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 website.

Andrew Buchanan,
Tawa, NZ. ($50)