So I'm attempting my first Arduino project.
The setup is working 100% ... when powered via USB from my laptop. When plugged in via USB, I took a measurement of the 5v pin on the arduino and got 4.9 volts...HOWEVER, when I use my external power source, I can only get 3.9 volts on the 5 volt rail and that doesn't give me enough juice to kick over the relay in my project...
My external power source setup: I'm using a 12 volt battery. To keep heat down, I have a 5v switching voltage regulator (Mini DC/DC Step-Down (Buck) Converter - 5V @ 1A output [TSR12450] : ID 1065 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits). I have verified (with multimeter) that it puts out 5v. I'm plugging it into the VIN pin...
Since I'm already regulating the voltage, should I just plug the voltage straight into the 5v pin? Will that power the Arduino? Just want to make sure I don't start plugging things in and frying them...
For anyone interested:
It's a fan controller on for the electric fan on my truck. I'm reading resistance from a thermistor and when it reaches a certain calculated temperature, it powers on a relay that then powers a fan.
Thanks in advance!