Abhimanyu Sanghi (02/EC/05)

Ankur Verma (15/EC/05)

Ashish Bhandari (20/EC/05)

Kshitij Gupta (41/EC/05)

Mentors

Prof. Subrat Kar

Astt. Prof. S.P. Singh

A quick summaryA quick summary

This presentation discusses a Distributed Climate Control System (DCCS).

Motivation behind DCCSMotivation behind DCCS 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.

Thus, we propose to devise a system to control climate parameters.

What is Distributed Control Climate What is Distributed Control Climate System (DCCS) ?System (DCCS) ?

Slave Nodes measure parameters

Master logs and responds to changes

System Specifications

Cost of each node < Rs. 500. Choice of microcontrollers-> ARM / MSP430 /

AVR / PIC. Interfacing with temperature (LM35), humidity and

carbon dioxide sensors. Interfacing with fan, mister and memory card–

requires Serial Peripheral Interface and Analog to Digital Converter Channels.

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

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:

Choice of Components (Contd.)

1. CAN CONTROLLER :MCP2515, Microchip Technology2. CAN TRANSCEIVER :MCP2551, Microchip Technology3. TEMP. SENSOR :LM354. IC-MAX232, General Purpose Board, Resistors, Capacitors,

Switches, LEDs etc.

Total Expenditure per node ~ Rs. 500Total Expenditure per node ~ Rs. 500

Selection of Other Components:

Block Diagram of SystemBlock Diagram of System

SPI CAN SPI SPI

Working of SystemWorking of System

SPI CAN SPI

Working of SystemWorking of System

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

BLOCK DIAGRAM

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

LM35 temperature sensor is used in the initial prototype of the system.

The figures have been made using Eagle

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

Features of LM35

Output Voltage is proportional to Celsius Temperature.Outputs 10mv for each degree centigrade temperature.Requires no external calibration.Rated for full -55° to +150°C range.

Operates from 4 to 30 volts.

Suitable for remote applications. LM 35

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

ADC Registers

ADC Multiplexer Selection Register – ADMUX : For selecting the reference voltage and the input channel.

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

ADC Registers Cond….

ADC Control and Status Register A – ADCSRA : It has the status of ADC and is also use for controlling it.

The ADC Data Register – ADCL and ADCH : The final result of conversion is here.

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

USART Registers

UDR - USART Data Register : When we read it you will get the data stored in receive buffer and when we write data it goes into the transmitters buffer.

AVR USART registers

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

USART Registers Contd.

UCSRA - USART Control and status Register A : It is used to configure the USART and it also stores some status about the USART. There are two more of this kind the UCSRB and UCSRC. UBRRH and UBRRH : This is the USART Baud rate register, it is 16BIT wide so UBRRH is the High Byte and UBRRL is Low byte.

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

PORT settings of Hyper terminal

Interfacing Temperature Sensor Interfacing Temperature Sensor with ATMega16with ATMega16

The result was displayed on Hyper terminal on the computer and verified.

Introduction to Controller Area Network (CAN) Bus Standard allows

microcontrollers and devices to communicate with each other without a host computer.

Message based protocol Bit rates up to 1 Mbps

Introduction to CAN (contd.)

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

All devices read bus value while transmitting.

Protocol implements Physical Layer and Data Link Layer of OSI Model.

Requirements of a Node for CAN Communication

Host processor ATmega16 CAN Controller

MCP2515 CAN

Transceiver MCP2551

The Master Node - Schematic

The Slave Node - Schematic

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

Thus, SPI has: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: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: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

Code Snippets for CAN Device Code Snippets for CAN Device DriverDriver

Configuration of CAN ControllerConfiguration of CAN Controller

Resets the CAN Controller

How to transmit data bytes

Next Steps….Next Steps….

1.Communication between Master and Slave Node

2.Interfacing of Humidity and Carbon Dioxide Sensors

3.Implementation of Discrete PID Controller

4.Interfacing of Memory Card

SummarySummary Average cost of slave node is ~ Rs. 500. Interfacing temp. sensor with

microcontroller. Design and Development of Test board that

includes a master node and a slave node, interfaced with CAN controllers and transceivers.

Implementation of device driver for the CAN Controller

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.

ReferencesReferences

For more information refer:

[1] Application Note: AVR 221: Discrete PID Controller for 8-bit AVR microcontrollers

[2] Development Tool User’s Guide for eZ430-RF2500, TI[3] Datasheet: MSP430X16X, Texas Instruments.[4] Datasheet summary: AT90CAN32, Atmel Corporation.[5] Datasheet: ATmega16, Atmel Corporation.[6] David Porter, Steve Gilson, “Data Acquisition System With Controller Area

Network and SD Card”, Cornell Univ.