Voicebell: Programmable Doorbell

This article was originally published at MTSI. To read more of our case studies visit our website for Micro Technology Services, Inc.

Before the programmable doorbell, your average doorbell appeared to be a pretty simple machine. They had a switch, an annunciator, and a chime and perhaps a window for displaying a name card. There could be a dial manually set to identify an occupant’s expected return time, or a tiny lamp to illuminate the device.

A two-way switch powered the device. Then came musical chimes connected to a clock for annunciating the time and read-only memory stored with several tunes.

The problem is that doorbells often lacked enough power to do much more than the basics — typically from the electricity flowing between two wires typically found where the doorbell is. A client approached MTSI with an idea that was ahead of its time — a patented, programmable and low-cost doorbell including a control for connection in series with an existing push button in a residential circuit — that could do more with those existing cables.

Solution

For Voicebell (U.S. Patent #US-5210520-A) we utilized a digital record/playback circuit to record an audible announcement as digital signals. When a visitor pressed the doorbell, they’d hear a neighborly greeting from the occupant converted from analog signals spoken into a microphone, converted to digital, and stored in the integrated circuit memory.

The charming trick was in programming the device switches to cycle between the ring and audio playback without exceeding the power requirement — and miniaturizing the circuit board and installing the device in its weather-resistant housing.

This article was originally published at MTSI. To read more of our case studies visit our website for Micro Technology Services, Inc.