Microphone muting

[boatman]

I have a design for a microphone mute box and wondered if anyone is interested in using the schematic. The specification is as follows:

 

The PCB must fit into the standard Canford extruded case (see here).

There will be two LEDs, one red (MIC OPEN) and one green (MIC SAFE) and two buttons (MIC OFF & MIC ON).

The board will be battery operated from a PP3 (this will fit into a battery box like this on the front panel).

The LEDs must flash briefly at regular intervals to indicate that the battery voltage is low.

The box must be capable of being controlled from one or more remote positions connected through a multi-core cable.

The board must be capable of operating from an external 12V supply connected to any of the positions on the control loop.

 

The PCB is built and tested and works perfectly but, at the request of the client, is designed with screw terminals for the connection of the mic in/out loop and the remote control. If anyone is interested in having one of these I will be happy to redesign the PCB to fit one of the Farnell cases we are using for the Bluecom system together with front and back panels to suit. The redesigned board will have PCB mounted 3-pin XLR connectors and the remote control will utilise two RJ45 connectors for loop-through capability. As in the current design the same PCB will be used for both the main box and the remote control. The MIC ON button will be PCB mounted. I envisage that the MIC OFF button will be a large knob on the top of the case for easy access.

 

Some more information here:

 

Production version schematic.

 

Production version component placement.

 

Photo of prototype PCB.

 

http://mydesk.myzen.co.uk/_Useful/MuteBox/MuteBoxPcb_1_0.jpg