Sample project

The goal of the project is to produce a prototype for a device that responds to light by displaying the intensity in the form of a bar graph of LEDs.

For this workshop, that's as far as we go: to produce the prototype on a breadboard. But that is only a part of a larger process.

Final form

Embeded Arduino

The Arduino board is part of the final product. This could be the best approach for an intallation or for a larger product. The Arduino board may be connected with a shield.

Different construction techniques for this are beyond the scope of this workshop.

Embeded AVR Chip

The final product may be a printed circuit with a processor in the AVR family, loaded with software that was first developed using the Arduino board.


The computer runs the Arduino Interactive Development Environment(IDE). It can be Windows, Linux or Mac. The IDE is used to load the program onto the Arduino. The program on the Arduino can communicate through the USB cable to the computer. There is a window in the IDE with a terinal interface to display diagnostic messages and send control messages to the sketch while it is running.

Breadboard and Arduino Pins

The Arduino, in turn, is connected to devices through its I/O pins. The board has headers mounted on it so that each pin may be connected to the breadboard with a piece of 22 guage wire. Pins can be configured in the sketch to work as digital input or output. Some can be used as analog input.

In this project, we use pins pins 8 through 13 as digital outputs to drive the LEDs. Pins A0 and A1 are used as analog inputs, connected to the potentiometer and to the photoresistor.


Once the circuit is working and a sketch has been developed to control it, the computer is no longer needed. The Arduino can be connected to a power supply.