How To Power An Arduino With A 9v Battery. I want to move the led half of the break beam to the far side of a doorway so it can be used to count foot traffic. Make your Arduino projects portable by using a battery for power.
Connect the black lead from the battery connector to one of the Arduinos ground pins and connect the lead from the toggle switch to Arduinos Vin pin. You can power it through the V-in pin. Make sure you have a code loaded on the bored and plug your 9v battery set up into the Arduino and see if it works.
Like already mentioned you need a minimum of 5V to power up an Arduino.
Is there a way to hook up the ir led to a 9V battery without using a breadboard. Duncan comments that this nearly doubles the quiescent power draw from 9V as well as the power needed for every mA of 5V since 49ths of the power gets wasted as heat by the voltage regulator. You should see the green light on the Arduino turn on to indicate that it is powered. Press J to jump to the feed.
