kreegur_test_system

Test rig software - browser based data logging

Overview

Purpose

General data logging and viewing (numeric values) from any source.

Architecture

• Data distribution and communication via MQTT broker
• Data viewing via page on web server
• Data logging via Python script

Hardware

• Currently implemented on a Raspberry Pi but other hardware could be used

Installation

• Must install mqtt broker such as Mosquitto. The system currently expects the mqtt broker to be installed on the same machine (same ip address)
  • MQTT broker must be configured for port 1883 and websockets on port 9001
• Tested with Apache server with php
• Place files in Apache public docs folder (/var/www/html)

Operation

• Start Python script python/processor.py to send processor heartbeat
• OPTIONAL - Start Python script python/simulatedData.py to generate simulated data
• OPTIONAL - Start Python script python/apiCarbonIntensity.py to retrieve data from a web api (in this case, UK carbon intensity)

Data display and logging

Publish data to the mqtt broker to display it and log it.

Topic

The topic should start with data/numeric/ followed by the channel description (no spaces in description). For example, for the outside temperature, the topic could be data/numeric/temperatureOutside_degC

Payload

The payload should be a numeric value such as -15.5 or 12340

Logging (processor) module

The logging module is meant to be implemented as a separate Python script. This script (not completed) performs the logging operations and broadcasts its status for display in the user interface

Log file location is currently hardcoded to directory /var/www/html/logging

Messages

Module heartbeat

The module should broadcast a heartbeat so that the user knows that the module is operational.

Topic

The topic broadcast is processor/heartbeat

Payload

The payload is a JSON string that indicates whether the processor is currently logging. For example: {"logging":true}

Logging start command

Topic

processor/logging

Payload

start

Logging stop command

Topic

processor/logging

Payload

stop