I know you can plug 9-12 VDC into the plug but can you use only 5? I'm not sure of the onboard regulator will chop the 5 volts down.
basically i have a buck converter powering my UNO but i want to use the same converter to power other connected devices. My buc is set to around 8 volts, but my UNO i think is struggling to power all my connected devices. I'm thinking of lowering the buck converter down to 5 vdc so it can power everthing. My UNO is currently packed into an enclosure and I cant get to Vin easily--Hoping to use the plug i'm currently
With 5V, connect it to the 5V on the power header, or use a USB cable and bring 5V in thru the USB connector.
The barrel jack needs ~7.5V, Vin needs 6 to 6.5v.
Just to be clear I connect 5 VDC from my Buck converter to the 5 (and GND) on the Arduino (not the Vin)? I thought 5 was a power output from Arduino but didn't know you could put power into that pin. I guess internally it's all a 5 VDC rail.
See my attached diagram showing the proposed connection.
Robin2:
Your diagram shows both 7.5v and 5v on the same wires. Be sure not to exceed 5v on the 5v pin.
I have discovered that 4.5v from 3xAA batteries also works fine when connected to the 5v pin.
...R
Where people tend to get bitten is just as these battery things get used - stuck out somewhere in the environment where the temperature wanders around. At low temps, battery voltages drop and the oscillators also tend to get fussy at the ends of the temperature range. What works well on the bench in the house, will get flakey out in the greenhouse, well house or whatever.
