Fabrication of a Wireless Sensor Network for Extreme Environments

1
Fabrication of a Wireless Sensor Network for
Extreme Environments

• Faye Yuen
• EE 496/NASA Fellowship
• Design Review Presentation II
• Fall 2006

2
Project Overview

• Create a network of autonomous motes to collect
  data in extreme environments (i.e. the Arctic)
  that analog Mars.
• Meet NASA Goals and Objectives.
• Contribute to Dr. Chris McKays research.

3
Overall Block Diagram
4
Water Sensor

• Why it was chosen
• How it works
• How it will be powered
• How it will be connected to the mote
• How data will be collected and sent
• Tests

5
Water Sensor Why it was chosen

• Met needs detects presence of water
• Understandable technology
• Compatible with motes
• Reasonably priced
• RoHS compliant

6
Water Sensor How it Works
Water
No Water
Internal reflection of LED light to
photo-transistor
7
Water Sensor Power

• Sensor requires 5 V to 12
• (Note the JN5121 microcontroller requires 2.2V
  to 3.6V)

8
Water Sensor Connection to Mote

• Pin 34 (Analogue to Digital input) on the motes
  Expansion Connector
• Input Signal ADC1 (connects to microcontroller)

9
Water Sensor Data Collection

• FLASH memory holds the application program that
  the internal processor will run
• Memory can be programmed by writing code in Bash
  shell and using the JN5121 Flash Programmer
• Track Packets (data transmitted on positive or
  negative edge of clock)

Programming Code
10
Water Sensor Programming Code
PRIVATE void vAdcDataLogger(uint16
pau16DataBuffer, uint32 u32Length) int i /
configure Analogue Peripheral timings, interrupt
ref voltage / vAHI_ApConfigure( E_AHI_AP_REGU
LATOR_ENABLE, E_AHI_AP_INT_DISABLE, E_AHI_
AP_SAMPLE_2, E_AHI_AP_CLOCKDIV_500KHZ, E_A
HI_AP_INTREF) while(!bAHI_APRegulatorEnabled)
/ configure and enable DAC / vAHI_AdcEnable(E_A
HI_ADC_CONVERT_ENABLE, E_AHI_AP_INPUT_RANG
E_1, E_AHI_ADC_SRC_ADC_1) while(TRUE)
for(i0iltu32Lengthi) vAHI_AdcStartSample(
) / start capture / while(bAHI_AdcPoll())
/busy wait until capture complete
/ pau16DataBufferiu16AHI_AdcRead() /
store in buffer /
11
Water Sensor Tests

• Detects water?
• Accuracy?
• Reliability?
• Response to different water forms (ex. liquid,
  solid, gas)?
• How much of dome needs to be covered by water for
  it to indicate its presence?

12
Remaining Work

• Build (waiting for supplies)
• Test
• Casing
• Documentation REVISE 496 REPORT! ?

13
Timeline for Completion
Previous Gantt Chart (from Design Review I)
----- Completed -----
----- Completed -----
----- Completed -----
----- Completed -----
----- Waiting for Supplies -----
----- Today -----
----- Today -----
----- n/a -----
----- Waiting for Supplies -----
Revised Gantt Chart
14
Gantt Chart
15
Thank You!

• Any Questions?