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--- volume_control [2009/01/06 20:43]
lbarbour created
+++ volume_control [2009/03/04 05:37] (current)
jonmash
@@ Line 1: / Line 1: @@
-====== Testing the Volume Control ======
+====== Testing the Existing Volume Control Circuit ======
-The transmitter to the TV uses a circuit that incorporates a 555 chip. The signal from the microcontroller is sent to the 555 chip, which outputs as carrier signal. By setting the input to the 555 chip as high, it was found that the chip outputs a carrier signal with a frequency of 27kHz. Setting the reset to low shut off the carrier signal.
+{{ :gallery:ir_sensor.jpg?150|IR Sensor}}
-We attempted to test the receiver circuit using the transmitting circuit. It appears that they use different frequencies, so this was not possible. Using the LED on the transmitting side and a signal generator, we transmitted a signal of
+The transmitter to the TV uses a circuit that incorporates a 555 timer chip. The signal from the microcontroller is sent to the 555 timer reset input. This controls the output of a 40 kHz signal to an infrared LED. It was found that the existing timer outputs a signal with a frequency of 27kHz -- this is not sufficient for controlling a television. A new, improved, circuit will have to be developed.
 It was concluded that it would be simpler to create a whole new circuit, with the transmitter and receiver on separate boards.
+====== Software Development ======
+  * [[IRDecode|Code to decode an IR signal using the SIRC protocol]]

volume_control.1231274613.txt.gz · Last modified: 2009/01/06 20:43 by lbarbour

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