Arduino Starter Kit - Project 4 - Colour Mixing Lamp

Investigate the use using a tri-color led and three photoresistors

A lamp will be created that smoothly changes colors depending on external lighting conditions

Using a tri-color led and three photoresistors, a lamp will be created that smoothly changes colors depending on external lighting conditions.

The Arduino can’t vary the output voltage on its pins, it can only output 5V. Hence you’ll need to use a technique called Pulse Width Modulation (PWM) to fade LEDs. PWM rapidly turns the output pin high and low over a fixed period of time. The change happens faster than the human eye can see. It’s similar to the way movies work, quickly flashing a number of still images to create the illusion of motion

• The Arduino Uno has six pins set aside for PWM (digital pins 3,5, 6, 9, 10, and 11), they can be identified by the ~ next to their number on the board.
• Photoresistors are sensors that change their resistance depending on the amount of light that hits them, also known as photocells or light-dependent resistors.
• A project video is available and an Instructables tutorial

Building

Built it in AutoDesk and Fritzing. This is good practice in using those tools.

• Autodesk. The simulation worked as can be seen on YoutTube.

• Fritzing

• Found the covering of the photoresistors with the coloured strips a little too fiddly.
• My wire cutting is not that brilliant, look at the red wire!