Designing your own circuit boards can be daunting for a new maker, but your effort is quickly rewarded. Whether you're etching your own circuit boards or printing them on a plotter, the ability to create even simple single- and double-sided circuits lets you condense an unwieldy collection of breadboards and wires into something neat and pocketable - like Francisco Zamora-Martinez' AlarDuino.
The components in Francisco's AlarDuino, which is designed as a low-cost and customisable vehicle alarm, are simple: an accelerometer is used to detect sudden movement, which when triggered activates an external siren. Additional inputs in the form of a temperature sensor and a passive infra-red (PIR) sensor can detect vehicle occupancy, with all inputs adjustable for sensitivity using on-board potentiometers. A flashing LED provides visual feedback when the alarm is activated, and an on-board piezoelectric buzzer allows you to test the alarm without going deaf.
What would, in breadboard form, be a mess of jumper wires is instead a neat add-on shield compatible with any Uno form-factor Arduino or clone. The secret: Fritzing, a free circuit board design package built to be as accessible as possible. Fritzing allows the user to duplicate a breadboard design on-screen, turn it into a schematic, then lay out the components on a printed circuit board ready for home or professional production. The software even includes a small-run PCB production service accessible directly from its menus which, while far from the cheapest around, financially supports further development of Fritzing.
Designed within the Fritzing software and available for download under a Creative Commons licence, Francisco's AlarDuino is a great introduction to the software - and if you find yourself in need of a low-cost vehicle alarm powered from a 12V battery, a useful device in its own right.
It uses accelerometer, PIR and temperature sensor to detect breaks in the car environment. The shield activates an external 12V siren as the one shown in the pictures. This project design will be updated in its GitHub repository.