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More than Circuit EngineeringKeyboard with Contactless Buttons
Схемы >> Projects >> Keyboard with Contactless ButtonsKeyboard with Contactless Buttons
The keyboard with contactless buttons is based on the phenomenon of reflecting infrared rays. When the button is pressed, the infrared rays from the transmitter Тх gets to the receiver Rx. The source of infrared rays is LED (light-emitting diode), and the receiver of infrared rays is photodiode. The LEDs and photodiodes are located between a pair of metal plates at an angle of 90 °. A signal from the receivers is amplifying and decoding (fig.2).
Fig. 1. Keyboard
with Contactless Buttons.
Fig. 2.
The preference of Keyboard with Contactless Buttons is reliability, small size (thickness of the channel is negligible), resistance to the aggressive environment (pH, salinity, humidity, high temperature differentials).
O. Kapral
added 23.07.07 19:22:02 | 
looked over 8068 times
