# Presentation: 076257

## Evaluating the Use of DUST Inc. BLUE Motes for a Distributed Sensor Network With Collective ComputationMaria E. Martinez1Collaborators: Jared S. Dreicer2, Sarah S. Giandoni1, Paul D. Johnson2, Robert J. Nemzek12NIS-3, 1NIS-4 Los Alamos National LaboratoryLA-UR-03-4853

_**INTRODUCTION**_

- DSN-CC, a Distributed Sensor Network with Collective Computation is a detection system that consists of a group of small, portable, low-power micro-processing sensor nodes.
- Using RF transmissions, these nodes share specific information about a source with neighboring nodes to collectively determine a solution to the detection scenario.
- Applications being investigated for this network include acoustic localization, seismic vehicle tracking (Giandoni, et al), and moving radioactive source detection.
- A node (as shown to the right of this caption) is a small circuit board containing a RF transceiver, an antenna, and a microprocessor, which is programmed to perform and communicate specific tasks.
- DUST Inc. BLUE Motes have been selected for use as nodes in a DSN-CC because they  fulfill  the DSN-CC basic requirements for use in a
- low cost ($200.00)
- low power operating capabilities
- programmable microprocessor for detection and collective analysis
- RF transceiver and antenna for communication with other Motes

- Reliability Tests of DUST Inc. BLUE Mote Transmissions

- This test measures the number of data-packets successfully delivered from the network to the Gateway.
- For this test the motes were placed at an elevation of 1.5m in a wooded area.
- The variability of this data suggests that successful transmissions is
- 	dependent on topography.
- Even at a range of 91.5m
- 	the reliability may be as
- 	high as 98%.

- Resends were noticed within the Reliability Test data-log .
- a Resend is an identical copy of a previously-sent data packet.
- The Resends are being investigated as
- a possible cause in the variance of the reliability data.
- an unnecessary power draw
- and bandwidth usage in the motes.
- The frequency of these Resends is
- 	prompting a closer look at the
- 	parameters and algorithms
- 	involved in the DUST Inc.
- 	HDK data.log-Software.

- Figure 1

- Figure 2

- The signal strength measurement saturates for signals greater than –50dBm, resulting in the plateau at distances less than 16m.

- In the Range Test of  Figure 1:
- The DUST Motes were elevated to a height of 1.5m from the ground in a wooded area. The signal strength between the DUST Motes and the Gateway was measured at each range.
- The scattering of data points is due to multiple measurements in areas where were trees were thick.
- in these areas the motes were arranged in slightly different positions for each measurement.
- these obstructions decrease signal strength by –10dBm.
- the line, “Range^ -2”, shows the trend of the data, but is not a fit to the data.

- In the Range Test of Figure 2:
- The DUST Motes were tested at a height of 1.5m and at ground level in an
- 	open area.
- Signal strength measurements were taken at each range.
- The signal strength decreases at a rate of (range)-2.
- The ground-level transmission range is shorter than the tripod-level transmission range.

- Range Test of  DUST Inc. BLUE Mote Transmissions