Monitor - ISSN 1472-0221
The Newsletter for Data Acquisition and Control
Issue 267 February 2021
Hello and thank you for subscribing. This month we continue our smart city series.
You can download a pdf copy of this newsletter here.
MQTT is a simple messaging protocol, using very low bandwidth. It's the perfect solution for Internet-of-Things applications. MQTT makes it easy to establish communications between millions of devices and so is ideal for Smart City applications.
When a publisher in the Smart City - such as a pollution sensor - has new information to distribute, it sends a message with the data to the connected "broker" or server. The broker then distributes the information to any "clients" that have subscribed to that topic, such as an app showing today's levles of nitrogen dioxide and other pollutants.
Some terms used in MQTT
- MQTT Messages
- Information that devices exchange. Either commands or data.
- MQTT Topics
- A label attached to a message. Lets a device register interest for that type of message, or sets where it wants to send its message.
- MQTT Broker or Server
- Receives messages and publishes them to all clients subscribed to that topic. The terms server and broker are interchangeable for MQTT.
- MQTT Client
- Subscribes to a topic and receives information from the broker, for example an app running on a mobile phone showing people counts. A client may also publish messages to the broker, so a people counter could be a client.
- When a publisher, like a people counter or temperature sensor, sends information to the broker.
- When a client, like a reporting system, wants to get a specific type of information from the broker.
I am interested in a simple DAQ package. Purpose is to link Circutor energy power meters together with some China meters. Circutor meters have RS485 while the China ones have both TCP and RS485 outputs. Can this be done with your software? If so what are all the components needed?
You can download the free comDebug software from https://www.windmill.co.uk/serial.html and try for each meter type. This will allow you to read from either RS485 or tcp meters. If you can get the readings you want you can download the full Windmill package which will let you collect from multiple devices, using the files you have created in comDebug.
comDebug can take readings from all sorts of devices communicating over RS232, RS422, RS485, Modbus and TCP/IP.
Honeybees can solve maths tests without using numbers
The insight icould be used to design more sophisticated machines based on the brains of animals, which have evolved to find the simplest, most efficient way to carry out certain tasks.
Source: The University of Sheffield
New device measures fat burning in breath
Breath holds the key to monitoring fat burning, and a research group from in Japan has created a compact device that uses an ultraviolet lamp to gauge exhaled acetone gas, which is produced in the blood through the metabolic reaction of fat.
Source: Tohoku University
Soft sensor could map pressure points for amputees
A soft, flexible sensor system created with electrically conductive yarns could help map problematic pressure points in the socket of an amputee's prosthetic limb
Source: NC State University
Wearable device turns the body into a battery
Researchers in the US have developed a low-cost wearable device that transforms the human body into a biological battery.
Source: University of Colorado Boulder
Biosensors monitor plant well-being in real time
The information from the sensors may help agriculture to adapt production as the world faces climate change.
Source: Purdue University
Underwater glider could silently survey the seas
Autonomous underwater vehicles have become versatile tools for exploring the seas. But they can be disruptive to the environment - new design solve these problems.
Source: SCUBA News
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