's mom….

I dealt with that thing: I turn on the switch on the extension cord with my foot (or switch off the source) and I don't want to bend down to the button on the front of the computer anymore 🙂 It wouldn't happen automatically after turning on the main switch ?

I solved it as follows: I cut the cables to the front button and soldered a 47uF capacitor parallel to the button. The voltage on the contacts of the board is +5V, so any will do. This is how my extension cord switches on after switching on (or resource) automatically start the computer. It also works when fastened with the front button, but so that the discharge of the capacitor is not too dangerous to the capacitor by a direct short circuit, I soldered a discharge resistor of 330 ohms to the cable from the button in series, through which the capacitor is discharged when the front button on the computer is pressed. So the automatic start also works, also by pressing the button in the front (the capacitor is charged after the computer is turned on for the first time and is discharged either by turning off the main power switch after about 10-15 seconds. or by pressing the front button). I found the value of the capacitor by experiment, I started with 47nF, the board did not turn on, I used 220uF and the computer turned on, but after the BIOS it remained stat. So I started to reduce the capacity of the capacitor to the lowest when it started and did not stop. 22uF was already small, and at 47uF it continued nicely. He also stopped for the first time, but then it worked without problems, I'm guessing, that he needed the first “formatting” capacitor. It would be a good connection for computers as well, for which it is necessary, to automatically turn on after a power failure from the mains.

Radovan PROKOP