This project was inspired by my girlfriend, who asked me to build an intercom for our house. There are many ways to build an intercom; an example is batteries in series with 2 telephones, a key switch and an amplifier. I felt this was far too simple. I decided to build an intercom with an MCU which digitalizes a voice and then sends it serially and then regenerates the analog signal.
I equipped the microphone with an ACG to ensure that anyone in between 1 inch and 10 feet from the microphone will sound good. After that I send the analog signal to the A/D of my MCU which digitalizes the voice and sends it serially to the other intercom that you have previously set the "address" for. The digital signal is sent to an RS422 interface, which sends it to a RS422 hub, which then broadcasts the data to the other intercoms. The addressed intercom takes the data and regenerates the analog signal via a PWM and a simple analog filter. I found a really cool 3 Watt Amplifier which works at 12 volts with a pin to control the output volume.
- Simple power amplifier with volume control
- PWM generated D/A
- Sine wave generator for key sound and pre-tone
26 Comments to “Digital Room to Room Intercom”
All my source codes were taken from my personal projects.
Everything is for your information only. The C/C++ codes have been written
with ICCAVR. You can find the header and source CRT files by downloading their compiler.
All is for your information and everything is AS IS without any warranty of any kind. No other files are available and I don't make any modification for any body.
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