Controlling the atmospheric turbulence, microPIC programming

Table of Contents

Introduction

Previous Work

Motivation

Literature review

Free Space Optical Communication

Advantages and Disadvantages of FSO

FSO System

Effects of Atmospheric Attenuation of FSO Communication

Performances of FSO Links

Aim and Objectives

1. Programming microPIC for temperature measurement

2. Programming microPIC for humidity measurement

3. Programming microPIC for pressure measurement

4. Programming microPIC for controlling PWM fan

5. Programming microPIC for controlling Thermistors

Temperature Sensors

Working of DS18B20 temperature sensor

Power supply for DS18B20

Memory of DS18B20

DS18B20 Sequence

Coding for PIC16F627A and DS18B20 in C language

Arduino Program for more than 1 DS18B20 temperature sensors

PCB and schematic diagram

Humidity Sensor

Working of SHT11

Communicating with SHT11 humidity sensor

Calculating relative humidity

Coding for PIC16F627A and SHT11 humidity sensor

Arduino Program for SHT11 sensor

PCB and schematic diagram for SHT11

Pressure Sensor

Working of MPX4115a pressure sensor

Calculating pressure

Coding for PIC16F627A and MPX4115a pressure sensor

Arduino Code for MPX4115a

PCB and Schematic Diagram for MPX4115a pressure sensor

Results and Discussion

Conclusion and Further Work

Project Goals and Scope

The primary aim of this project is to develop an embedded control system for an indoor atmospheric chamber designed to simulate environmental conditions for Free Space Optical (FSO) communication testing. The project focuses on the accurate regulation of atmospheric parameters, specifically temperature, pressure, and humidity, using dedicated sensors and microcontroller-based circuitry to manage PWM-controlled fans and thermistors.

• Implementation of microPIC (PIC16 series) control systems for environmental parameter monitoring.
• Integration of specialized sensors (DS18B20 for temperature, SHT11 for humidity, and MPX4115a for pressure).
• Development of PCB layouts and C/assembly language programming for sensor data acquisition and control.
• Interface development between microcontrollers and computing systems via RS-232/COM ports for real-time monitoring.

Excerpt from the Book

Summary of Chapters

Introduction: Outlines the research context at Northumbria University regarding FSO systems and the need for an upgraded indoor chamber to replicate environmental variables.

Literature review: Provides a theoretical foundation for FSO technology, discussing its operating principles, sensitivity to atmospheric conditions, and associated performance metrics.

Aim and Objectives: Defines the specific goals of controlling temperature, humidity, and pressure within the chamber using microPIC microcontrollers.

Temperature Sensors: Details the operational and programming requirements for the DS18B20 digital temperature sensor, including hardware implementation and communication protocols.

Humidity Sensor: Explains the interface requirements, command structures, and mathematical formulas for calculating relative humidity using the SHT11 sensor.

Pressure Sensor: Covers the functional characteristics of the MPX4115a analogue pressure sensor and its integration into the control system.

Results and Discussion: Analyzes the experimental progress, highlighting the transition to Arduino for successful data acquisition when challenges with microPIC implementation arose.

Conclusion and Further Work: Summarizes the project outcomes and provides a critical evaluation of the implementation difficulties encountered with the intended microPIC approach.

Keywords

Free Space Optical Communication, Atmospheric Turbulence, microPIC, PIC16, DS18B20, SHT11, MPX4115a, Humidity Sensor, Pressure Sensor, PWM Control, Embedded System, PCB Design, Wireless Communication, Data Acquisition, Microcontroller Programming.

Frequently Asked Questions

What is the core focus of this project?

The project focuses on creating a controlled environment within an indoor chamber to simulate atmospheric turbulence, which is critical for evaluating Free Space Optical (FSO) communication links.

Which microcontrollers are utilized in this work?

The project initially targets the PIC16 series microcontrollers, though Arduino platforms were subsequently utilized to achieve functional sensor data collection.

What is the primary objective regarding environmental control?

The goal is to precisely monitor and control ambient temperature, pressure, and humidity to accurately replicate real-world weather conditions such as fog and turbulence.

What scientific methodology is employed?

The methodology involves researching sensor data sheets, designing PCB layouts for sensor interfacing, implementing firmware in C/Assembly for data acquisition, and utilizing serial communication for system monitoring.

What components are covered in the technical chapters?

The book details the technical integration of DS18B20 temperature sensors, SHT11 humidity sensors, and MPX4115a pressure sensors, along with associated PCB schematics.

How is the performance of the communication system measured?

The work discusses performance parameters for FSO links, including Bit Error Ratio (BER), received power, and the impact of atmospheric attenuation.

Why was the transition from microPIC to Arduino necessary?

The author encountered communication challenges between the intended PIC microcontrollers and the sensors, necessitating a shift to the Arduino platform to successfully obtain valid measurements.

What are the specific temperature sensors used in the research?

The project utilizes the DS18B20, which is a one-wire bus digital temperature sensor capable of user-configurable resolution.

How is the atmospheric pressure calculated in the project?

Pressure is determined using the MPX4115a sensor, with calculations based on a transfer function that accounts for voltage output and temperature-based pressure errors.

What does the final report conclude about the project's progress?

The conclusion notes that while PCB designs were completed, programming for certain elements like fans and thermistors remained incomplete due to time constraints and technical hurdles during the microPIC implementation phase.