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Last-modified: 2012-04-23 () 20:38:49 (2834d)
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How to use?

Download the LED_Tile10.zip, and extract to ~/Arduino/libraries. Library of "LED_Tile" will be available in Arduino IDE (v1.0). Refer three sample projects in File->Examples->LED_Tile for usage. (Detailed descriptions of usage will appear soon.)

Select Arduino(ArduinoNano? w/328) from Tools->Boards. The sensitivity adjustment will be needed in operation.

The software and hardware design data in this page is opened on CreativeCommons Attribution-ShareAlike 3.0 Unported .



Locate pin 1 of dot matrix LED unit at lower left. X coordinates are x=0 (left) to x=7 (right). Y coordinates are y=0 (upper) to y=7 (lower).

Contents and operations of sample projects

  • draw: draws dots (without pattern inputs) on matrix LED using write() function.
  • adjust: measures the value of illumination (voltage of exposed LED), to decide the threshold value for judging each LED is exposed or not, which is used in set_threshold() function. ('mode' is set as 'draw' to turn on the exposed LED.)
  • toggle: similar to 'adjust' project, with 'mode' of 'toggle' to toggle LED's on/off by each expose in each LED.


Basically, the photo sensitivity of LED is very small, and the voltage change by light exposure in LED is very small, up to approximately 1V. In addition, the obtained voltages for the same exposure slightly change in each sampling, since the voltage is also severely effected by AC noise; you can observe it by using oscilloscope. The photo sensitivity of each LED may be also different in each column.

For practical operations, the thresholds should be decided by using the built hardware with light exposure.

  1. Download sample project 'adjust' to Arduino. The voltage value of each column, y=0 (upper edge) and maximum value in whole LEDs are displayed.
  2. Expose LED in each column, y=0, and write down the measured value.
  3. Set the threshold values by using set_threshold() function.

źեե: fileLED_Tile10.zip 168 [ܺ] fileCC_SA30.png 208 [ܺ]