Not exactly schematics, but [Duckman] has some Arduino pinout diagrams he made using ASCII-art. These could be useful when pasted into source code as comments, documenting the pinouts for your ...

You can also go the 9v battery route plugged into the on-board regulator of the Arduino but the low mAh rating of a 9v won’t allow your project to stay running for very long.

You can use any standard 9V battery to power the whole circuit, and the Push-ON (push ‘n’ hold) switch ... Panic Alarm Interface Circuit Schematic. Panic Alarm Arduino Connection Reference Diagram.

Build Your Own Arduino Voltmeter Circuit and Voltage Divider Which Can Measure Voltages From 0V to 30V, ... The Arduino board can be powered from a standard 9V battery pack, as usual. Parts Needed.

“The Arduino Nano is a small, complete, and breadboard-friendly board based on the ATmega328 (Arduino Nano 3.x). It has more or less the same functionality of the Arduino Duemilanove, but in a ...

In this circuit, a MOSFET protects a reverse-connected battery from excessive current. The MOSFET conducts only when the battery is correctly connected, which lets the battery charge or discharge. In ...