9V Battery Snap to DC Male Power Adapter, Compatible with Arduino Uno R3

Cut the USB cord: this adapter snaps onto a standard 9V (PP3) battery on one end and plugs into your board’s 2.1mm center-positive DC jack on the other. Your Arduino Uno R3, Mega or compatible board runs untethered - the onboard regulator takes care of the rest.

Keep a couple in your kit for demos, classroom sessions, robot test drives and anywhere a wall adapter can’t reach. The leads are long enough to tuck the battery neatly into your chassis or enclosure.

Note: 9V batteries suit light loads best - for motor-heavy builds, consider a battery holder pack with higher capacity.

Illustrative image: oomlout, CC BY-SA 2.0, via Wikimedia Commons