Raspberry PI Distance Calculator

Table of Contents

• Introduction
• Components
  • Hardware Components
  • Software Components
• Circuit Diagram
• Getting Started
  • Prerequisites
  • Installation
• Usage
• Use case 1 - Connected furniture
• License
• Acknowledgements

Introduction

Raspberry PI distance calculator is a simple python project that can be used to measure distance between two points and forward the events to Splunk for further analysis.

It uses GPIO modules of Raspberry PI to trigger an ultrasonic sensor and calculate the difference between send and recieve timestamps.

Ultra Sonic Sensor

An ultrasonic sensor is an electronic device that measures the distance of a target object by emitting ultrasonic sound waves, and converts the reflected sound into an electrical signal.

In order to calculate the distance between the sensor and the object, the sensor measures the time it takes between the emission of the sound by the transmitter to its contact with the receiver.

The formula for this calculation is D = ½ T x C (where D is the distance, T is the time, and C is the speed of sound ~ 343 meters/second).

Following acronyms will be used from here onwards

• RPI = Raspberry PI
• GPIO = general-purpose input/output

Components

Hardware Components

1. Raspberry PI (3 & 4 tested)
2. HC-SR04 Ultrasonic Sensor
3. Resistor : 330Ω
4. Resistor : 470Ω

Software Components

• Python
• Splunk

Circuit Diagram

Connections from the sensor and components are as below.

For detailed information about the GPIO Pins and description, please check GPIO

• VCC -> Pin 2 of RPI
• GND -> Pin 6 of RPI
• TRIG -> Pin 12 of RPI
• ECHO -> Pin 18 of RPI through 330Ω Resistor
• 330Ω -> Pin 6 of RPI through 470Ω Resistor

Getting Started

Follow the steps to configure and start the project.

Prerequisites

RPI Distance Calculator uses Splunk HTTP Collector to send data data to Splunk and then to analyse and visualize data.

Follow the Splunk HEC Documentation to set up Splunk HTTP Event Collector.

If Splunk set up is not available , you may switch off Splunk connections by setting following configuration in config.ini

[ splunk ]
disable = True

Installation

1. Install Python3

2. Intall the dependencies

   pip3 install configparser
   pip3 install argparse
   pip3 install git+git://github.com/georgestarcher/Splunk-Class-httpevent.git
   

3. Clone or download the repo to raspberry PI

   git clone https://github.com/rcpnair/rpi_distance_calc.git
   

4. Configure config.ini

5. Run the distance.py Add execution permission to the file and run ./distance.py

Usage

Program uses config.ini configuration file to get all required parameters.

If any of the parameters are not available, it uses the default values

By default, it looks in the current working directory of the program for config.ini file

You may override it and supply config from other locations using _--config_ or _-c_ parametert from the command line.

./distance.py --config /path/to/config_file_in_ini_format/

Use case 1 - Connected furniture

Using the distance calculator, height of an adjustable table can be measured and send data to splunk for further analysis.

Sample Dashboards

License

Distributed under the MIT License. See LICENSE for more information.

Acknowledgements

Thanks to georgestarcher for an awesome and easy to use Python Class for Splunk HEC