The Arduino, Bluetooth module (check your specs, some HC-05, and HC-06 may come on a breakout board expecting 5V), and USB Host shield all run off of 3.3V, but devices you want to plug into the ...

For those written in the last week, our most popular stories on the site cover Arduino announcing a single-pair Ethernet adapter board for its Uno R4, warnings from the Electronica CEOs Forum, ...

You have to pull an extra wire from the sensor’s input voltage to your Arduino’s AREF pin, so you know what the actual voltage at the end of the cable is, so you can estimate the 10-90% range.