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A lightweight communication protocol to send data from your computer/phone to an embedded device by flashing the screen
C++ JavaScript Java
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Latest commit 66b9bc8 Sep 25, 2011 Joe Walnes Added receiver library for Arduino


FlashPrance is a toolkit allowing data to be transferred by flashing lights on and off.


It's primary purpose is to allow settings to be sent from a computer or cellphone to an embedded device, such as an Arduino.

The screen of the computer or cellphone will quickly flash between black and white at different intervals, and the device shall measure the duration of the light intervals to decode the data.

Because bandwidth is limited by the frames per second that can be displayed on screen, it is only suitable for very small amounts of data. It takes roughly 1 second to transfer 1 byte.

It's benefit is the cost and convenience. The sender (computer or cellphone) does not need any additional hardware or drivers - only the capability to flash an area of the screen - this may even be a web page. The only additional components on the receiver (embedded circuite) are a light sensor and a resistor - this should cost less than $1.

Planned Features

This is still an early work in progress - most of these features are not implemented yet.

Sender implementation libraries:

  • Web: JavaScript (DONE)
  • iOS: Objective-C (TODO)
  • Android: Java (TODO)
  • Terminal console: NCurses/ANSI (TODO)
  • Generic C++: algorithm + {MFC,GTK,QT,WinForms,...} (TODO)
  • Generic Java: algorithm + {Swing,SWT} (TODO)

Receiver implementation libraries:

  • Arduino (DONE)
  • Generic C: {atmega,attiny,msp430,arm,pic,...} (TODO)

Communication protocol:

  • Data streaming (DONE)
  • Clock syncronization (DONE)
  • Manchester encoding (TODO)
  • 8B/10B encoding (TODO)
  • Message framing: start/length/end (TODO)
  • Checksums (TODO)
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