Kill those adverts quickly with the Supermute
The Supermute is a TV remote that turns the TV on or off, mutes
the sound and varies the volume up or down, using only three buttons. The
mute/on/off button is an industrial emergency stop button which makes it easy to
kill pesky adverts.
The circuit comprises a Microchip PIC12F675 8-pin
microcontroller, FET Q1, infrared LED1, the emergency stop button and two small
pushbutton switches for the volume control. Holding the emergency stop button
down for a second or more alternatively turns the television on or off.
A quick slap of the emergency stop button with an open hand (or
closed fist!) or a prod with the foot mutes or un-mutes the TV. The pushbutton
switches raise or lower the volume.
It is set for a Sony TV which has a simple IR protocol – a
5-bit address to identify the device being controlled (TV, DVD player, VCR, etc)
and 7-bit commands. The carrier frequency is 40kHz. The PIC program uses the
SLEEP function to limit the off-state current to less than 1mA and is woken from
SLEEP with any change on input ports 1, 2 or 3.
You can determine the bit pattern by a web search or by
measurement with the device’s original remote, an IR detector on a breadboard
and an oscilloscope.
The emergency stop button is an industrial Allen Bradley unit.
Jaycar have a cheap latching button emergency stop (Jaycar SP-0786) that can be
converted easily to non-latching but it is not as robust. Jaycar also have a
number of large momentary contact pushbutton switches.
The software can be downloaded from the SILICON CHIP
Tawa, NZ. ($50)