I am planning on powering the Arduino from the RPi with USB. I'm actually doing that right now with a 2A wall wart powering the RPi and USB to the Arduino/RAMPS stack. Haven't run into any problems yet, but I don't have anything connected to the RAMPS...
I have an Edimax wifi dongle installed and the official Raspberry Pi Camera module, so the Pi itself is consuming a bit of power. Any idea how much current the Arduino Mega 2560 and RAMPS need? I'd like to connect to the network via ethernet cable rather than wifi eventually for additional bandwidth and to reduce power consumption on the Pi.
I pulled out the ATX PSU from an old desktop last night and checked it out. Label says it provides 2A to the 5V standby, so that is great. Multimeter reads 5V from purple wire when PSU is plugged in but not "on". Shorting the green wire to ground turns the PSU on and I got +12V from all yellow wires. 12V rail supplies 20A on this supply, if I remember correctly.
Unless I'm missing something I think this will work. Still uncertain on the D1 diode... When the 12V supply is on, the Arduino will be getting power from both the USB and from the RAMPS board, right? Is that okay?
I have an Edimax wifi dongle installed and the official Raspberry Pi Camera module, so the Pi itself is consuming a bit of power. Any idea how much current the Arduino Mega 2560 and RAMPS need? I'd like to connect to the network via ethernet cable rather than wifi eventually for additional bandwidth and to reduce power consumption on the Pi.
I pulled out the ATX PSU from an old desktop last night and checked it out. Label says it provides 2A to the 5V standby, so that is great. Multimeter reads 5V from purple wire when PSU is plugged in but not "on". Shorting the green wire to ground turns the PSU on and I got +12V from all yellow wires. 12V rail supplies 20A on this supply, if I remember correctly.
Unless I'm missing something I think this will work. Still uncertain on the D1 diode... When the 12V supply is on, the Arduino will be getting power from both the USB and from the RAMPS board, right? Is that okay?