coll. - Make: Ultimate Guide to 3D Printing

In this project, youll combine an Arduino micro-controller, a Ping ultrasonic sensor, and LEDs to build a circuit that senses distances as hot and cold. Then youll run 3 Arduino programs (called sketches) that use this hot/cold information in very different ways. Its an easy project that requires no soldering, so its perfect for beginners. And its a great way to learn how a single circuit in hardware can be made to perform all kinds of tricks in the software that runs on the microcontroller.

Sketch 1 measures distance from the sensor. When youre far away, the cold blue LED glows. As you move closer, the cold LED fades and the hot red LED turns up to full brightness!

Sketch 2 is a capture the Ping game. The cold blue LED glows, and every so often, the hot red LED flashes. When the red LED is on, quickly move your hand in front of the sensor. If youre fast enough, the red LED will flash. Got it! If youre too slow, the blue one will flash. Fail!

Sketch 3 is a simple hot/cold switch. The cold blue LED pulses slowly until the sensor detects an object then the blue LED turns off and the hot red one shines at full brightness. Use this switch to trigger effects such as alerting you when someone arrives, or waking your computer when you sit in front of it.

Keith Hammond, MAKE Projects Editor

ADVERTORIAL

Jumper the Arduino to the breadboard.

Connect the Ping ultrasonic sensor to power, ground, signal.

Add the super-bright LEDs and their resistors.

Upload the Arduino program to the microcontroller.

The LEDs glow to tell distance: blue = far (cold), red = near (hot)!

Experiment with more hot/cold Arduino programs.

Learn to use an Arduino to read a distance sensor and control super-bright LED lights, without any soldering!

Parts list:

USB cable, A to B

Super-bright Blue LED, 5mm, 30mA @3.5V

Super-bright Red LED, 5mm, 25mA @1.86V

Resistor, 56, 1/4W, for Blue LED

Resistor, 150, 1/4W, for Red LED

Breadboard Jumper Wires

Tools checklist:

Computer running Arduino software (free download from arduino.cc)

USB cable, A to B (not pictured)

For complete instructions and details on this project visit:

radioshackdiy.com/hot-cold-LEDs

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