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The Sensaura Project

The reason things have been quiet on this site for the past few months is because I have been working on putting together a new project called Sensaura - a scalable and extensible platform for building and deploying wireless sensors. This post provides and introduction to the goals of the project and links to the resources I've set up for it so far. Some Background I've noticed that many of the projects I've been working on over the past few years have a number of similar properties; most of them were small, battery powered devices sending data back over some sort of wireless connection. I've…

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ARM Based Sensor Nodes

One idea I have had in the back of my mind for a long time is a framework for small, low power wireless sensors that are easy to build up and deploy around the house and garden. Some of my first experiments were based around an ATmega CPU and the NRF24L01 wireless transceiver. This is hardly a unique idea, projects like this one and this one have been around for a while. More recently I moved to using an ARM processor as the CPU core instead of an AVR, going as far to start building up a prototype based around the XMC1100 processor. A few months ago I found out that Silicon Labs were running a…

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CNC Updates

It has been a long time since the last post but I certainly haven't been idle in the Lab. Most of my time has been spent working on my larger CNC machine (a CN3020T) including a number of control board redesigns and fine tuning a PCB milling workflow. In my last update I described a simple ATmega328p based board running GRBL. That worked fairly well to control the small linear stepper assemblies I bought on eBay so I decided to use a similar board to control my larger CN3020T machine (which I've been having problems with for a while). To actually drive the stepper motors I bought a set of sing…

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A Simple CNC Machine - Part 3

Another update on my mini-CNC project - progress has been a little slower than I hoped for but I've reached an important milestone now - moving motors! As you can see there are some issues with the precision of the movement - each of those moves is supposed to be 20mm. It doesn't quite make the full 20mm and doesn't return to the same starting point. I'll discuss those issues later in the post but first I would like to talk about the circuit itself. I intended to use the GRBL firmware from the start which requires an ATmega328p with an external 16MHz oscillator. The circuit I used is a basic m…

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A Simple CNC Machine - Part 2

In this second post about my small CNC machine I walk through the process of etching a PCB and building up the controller circuit. The board layout I came up with is shown above - there are more jumper wires than I would have liked and it is not exactly a compact design. Some of these issues are hard to avoid on a single sided board and, truth be told, I didn't spend a lot of time trying to opimise it. My main goal was to fit it on a 75mm x 150mm panel which is the normal size PCB panel I buy. The next step is to make sure the components fit and I haven't made any alignment errors. The image a…

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