The Sensors Over Ethernet Project

1
The Sensors Over Ethernet Project

• Group 14

Group Members Andrew Golden David
Spurling Joshua Kraan James Canon
Sponsor Redpoint Controls
2
Introduction

• There exists a need for an affordable
  interconnected network of remote sensors in
  modern factories today.

What creates this need?

• Larger Factories
• Interconnected Facilities
• Outdated Technologies

3
The Application

• A typical factory based application is as
  follows

4
The Application

• Remote monitoring of the sensors

5
The Goal

• The main goal of this project is to interface
  multiple sensors to an existing network without
  the aid of personal computers in a cost effective
  and reliable manner a goal which no current
  interconnected sensing networks have achieved.

6
The Problem
In order to achieve this goal, certain problems
must be addressed and resolved.

• Cost
• Reliability
• Scalability
• Interconnectablility
• Speed

7
Direct Comparison
8
The Solution

• Ethernet as an obvious solution.

• Cheap 0.07/ft
• Reliable Standards TCP/IP
• Scalable 300ft without repeaters
• Interconnectable Preexisting wired nets
• Fast 10mbps

9
Design Specifications
10
Basic Design

• Using Ethernet as the communication medium

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Ethernet Controller Duties

• The Ethernet Controller will be used to perform
  the following functions

• Packet reception and transmission
• Memory for packet storage
• Convert data from microprocessor into
  transmittable packet form.
• Convert packet from Ethernet into readable form
  for microprocessor

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Ethernet Controller

• CS8900
• Integrated Memory
• 4-KB of on chip memory.
• Eliminates the need for external memory.
• Integrated 10BASE-T Transceiver
• Easy connection to Ethernet.
• Reduce external circuits.
• Ethernet Frame Transmission and Reception
• Collision detection.
• Preamble generation and detection.
• CRC generation (Cyclic Redundancy Check).

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Microcontroller Duties

• The microcontroller will be used to perform the
  following functions

• Retrieve data from the sensor
• Format data into useable form
• Control Ethernet Controller
• Send data to Ethernet Controller
• Receive data from Ethernet Controller

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Microcontroller Comparison
15
Microcontroller Selection

• PIC 16F877
• Lowest price
• Smallest physical size
• Most bits for analog-to-digital conversion
• Most configurable operating speed
• Adequate program and data memory

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Microcontroller

• PIC 16F877
• Sensor Interface
• A-D converter for analog sensors.
• Digital input for digital sensors.
• Multiple Ports
• Port for 8-bit data transfers between
  microprocessor and Ethernet controller.
• Port for control of Ethernet controller.
• Accessing received packet data.
• Controlling packet transmission.
• Large Program memory
• Needed for data transmission protocol.

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MicrocontrollerProgramming
Assembly and C compilers available for
PIC Compiled C code creates excessive overhead
for required network functionality Assembly is
smallest and fastest. No currently existing PIC
assembly network code Custom ASM code required
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Level 0 Context Diagram

• The user connects to the node via some network
  application layer protocol. The node software
  then proceeds to return the data gathered from
  the sensor to the user.

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Level 0 Data Flow Diagram
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Level 0 Block Diagram
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Conclusion
In conclusion, the following design decisions
were made

• Analog Sensor Input
• Microcontroller PIC16F877
• Physical Network Connection Category 5 Ethernet
• Ethernet Controller CS8900

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Redpoint Controls

• David Cushing, President
• Chris Garman, CEO
• Jarod King, Vice President
• http//www.redpointcontrols.com