Sensing and Communication with LEDs
2008-11-13 15:19:37.543917+01 by
Dan Lyke
1 comments
Very Low-Cost Sensing and Communication Using Bidirectional LEDs. By using two pins to drive a LED and current limiting resistor, they can sense how much light the LED is sensing when the LED is off. This was initially used to adjust the LED brightness to ambient light levels:
Compare this to the cost of adding IrDA [7] (about $7) or Bluetooth [8]
(more than $10) to a product. Using even a simple mechanical connector can cost
several dollars because of the required level-shifting and electrostatic discharge
(ESD) protection circuitry. Using an existing LED for communication can also
save manufacturing costs because expensive plastic molds for the housing need
not be altered to accommodate a dedicated infrared transceiver, antenna or
physical connector.
Via Brainwagon.
[ related topics:
Wireless Embedded Devices
]
comments in ascending chronological order (reverse):
#Comment Re: made: 2008-11-13 16:19:00.206918+01 by:
meuon
This is how electric meters do 9600 baud serial communications using two LED's. It's very old school, efficient, cheap for low speed communications. The difference here is doing it with ONE LED. Which is pretty smart.
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