I'm confused, having read a little bit, maybe not enough...
Can I power an Arduino Mega with an external, regulated 5V power supply? Or do I need to power it with 7+V? If I can use my own 5V supply, where do I feed it to the Arduino?
Can I power an Arduino Mega with an external, regulated 5V power supply? Or do I need to power it with 7+V? If I can use my own 5V supply, where do I feed it to the Arduino?
Yes you can power an Arduino Mega with an external regulated +5vdc power source. However the Arduino design does not provide the 'perfect' connection for such a hook-up.
Most people just wire to the +5vdc Arduino power pin and ground pin on one of the 6 pin shield connectors. This does work but has a few disadvantages. First is it has no voltage polarity or fused current limit. Second, if powered up external, and then plugged into the PC via USB you are effectively wiring two different +5vdc voltage sources together with no isolation for the two voltge sources. Again it will work, it's just not the best engineered solution.
The way I would do it is just get a hold of a spare USB cable and hack off the PC end connector, locate and strip the two power wires (+5vdc & gnd) and connect that to your external regulated +5vdc power supply. That way you also get utilization of the on board 500ma thermofuse to protect the board. When you want to upload a new sketch you just unplug the external power supply's USB cable and plug in your PC's USB cable.
Good luck
Lefty
Thanks. That sounds like a good approach, maybe hard to get a real clean job, but will look at this.
Does the 6-pin shield connector (is this the ICSP port?) usually supply 5V to shields? Yet can still work as a 5V input?
Does the 6-pin shield connector (is this the ICSP port?) usually supply 5V to shields? Yet can still work as a 5V input?
No, not the ICSP port pin connector. The Arduino has two 6 pin shield connectors, one has the analog input pins, the other has +5vdc and ground power pins (along with some other pins, like ground, Vin, reset, etc.), this second 6 pin connector is where you could wire your external regulated +5vdc and ground connect. However as I already stated I think there is a better method using a spare USB cable.
Lefty
Got it, Thanks Lefty!
-Mark