Powering Metro Mini with 12V?


#1

Going to be straightforward from the start, I have no experience with Arduino but my project requires low costs and Arduino functions fit my needs.

I’m using the Arduino (looking to be the Metro Mini) to control an Led Strip to Light up slowly beginning at a set time. A Potentiometer is used to set the wait time until the strip is activated. The problem is that the Strip is 12 Volts and the Metro Mini has a USB port that is 5 Volts. I have a DC Jack socket for a circuit board that I can use, however, is it smart to power the Metro Mini with 12V too if it is only controlling the brightness and when the LEDs turn on?


#2

It is safe to do provided you feed power in via the Vin pin and not the USB power port.
Power the METRO Mini with 6-16V polarity protected on the Vin pin, or plug the micro USB connector to any 5V USB source.


#3

Do you happen to know what other pins should be connected to the power on the board? The socket adapter has 3 pins, I can guess 2 are + and - with the extra being ground?


#4

Vin on the metro would be the +V and a ground pin for the -V. The USB connector will have a +5v, data + data -, and ground pins.
The DC barrel jack connector has a sort of switch in it. With no jack plugged in two of the pins are shorted together. That lets the device its connected too run from an onboard power source, like say batteries. Plug a jack in the connector and that connection is broken and the power source feeding it becomes the one you just plugged in. Just plug your power supply into the barrel connector and measure each pin with a voltmeter to figure out which one is V+ and which one is ground.
https://shop.pimoroni.com/products/dc-barrel-power-jack-connector
The center pin is usually +, and that I believe connects to the solder pin at the very back. The other two are the switch part and - . I’m thinking the one underneath in the middle will end up being your - / ground pin.


#5

Perfect! Thank you very much!