There used to be a time when an intercom used to be merely a couple of bins with audio system joined through a few wires, with an audio amplifier someplace within the combine. However intercoms have like the whole thing else joined the virtual age, so the ones two wires now raise a load of different capability as virtual signalling. [Aaron Christophel] installs those units for a dwelling, and has posted a captivating opposite engineering video that we’ve additionally positioned underneath the ruin.
Energy for the machine is provide as a relentless 24V DC, and the audio continues to be an old school analogue sign that we’ll all be acquainted with. On that 24V DC although are imposed a sequence of pulse trains to cause the other alarms and different purposes, and he describes extracting those with an oscilloscope prior to appearing us the circuitry he’s used to ship and obtain pulses with an Arduino. The majority of the video is then dedicated to the device at the Arduino, which you’ll be able to additionally to find.
The end result is a fascinating primer for any person who fancies a bit of of serial detective paintings, even though they don’t have a intercom at hand.