Low-power wireless sensor with SNAP and IEEE 1451 protocol

The availability of low power short range RF transmitters and transceivers in the unlicensed band have made small low-cost, battery operated wireless sensors relatively easy to implement, particularly those employing microcontrollers with sleep modes. To extend access to a wider area, even nationally, and to a variety of sensor requires a standardized sensor network. We believe that the NIST-supported IEEE 1451 smart transducer standard is best suited for this role and in particular the IEEE 1451.5 version (wireless) which was developed for this purpose. However, while the Dot 5 protocol (or Dot 0) works well for moderate to high power devices, it is too verbose for the many low-power wireless sensors because the message size is relatively large, albeit much less than a typical Internet (TCP/IP) message. To reduce the message size, and thus improve the battery life, we employ the SNAP (Scaleable Node Addressable Protocol) format for data and the more concept Dot 4 (IEEE 1451.4) TEDS rather than the Dot 5/Dot 0 protocol. Conversion to the full Dot 0 format is done by the receiver or gateway before transmission on the Internet.