While the shapes, colors and sizes of the earliest Arduinos may have varied, one thing has remained the same: Atmel at its heart.
During Memorial Day weekend, the first Arduino to be made in the U.S. was hand built by Limor Fried alongside Massimo Banzi in Adafruit’s New York City headquarters. The initial board off the production line — which seems appropriate to have been an Uno (meaning “one” in Italian) — comes just a few days after Banzi’s announcement at Maker Faire Bay Area of the company’s manufacturing partnership with Adafruit, the availability of the highly-anticipated Zero, as well as the launch of its new sister brand Genuino.
With the theme of “firsts” in mind, we couldn’t help but reflect upon the earlier years of Arduino and some of its prototypes. And upon conducting some research, we stumbled upon a photo album showcasing many of them. While their sizes, colors and shapes may have varied, one thing remained constant: they all had an Atmel chip at its heart. (As you can see, many of which powered by an ATmega8-16PU.)
So without further ado, let’s take a trip down memory lane.
Arduino Prototype 0

At the time, the board was called “Programma 2005” as an evolution of the “Programma 2003.” (Source: M. Banzi)
Arduino Extreme v1
Arduino Bluetooth Prototype

The first prototype of the Arduino Bluetooth unit. The module was never easy enough to use for beginner Makers, and as a result, only a couple were ever manufactured. (Source: M. Banzi)
Custom Arduino Board – Lamp Controller

This custom Arduino features an iPod-like wheel sensor, an SMD Arduino, on-board RGB LEDs and three DSI outputs. (Source: M. Banzi)
Arduino Prototype 1

There it is: The first useable prototype ever created. As you can see, back then it was called “Wiring Lite” and used as a low-cost module for wiring users. (Source: M. Banzi)
Arduino Extreme v2
Arduino Ethernet Prototype
Arduino Bluetooth Proto 4
Arduino NG

Revision C of the Arduino NG did not have a built-in LED on pin 13. Instead, it featured two small unused solder pads near the labels “GND” and “13.” (Source: M. Banzi)
Arduino Ethernet and PoE Prototype

In the album, this board was labeled “Secret Prototype.” Not longer after, Massimo would go on to spill the beans in its comment section. (Source: M. Banzi)
Arduino Zero

The Zero boasts an Atmel | SMART SAM D21 ARM Cortex-M0+ core, enabling the board to run much faster and pack more of a punch than its 8-bit counterparts.
Want more? You can browse through the entire photo album here.