Abstract
The General Purpose Alarm Device (GPAD) shines lights and makes loud noises to draw the attention of a human being to a problem. It provides a programmable, 80 character display to provide textual information. As an inexpensive modular annunciator, it is intended to decrease the cost of any system that requires complex monitoring and rapid human intervention. Fundamentally, it is designed to act as a peripheral to a controlling computer or microcontroller. The controller may communicate over a USB (COM) connection or a 5V SPI connection via an RJ12 cable. The GPAD is intended to be as general purpose as possible, so that it can be used to provide alarm functionality for many engineering and scientific projects, hobby machines, instruments, and various situations. The original driving use case is to provide medical alarm capability to the PolyVent open-source mechanical medical ventilator. The GPAD supports 5 alarm levels above "silent" of increasing urgency in terms of light, rhythm, and frequency. It has a mute button. It is based on the Arduino Uno Atmega328 design and is potentially extensible through headers and shields like an Uno. The GPAD includes a printed wiring assembly, firmware for the GPAD peripheral, a simple documented API and a 3D printable enclosure. The repo includes instructions for using a second GPAD as a controller as an example for programming.