Powersupply for Arduino Nano

[rnollen]

Hi,

I have created my first project using a light lux sensor on an Arduino Nano. Now, at this stage it seems like this sensor only works when I take directly the power of my USB port of the computer and use this to provide my arduino nano with power.. In the end I want to use an external power supply for this sensor, so as far as I know an USB port on a computer is 5V; I have tried several different 5v power supplies, but these don't work for this sensor.
I think normally a 7 to 12 volt powersupply should be used, on my Uno it is simple because this one has a Powersupply connector..
Question is, how must provide my Arduino nano of external power and which powersupply should I use? Must I connect this to the Mini USB port? Or must I connect something somewhere else to provide the power?

Thanks for the replies!

[Dwalt]

@rnollen

From the arduino.cc website:
Power:
The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30/VIN), or 5V regulated external power supply (pin 27/5V). The power source is automatically selected to the highest voltage source.

If you can't find a 5V phone charger with a USB mini jack, you can feed the power to VIN/GND and it will run through the voltage regulator on the bottom of the board. Unfortunately, the 3v3 pin is fed from the FTDI chip and won't work to directly supply the radio. You will need to separately regulate the voltage down to 3.3V for the radio.

[rnollen]

Thanks for the reply. But how do I know if the external power supply is "regulated"?. Tried two 5v external powersupplies on the mini USB port and they don't work. One I use to charge my Gopro, the other one I used on a phone. There they work The arduino only works now using the power on the USB port while connected to my computer.

I think it is easier to buy an universal powersupply, more then 5v and connect this then to the vin/grnd pin. I am afraid I otherwise could have the same issue?

[mfalkvidd]

If you have a 5V Nano you should connect the phone charger to pin 27 (and GND to GND).

[rnollen]

Ok, but if the sensor is not working OK when using a 5v powersupply connected through Mini USB, would it be any different then when connecting it to pin 27? Is there a difference in that, is it then regulated? Otherwise I will cut my USB cable to connect it to pin 27

Thanks

[mfalkvidd]

Sorry, disregard my last post. Using a phone charger connected to the USB mini jack should work just fine.

[ToniA]

I used to work for Nokia (and later Microsoft), so I have quite a few phone chargers. I've successfully used those Nokia chargers with USB-A connector on the charger itself. I.e. I can plug any USB cable into it, like a USB-A to USB mini (compatible with Nano). But I bet just about any USB power supply would do.

[rnollen]

In my case; that is the problem. The sensor does not when I use a phone adaptor on my USB port? I build a light lux sensor and I get bad readings then. Sensor works correctly when connected to my laptop using USB.
I have tried a nokia phone charger; same result?

[m26872]

@ToniA
OT: Those old Nokia chargers with just a tranformer and rectifier diodes, are quite useful when building non-switched power supply and thus good nRF24L01+ performance. If you have any of those to spare I'm interested...