Iv'e attempted to connect an lcd module up to my home pc, fed from a 5v molex plug adapted to suit the situation. The backlight and default message appear on the lcd module when the PC is booting up, however once windows begins the lcd only recieves 1v and the backlight dies on me.
Im unsure if this is simply my power supplies fault, or have i chosen a bad source of power attempting to connect from the 5v line? Any tips on how to improve the situation would be greatly appreciated!
I run my LCD powered from the arduino which is fed from the USB connection. The backlight is the biggest drain and they only run a few tens of milliamps, the panel itself uses microwatts. As an alternative how about using the 12V connection on the Molex and feeding it through the arduino's regulator ? However if it has a default message, it may suggest it isn't a standard HD44780 compatible LCD. Mine only shows what I tell the arduino to put on it.
Good catch on the "default message", pluggy: that probably means that it has something like a serial or I2C "backpack". The LCD itself may well have an HD44780 on it, but that won't be accessible to the Arduino or other device connected to it.
And some LCDs have backlights like EL panels that suck hefty amounts of current.
I think the problem lies in the 'Power Saver' P/S. At present i'm simply running a connection to the lcd screen straight from the computer, the arduino i wish to use afterwards.
I was wondering if someone could offer me advice on how i might go about powering up this LCD, could i modify an old pc power supply without the power saving features or am i best of investing in another form of a 5v power supply?
It is a matter of tapping off the power at the right point. I suspect that the +5Vsb (stand by) will not be switched off when the power save features kick in so you could try tapping that. It often has a different coloured wire to the normal 5V.