Wireless Sensor Monitoring

Group Members:Daniel Eke (COMPE)

Brian Reilly (ECE)Steven Shih (ECE)

Sponsored by:

1.12-1.18

Outline

• Project Overview • Communication• Hardware• PCB Design• Firmware• User Interface • Block Diagram

Project Overview

Goal: To create a wireless communication network to monitor sensor data during the manufacturing process.

Specifications: • Low power consumption • Range of at least 50 ft. • Capable of working in electrically noisy environment• Multiple units need to communicate at the same time

CommunicationStandard Wi-Fi Bluetooth ZigBee

IEEE Spec... 802.15.3a 802.15.1 802.15.4

Frequency Band 2.4 GHz 2.4 GHz 2.4 GHz; 5 GHz

Max Signal Rate 54 Mb/s 1 Mb/s 250 kb/s

Nominal Range 100 m 10 m 10 - 20m

Channel Bandwidth

22 MHz 1 MHz 0.3/0.6 MHz, 2MHz

Communication

Modulation Schemes ZigBee uses:• Direct Sequence Spread Spectrum

• Bit stream of transmitted data is divided into smaller pieces that are allocated across a frequency channel across the spectrum.

• The transmission data signal is attached to a higher data bit sequence, which then increases the signal’s resistance to interference.

Communication

Offset Quadrature Phase Shift Keying• After the bit stream is split into odd and even, one bit stream is

made offset by 1 bit period with respect to the other.• The direct and shifted bit streams are then fed into the frequency

mixer.• Prevents phase transition from the origin, by allowing only one

bit to change between the transitions.

Hardware Requirements

What we need from our chip:•Single Chip Solution•Low power consumption•Zigbee and Z-Stack Mesh compatible•Adequate amount of pins

PCB Design

• For the end devices, we want to incorporate a circuit consisting of the CC2530 chip and sensor.

• Will incorporate CC2530EM board from development kit

Firmware

• Our microcontroller will be utilizing Z-Stack Mesh to communicate.• Z-Stack Mesh is provided by Texas Instruments for free and is IEEE

802.15.4 compliant. • Provides a library of functions to use in C for our wireless

communication • This library will allow us to easily transfer and receive data from

multiple sensors without giving up on speed or reliability. • Used CC2531 USB dongle to collect packets and communicate with

the computer.

Z-Stack Mesh Configuration

Coordinator

End Device

Router

End Device

End Device

End Device

● Every node can relay data within the network being either a source or destination.

● Capable of connecting up to 400 nodes

● Many-to-many or many-to-one application routing

IAR Workbench

• IDE used to program CC2530 chip. • Program coordinator & router separately.

• Had to overcome errors in compiling our code.

Coding Milestones

• Established communication between Coordinator and Router• Created simple code to turn on LED on Router device• Used a simulated data to act as sensor values and transmitted them

from Router to Coordinator.• Was unable to read analog input from external circuit, even after

configuring the analog to digital converter.

USB Dongle

• Retrieves data sent between router and coordinator• TI has own packet sniffing software to retrieve packets

• Broadcast over UDP port to be used by LabView

Block Diagram

Sensor MCU+

Transceiver

MCU+

Transceiver

USBDongle

Computer

Analog to Digital Converter Wireless Communication Packet Sniffer

QUESTIONS?