I've recently started a quest to try and convert all of the RepRap electronics to something that is Arduino compatible. I've made good leeway on the stepper driver, motor driver, and yesterday I started to tackle the TIP120 driver. I'm not sure if that is the best name for it, but essentially it is a PCB with 3 PWM inputs from an Arduino that are each run through their own TIP120's in order to drive various components (heater coils, fans, etc). The circuit seems pretty basic, and I followed some guides on the internet, such as Tom Igoe's stuff. I do have some questions however:
Would anyone mind looking over my design? Its in Eagle, and located at https://reprap.svn.sourceforge.net/svnroot/reprap/trunk/users/hoeken/freeduino-power-transistors/
Power and grounding. We generally use PC Power supplies to drive our electronics, and I've placed a standard molex disk drive power connector as the connector for power in. It provides 12v, 5v, and GND. How do I integrate this with Arduino? Do I connect the grounds together? Can I use the 5v from the PSU to drive Vcc levels? Should I connect the 5v from Arduino to this 5v? I really like the disk drive method because it allows me to simply plug the power supply directly into the board and I don't have to make any cables or whatnot.
what would be a better name for this? PWM Driver? Power Transistor Driver? I'm just not sure what to call it.
edit: oh yeah, i forgot to mention that this board is licensed GPL.