Big Blue Clear-Com Call Light

Rather than flashing every time a station presses their CALL button, this light only comes on when a CALL button has been pressed four times quickly. It starts out solid, then after a while starts blinking.

Perfect for getting a specific person's attention and ONLY when you need that specific person. I use this for the conductor in the orchestra pit. They just can't see the little call light on their intercom station.

This project uses a couple of modules and minimal soldering.

The first item is a step-down power converter. Rather than using batteries, let's power the unit off of the Clear-Com 30VDC line voltage. However, the components need 5VDC. An article about efficient power conversion led me to select the LM2596 which is available from Amazon.

The next item is an Arduino Nano. Be sure to order it from an authorized dealer such as Newark Electronics. The one I purchased from Amazon turned out to be a fake and would not work with the Arduino USB driver.

Deriving the CALL signal from the Clear-Com line was done by cheating. I simply purchased a Com-Bit from Illumineering and placed it in the enclosure, aimed at a photodiode. The photodiode is connected to one of the Arduino analog inputs which is held to ground with a resistor.

Then I selected and ordered a large blue illuminated pushbutton from Amazon. I changed the voltage drop resistor to work with the lower 5VDC used by the Arduino.

After a bit of Arduino programming I had a working call light. The light can be turned off by either pressing any CALL button once or by pressing the big button.