We describe our first efforts to develop a set of off-the-shelf hardware components that ordinary people could connect to build a simple but useful class of embedded systems. The class of systems, which we call monitor/control systems, is composed primarily of sensors - light, motion, sound, contact, and other types - and output devices - light-emitting diodes, beeping speakers, or even electric relays that control electric appliances like lamps. For example, one monitor/control system would detect if a house's garage door was open at night, and would blink an LED inside the house to alert the homeowner of this normally undesirable situation. Today, configuring even the most basic monitor/control system requires knowledge of electronics and programming. We seek to create a set of building blocks, which we call eBlocks, that would enable someone with no knowledge of electronics or programming to be able to build simple but useful monitor/control systems, We are creating eBlocks largely by incorporating intelligence into previously dumb sensors and output devices, and by developing a set of standards and methods that enable eBlocks to work together seamlessly when connected. eBlocks have only recently become possible due to the extremely low cost, low power, and small size of embedded microprocessors. We describe our first results of creating a basic class of eBlocks, Boolean eBlocks, that from a user's perspective transmit or receive only "yes" or "no" signals. We discuss the internal eBlock design, eBlock system design issues and decisions, and several eBlock-based systems designed by ourselves and by undergraduate students.
