I was intrigued by a recent project I saw that used two LED matrices placed diagonally to create an hourglass. The animated movement of the LEDs seemed a good simulation of the sand particles moving through the hourglass. As is common, the project emphasized on how the hardware was wired together, which is trivial, without much explanation of its more challenging/interesting software aspects. Additionally, most of the solutions I saw used an inertial position sensor to determine the position of the matrix, which seemed overkill for the simple functionality required. So I decided to explore th ..read more

Like many hobby woodworkers my wood shop doubles up as the garage which, limiting the amount of permanent ‘installation’ for equipment. This includes dust collection, and for many years I have been working with a single generic workshop vacuum moved between each source machine’s dust port. Over many years the number of tools I own has multiplied and most of them seem to have uniquely sized dust ports. Recently I reached a point where I had enough and decided to tame this Vacuum Hose Hell (VHH) of adapters and connectors that made it all work and decided to do something about it. Workshop Vacu ..read more

In the first part we looked at the HX711 hardware for implementing weigh scales systems. This part will cover how software interacts with the hardware, requirements for a library and how to write a weigh scale application. All the code described in this article can be found in my libraries code repository as the MD_HX711 library and examples. Requirements The most basic components of weighing machines a weight sensor, processing device and an interface (for example, these could be a load cell/HX711, a microprocessor and a display, respectively). They usually also have a method for taring the ..read more

If you search for ‘Arduino’ and ‘weighing’ you very quickly come across the HX711 board module and an associated world of strain gauges and load cells. All this looked interesting with some learning along the way. The result is that I took a dive into the subject and ended up with some new knowledge and ideas for the future. In this first part I cover the hardware requirements and in the next how to write software to implement a weighing system. The HX711 ADC The HX711 is a precision 24-bit Analog to Digital Converter (ADC) designed for weigh scales and industrial control applications. It re ..read more

A thread burner is a tool used to cut and melt the end of polymer-based threads (polyester, nylon, etc.) and paracords. By applying a very targeted application of heat, thread burners efficiently melt the last little bit of thread sticking out after the thread is clipped. They are also used to melt the knotted ends of threads to prevent the knot from loosening or untying. For some time, I have been using a commercial thread burner to seal my leatherwork stitching but have become increasingly irritated by the large number of AA batteries it consumes. There has to be a better way to do this, so ..read more

I fell into an internet search rabbit hole and came across ‘Drag Racing’ start lights. I had seen references to these on the Arduino forum and they looked interesting enough, and followed well defined rules, to be a relatively simple project for programming practice. Here’s the result from an afternoon of tinkering. The code for this project is available at my code repository. How do these start lights work? Drag races are started electronically by a system known as a Christmas tree. A common Christmas tree consists of a column of seven lights for each driver or lane, as well as a set of ligh ..read more

Rock/Paper/Scissors (RPS) is a game using simple rules and a circular winning strategy that I thought would be interesting to code. Additionally, there is an element of suspense/anticipation to the game that adds to its enjoyment, and I challenged myself with trying to capture this part of the experience as well. So, during a few of the many recent rainy days I decided to spend some time seeing what I could do with an Arduino Uno, some tact switches and a few LED matrix modules. All the code and supporting materials are available as the MD_MAX72xx_RPS_Game example of the MD_MAX72xx library. R ..read more

While researching how to detect a laser beam configured as a tripwire I came across a number of ‘recommended’ ways to do this. I decided to test the two cheapest viable options – an LDR and LED – to see which would best suit my needs. The sensor requirements for this application are relatively simple – detect a low power red laser beam interrupted by something passing through the it. The sensor needs to provide a reliable on/off signal within a few milliseconds of the event. It should also be inexpensive and implementable with a minimum of supporting passive components (ie, no op-amps, transi ..read more

Analog panel meters (APM) are instruments that measure and display variables on a dial, usually with a moving pointer or needle in front of a proportional scale. I wanted to try using these meters in a clock project but have been put off by their high unit cost. However, a recent ‘fire sale’ at a local electronics wholesaler provided the opportunity to acquire 10 meters for just a few cents each, so this project became feasible. All the files and software for this project are available online at my code repository. The concept for this clock is to display the clock’s date and time elements o ..read more

I have a few DS3231 Real Time Clock (RTC) modules with battery backup where the battery has fully discharged. This battery is not rechargeable and is soldered onto the PCB. Finding a way to change these over was a frustrating experience and prompted me to explore and invent a better way. The compact DS3231 I use in my projects (shown on the right) have a CR927 battery with solder tabs. These batteries last for years but when they are discharged, the time and configured clock settings are lost when the module is powered down. These tabbed batteries only seem to be available in bulk quantitie ..read more