Radio Blinkies

Introduction

What is a Radio Blinky?

A Radio Blinky is a small device made by Hack Manhattan (designed by Guan) which is paired with an identical blinky, and uses radio transmission to light up an LED light on the remote paired device upon a button press. Any code system you can think of can be used to send messages!

Components

Microcontroller

ATMEL AT XMEGA microcontroller

Nordic Radio Module

http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01P

This is the small black board hanging off the edge of the main green printed circuit board, and it handles the actual radio transmissions and reception part.

LEDs

LEDs produce light when a voltage is applied to them in the correct direction.

Buttons

Buttons complete a circuit and provide an interface to the device.

Resistors

The resistors limit the current that can flow through the LEDs, preventing them from being destroyed by too much current.

Capacitors

Most of the capacitors are used as bypass capacitors, to reduce noise.

Batteries

Two 1.5V AA batteries.

Codes for communication

Simple 'Handshake' Acknowledgement

An incoming signal is acknowledged with either the same signal or a prearranged response.

Morse Code / CW

Morse Code was invented in the 1830's, and was later used for sending telegraph messages and weather, shipping and military operations. It is now used by amateur (ham) radio operators to communicate, especially when signal strength is very weak over long distances.

Learn Morse Code in your browser.

Morse Code can be faster than SMS text messaging!

2.4 GHz Radio

Interference

Many devices share the 2.4 GHz region of the electromagnetic spectrum.

Why is 2.4 GHz used for so many devices?

Design

Electronics Schematic

Schematic:

PDF:

File:Radioblinkies-schematic.pdf

Code

Firmware Source Code for the Radio Blinky, written in C.