1. Interfacing External Sensors to Telosb Motes April 06,2005 Raghul Gunasekaran

2. Telosb Motes Low power consuming Capable of operating in large clusters 8MHz MSP430 with 10KB RAM 250 Kbps data rate IEEE 802.15.4 Compliant Operating in 2.4 to 2.483 GHz Virtual USB programming Serial UART communication Programmable Flash Memory 48K 1 MB external flash for data logging On board Sensors (Temperature, Humidity and Light Sensor)

3. Telosb Motes Open source operating System – TinyOS Programmed in NESC - a modular programming language - an extension to C Built in 12-bit ADC Supports 8 channels Capable of interfacing with external Sensors

4. Interfacing a Geophone to a Telosb Mote Geophone is an acoustic sensor Operates in the frequency range of 1 to 5 Hz – magnetic coil and spring arrangement. Plugged into the surface of the ground – since low frequency waves propagate for longer distances.

5. Exploratory Seismographs www.geometrics.com/SmartSeisCropped.jpg www.geometrics.com/SMARTPATTY.jpg Works using acoustic sensors, buy measuring wave velocities through different materials Few Applications Oil exploration Underground Imaging Mineral Exploration Landslide studies & Earthquakes

6. Implementation Issues Synchronization - triggered data collection (most important for the application discussed ) Compression of data - Data collected is stored in the flash memory - data sizes would be in the order of 10kB + header information. Example: 12 bit ADC (2 byte storage space in the memory) sampled for every 1ms (or 0.5ms) time interval for a period of 2 (or 3) seconds would result in a data size of 6KB) - Reduced data size results in energy saving over transmitting high data

7. Implementation Issues Routing – Store and Forward - since the motes have a fixed arrangement - no complex algorithm required - moreover the programming space on the mote needs to be small for we have enough space for data logging.

8. Thanks