The ATX power supply is a good thing to use not only because they are cheap, easy to find and you can often get one from an old PC for free. But when using the RAMPS, if you hooked it up properly, the standby 5v(Usually Purple cable) will power the board and LCD even when the PSU is off. With the PS_ON(Green cable) hooked up, your power supply magically start at the beginning of a print, and shutdown at the end, leaving the electronics running.
I included a picture for those who don't know how, by the way, if you do that, don't forget to remove diode D1, there are two diode, the one you need to remove is the one under a pololu. After that you need to tell your firmware( i use Marlin) that it needs to power the PSU before the print, and stop it after. So in slic3r's printer settings(if you use slic3r), in custom G-code, add M80 at the Start, before G28, and M81, at the end, after M84. Save your defaults settings after that.
I use a power supply from an old Server, the 5V Standby is 2A on mine so, plenty of power, but most PSU have 500mA, which should be enough.
More Info on the Wiki I though that this info was hidden pretty well in there...
I thought about using a smaller PSU, and power the hotbed with an dimmable halogen lamp electronic transformer, it would be cool to adjust the voltage given to the heater instead of just on and off the relay, but then i thought, i still need the relay, can't power that bed all the time... And i already had that extra PSU... Maybe i'll try it on another build.
[attachment 28758 PS_ONSmall.jpg]
I included a picture for those who don't know how, by the way, if you do that, don't forget to remove diode D1, there are two diode, the one you need to remove is the one under a pololu. After that you need to tell your firmware( i use Marlin) that it needs to power the PSU before the print, and stop it after. So in slic3r's printer settings(if you use slic3r), in custom G-code, add M80 at the Start, before G28, and M81, at the end, after M84. Save your defaults settings after that.
I use a power supply from an old Server, the 5V Standby is 2A on mine so, plenty of power, but most PSU have 500mA, which should be enough.
More Info on the Wiki I though that this info was hidden pretty well in there...
I thought about using a smaller PSU, and power the hotbed with an dimmable halogen lamp electronic transformer, it would be cool to adjust the voltage given to the heater instead of just on and off the relay, but then i thought, i still need the relay, can't power that bed all the time... And i already had that extra PSU... Maybe i'll try it on another build.
[attachment 28758 PS_ONSmall.jpg]