Hi, can I use Sparkfun's 5v wall adapter power supply (Wall Adapter Power Supply - 5VDC, 2A (Barrel Jack) - TOL-15312 - SparkFun Electronics) connected straight to the 5v input of an Arduino Diecimilia/Duemilanove, or do I still need a voltage regulator between the two? If so, which one? It seems like most regulators with 5v output require a minimum of 7v input.
Thanks,
Bryan
Yes, you can directly put the power from that adapter to VIN and GND pins.
Thanks AdderD.
Has anyone actually done this? I'm wondering if I need filtering capacitors or anything to clean and smooth the power coming out of the adapter, or if it really is just as clean as the power coming out of the regulator on the Arduino.
A regulated wall adapter is pretty well regulated. The switchmode converter does an excellent job of regulating the outgoing voltage. The VIN pin on the arduino board runs through the filter cap on the board just the same as the onboard voltage regulator.
And, I have powered an arduino through the VIN pin with a regulated custom made power board and it works fine.
Well I'm not sure it will work well wiring into the Vin plug or pin. It's a regulated 5vdc wall wart, but after the reverse protection diode you will be at 4.5 or so and the on board regulator wants 7.5vdc so your kind of 3 volts shy.
Now wiring it to a 5vdc pin should work but I always worried about the on board regulator having voltage on it's output via the external voltage source, but no voltage on it's input, not sure that is good for the device? Does anyone wire 5vdc externally to the Arduino 5vdc pins?
Lefty
Usually, one provides 6.5V or higher to the VIN pin, and use the VCC pin as a source of power for devices. But it is perfectly fine to provide a clean +5VDC to the VCC header pin of the Arduino, and leave the VIN pin empty.
Huh... Worked fine for me... I just checked the schematic and it doesn't appear that VIN runs through the diode so it seems like it should be OK. Maybe I'm wrong though...
UPDATE: Ok, I checked the schematic and VIN is connected after the diode but still into VIN on the voltage reg so what I said was wrong. I do stand corrected. Sorry!
Thanks for your help everyone, it's much appreciated.