A Low Cost Distributed Climate Control System

A LOW-COST DISTRIBUTED CLIMATE CONTROL SYSTEM (DCCS)

Abhimanyu Sanghi (02/EC/05)

Ankur Verma (15/EC/05)

Ashish Bhandari (20/EC/05)

Kshitij Gupta (41/EC/05)

Mentors

Astt. Prof. S.P. Singh

Prof. Subrat Kar (I.I.T. Delhi)

A QUICK SUMMARY…

Introduction

Work Completed

Future Work

Conclusion

This presentation discusses Distributed Climate Control System (DCCS).

Introduction

Climate encompasses Temperature Humidity Atmospheric Gases e.g. CO2, CO …

Ideal climatic conditions and parameter values vary. Climate control essential for

Manufacturing, processing, packaging, transport or storage of various sensitive goods

To prevent damage, deterioration or contamination of sensitive goods.

Motivation behind DCCS

We propose to devise DCCS to control climate parameters!

WHAT IS DISTRIBUTED CLIMATE CONTROL SYSTEM (DCCS) ?

Slave Nodes measure

parameters

Master logs and responds to changes

Sensor Data/Feedback Decision

Block Diagram of Proposed System

Work Completed

• Cost of each node ~ Rs. 600• Selection of suitable microcontroller

ARM / MSP430 / AVR / PIC

• Interfacing sensors with microcontroller• Interfacing with CAN, fan and external memory

Requires SPI and TWI

• Choice of communication networks CAN / RF / RS485 / RS232

SYSTEM SPECIFICATIONS

CHOICE OF COMPONENTS

1. eZ430-RF2500 Development board.

2. MSP430F169.

3. AT90CAN32.

4. ATmega16.

ATmega16 is selected which meets system requirements

SELECTION OF MICROCONTROLLER

CHOICE OF COMPONENTS (CONTD.)

1. RS232.2. RS485.3. Zigbee.4. CAN.

CAN Network is selected for our system.

SELECTION OF COMMUNICATION NETWORK

1. CAN Controller MCP2515, Microchip Technology

2. CAN Transceiver MCP2551, Microchip Technology

3. Temperature Sensor LM35

4. Other Components : IC-MAX232, General Purpose Board, Resistors, Capacitors, Switches, LEDs etc.

Total Expenditure per node ~ Rs. 675

SELECTION OF OTHER COMPONENTS:

CHOICE OF COMPONENTS (CONTD.)

Cost Analysis

Block Diagram of DCCS

SPICANSPITWI

Working of DCCS

SPICANSPITWI

FAN

Working of DCCS

Ext. Peripherals

Temperature Sensor

External Memory

LCD

DC Motor

External Peripherals

Temperature sensor LM35

ADCMicrocontroller

Temperature Sensor(LM 35)

Block Diagram

LM35

External Peripherals

EEPROMExternal Peripherals

Mask lower 4-bitsSend to the LCD portSend enable signalMask higher 4-bitsSend to LCD portSend enable signal

Send data/command Using 4-bit Mode

LCD

Block Diagram

External Peripherals

DC MOTORMOTOR DRIVER

Microcontroller

DC MOTOR

Block Diagram

Motor

External Peripherals

MOTOR

SLAVEµC

MASTER µC

MEMORY (EEPROM)

LCD

Temperature sensor LM35

MASTER NODESLAVE NODE

Block Diagram highlighting External Peripherals

External Peripherals

CAN

CAN -- Controller Area Network

Bus Standard Allows microcontrollers and devices to

communicate with each other without a host computer

Message based protocol Event triggered Bit rates up to 1 Mbps

Introduction to CAN

CAN & OSI Model

Communication between two nodes over CAN

Features of CAN Communication

Data transmitted through dominant bits (0) and recessive bits (1)

All devices read bus value while transmitting

Collision avoidance via bitwise arbitration

Error detection via bit stuffing

Requirements of a CAN Node

• Host processor ATmega16 • CAN Controller MCP2515• CAN Transceiver

MCP2551

Interfacing at Master Node

Interfacing at Slave Nodes

Code Design

Device Driver for CAN ControllerFunctions to read from and write to the controller

Thus, SPI has:

4 interface pinsMOSI, MISO,SCK, SS or CS

3 registersSPDR data, SPSR status , SPSC control

Writing SPDR -> Initiates Data Transfer

All data movement is coordinated by SCK.

SPI Data Register (SPDR)

Thus, SPI has:

4 interface pinsMOSI, MISO,SCK, SS or CS

3 registersSPCR control , SPSR status , SPDR data

Interrupt flagSet when serial transfer is complete

SPI Status Register (SPSR)

Thus, SPI has:

4 interface pinsMOSI, MISO,SCK, SS or CS

3 registersSPCR control , SPSR status , SPDR data

Interrupt flagif set, interrupt occurs!

SPI Control Register (SPCR)

SPI enableif set, SPI interface enabled

Clock Polarity and RateIdle mode SCK and Rate

Configuration of CAN Controller

Resets the CAN Controller

How to transmit data bytes

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 1: INITIALIZATION

Receive Buffer Filters of Slave Nodes are set such that they receive onlycorresponding Master Node messages.

Reset

Filter Set

Filter Set

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 2: Wait…

Slave Nodes 1 and 2 waits for incoming trigger messages from MasterNode.

Ready

WaitWait

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 3: Node 1 Triggers

Master Node sends message intended for Slave Node 1 first and waits forits response.

Sending

Message

Msg. Rxd.

WaitTR

IGGER

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 4: Node 1 Sends Data

Slave Node 1 replies with data and again waits.

Master Node logs data in EEPROM

Node 1Data

Logged

Sending

Sensor Data

WaitSen

sor

Dat

a

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 5: Node 2 Triggers

Master Node sends message intended for Slave Node 2 and waits forits response.

Sending

Message

Wait

Msg. Rxd.

TRIG

GER

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 6: Node 2 Sends data

Slave Node 1 replies with data and again waits.

Master Node logs data in EEPROM

Node 2Data

Logged

WaitWait

Sensor

Data

DCCS AlgorithmMaster Node

CAN Bus

Slave Node 2

CAN Bus

Slave Node 1

CA

N

Bu

sTemp. Senso

rFAN

Temp. Senso

rFAN

Step 7: Process Repeats

Master node send trigger signal to Node 1 and process repeats…

Sending

Message

Msg. Rxd.

WaitTR

IGGER

Testing : Loopback

Integration

Basic CAN Communication

Interfacing Peripherals

Selection of Components

DCCS – Working Demo

Future Work

Future Work Characterization of temperature sensor Interfacing slave nodes with other climate

sensors and controllers Effect of increase in number of nodes on

efficiency of system Effect of increase in length of CAN Bus

Conclusions

Conclusions

• Average cost of slave node is ~ Rs. 700• Prototype includes one master node and two

slave nodes• External Peripherals (EEPROM, LCD, Sensors and

Motor) are interfaced• System Development and Extensive Debugging

was done

We propose the use of this system as either a stand-alone system in the industry or workplace

or as an integrated device with climate modifying appliances such as an air conditioner

or a heater

Thank you.