I’ve been playing with some very cheap, but quite good power meters made by Eastron for a few years now, in particular their compact (single-DIN) single phase Modbus meters. They are great for cheap (non-commercial) energy monitoring applications. The SDM120M variant has Modbus over RS-485 support for convenient data acquisition and integration. These aren’t the […]
Murphy’s Technology Laws! I found on an old hard drive circa 2011 🙂 You can never tell which way the train went by looking at the track. Logic is a systematic method of coming to the wrong conclusion with confidence. Technology is dominated by those who manage what they do not understand. If builders built […]
I recently had a problem with a particular Raspberry Pi and was able to rescue some files. I thought I’d document this here in case it’s useful. When powered on, I got an endless output of “mmc0: fsm 1, hsts 1” scrolling on the screen. Not good! My limited understanding of this error is that […]
I recently wrote a bash script that automates a database backups to zipped files on a Raspberry Pi. I would then periodically SSH in and transfer the backup files. This was a simple temporarily and manual solution, but I wanted a way to automate sending these files to a remote backup. I use AWS quite […]
Recently I had the need to upgrade MySQL on a Raspberry Pi running the latest standard distribution version of Jessie. I needed to use the JSON data-type as a MySQL field. My Raspberry Pi (as of April 2017) was running MySQL 5.5.52, but I needed 5.7+ for the JSON data-type. Update MySQL I’m providing these […]
When I first began using the Raspberry Pi to run Java applications, Oracle had yet to release a Java virtual machine that utilised ARM hard floats (hardware accelerated floating-point math processing). This meant that the Oracle JVM had to do all of this arithmetic in software causing excessive CPU load and poor performance. It was […]
Sometimes it’s necessary to leave a publicly accessible SSH connection available on your Raspberry Pi. While a strong password is essential, a much more secure method for authentication is to use a public and private key system. This guide will take you through all of the steps to creating the keys, configuring the Raspberry Pi, […]
The month the IDC Process Control Conference will be held in Brisbane Australia. Rav (Rise Technology Solutions) and I will be giving a presentation about cloud technology. Here’s the blurb: How ‘Cloud’ Technology is Revolutionising Industrial Automation The ‘Cloud’ is the new hype word in technology. Of course there is a lot of marketing and […]
Recently I’ve been developing a lot of reporting applications in JavaScript and have collected a few helper functions that I use regularly for number formatting. Here’s a look at each function and how you can use it in your own projects. Rounding a number to a defined decimal precision Input: 1234.567 Output: 1234.6 (to one […]
When I began developing PHP I found the biggest stumbling block for me was learning the best practices and many nuances for greater performance, especially when querying a database. I found that I could smash out functional PHP for proof of concept purposes, but when it came to optimising my code for release and I […]