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Getting Organised - Jira, Confluence and GitLab for a Home Workshop

If you are like me chances are you will have many projects (or experiments) going on at the same time and accumulate new ideas or things to research on a daily basis. In this post I describe the tools and systems I use to help me manage that process - all of them are free or very low cost and can be hosted on your home network if you don't like the idea of keeping work in progress on the public cloud. Every year over the Christmas break I tend to perform a cleanup of my internal infrastructure and this year was no different, as my setup has been working well for a number of years now it seemed…

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Ohms Law and Resistor Networks

This post describes how I use Python code to apply Ohms Law to a resistor network to help select optimum component values that don't exceed the operating limits of an IC. In order to determine if the idea I had for controlling a LM317 regulator with a digital potentiometer was workable I had to determine that the limits of the MC4261 digipot would not be exceeded. In this case that means no more than 2.5mA flowing through the digipot resistor and a voltage drop across the resistor of no more than 5V (the supply voltage of the chip). This meant applying Ohms law and calculating the voltage and…

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Design Idea: Software Controlled Regulator

This post describes the design of a software controlled voltage regulator. At this point I am still trying to determine if the design is feasible within the limits of the components I have available. I have been toying around with ideas for small software controlled modules I can use for circuit analysis and testing. As well as the normal measurement modules you would expect (voltage and current sensing for example) there are also some signal injection modules that would be useful. One of these is a software controlled voltage regulator which could be used to simulate a battery discharging or…

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UART Based Networking for Microcontrollers

This article describes a simple networking system that supports multiple slave devices connected to a single serial port on the host system. The microcontroller side only requires a UART and can be implemented with a minimal amount of code. Background Almost two years ago I designed and built a small multi purpose bench testing tool to help with fault finding my electronics projects. The goal was to make it easier to measure voltages and currents at multiple points in a circuit without a desk full of multimeters. I wound up with a workable unit (workable enough for me to use at least) but the…

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A CNC Engraver Platform - Part 1

I have been looking for a way to simplify the creation of PCBs with a fairly high degree of accuracy - my series of posts about using a laser diode from a DVD/RW drive was an experiment to see if I could use that to expose copper on a PCB by burning away a layer of paint applied to the board. Unfortunately it turns out they are not powerful enough for the task (although they are still useful for other things). I started looking at other options including purchasing a CNC router to perform the task by cutting the copper layer away directly. Unfortunately the price of a full CNC router ranges fr…

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