You could put the Arduino in deep sleep, if you wanted to and that LED will still blink. With a little work, you could probably adapt this idea to any number of circuits out of the 555 playbook ...

This doesn’t hold true to the newest generation of Arduino, as those board have replaced the FTDI chip with an ATmega8U2. That’s basically and ATmega8 with native USB handling… fancy.

Most end users should find a supported "Arduino Core" that includes Optiboot for their desired target, and install that. Many such cores are provided by the hardware vendor, and they'll include Board ...

This paper presents an experimental set-up that combines on-chip digital techniques with off-chip Arduino-based hardware to simplify the test of widely-programmable analog-to-digital converters. The ...

“Most powerful” Arduino ever has ARM Cortex-A8 chip, runs “full Linux” 3D printers, sensor networks, and advanced automation enabled by Arduino Tre.