A simple digital generator
In this project I developped a simple yet powerful digital (TTL) generator. Built around an Arduino Nano, the generator fits in a small portable 3d-printed package but it features single step or square-formed periodic signals, manual control of the delivering time or a preset number of periods, and control via the serial connection as well as a LCD with a selectable menu. Last but not least: there is a switch to choose between 3.3V and 5V.
Direct control of the XL 320 servo with a Raspberry
This post introduces a custom C++ library to control the popular Dynamixel XL 320 servo directly with a Raspberry Pi 4, without the need for an additional controller/shield like the OpenCM board. You'll just need a level shifter to drive the motor and LED and an additional logic gates IC in case you want to read the servo's output, but these are cheap and popular electronic components. The Rasberry configuration and wiring are included, with everything you need to have a working setup rapidly.
A foldable shield for face protection
In the context of the pandemic of SARS-CoV-2 I've been actively working on a design of foldable head shield that could be produced in large quantities. In this post I provide all the details about this project, including the blueprints and production instructions for makers.
Extended safety eyewear lenses
The current pandemic of COVID-19 compels medical staff to rapidly adapt the equipment at their disposal to manage this threat. In this post I show how to extend the protection offered by disposable safety eyeware lenses. I also share the blueprint and cut files so that anyone can easily reproduce it.
Mask holders to relieve ear pain
In the emergency of the COVID-19 pandemic, a large numbers of caregivers are at the frontline to perform tests an assist patients. Among other protection equipments, the disposable masks with elastic straps may be worn all day long and cause pain at the back of the ears. I designed a small plastic ribbon to prevent this, and I share the blueprint and cut files so that anyone can easily reproduce it.
A new design for ultimate hand signals
Hand signals play an important role in self-refereeing sports. Here I've made a new design for the ultimate hand signals, which fits nicely on a disc! A great way to improve your knowledge of the rules, and the spirit of the game in general.
Mechanical cheatsheet for CAD and 3D printing
Here is a one-page cheatsheet with selected info for standard metric screws, threaded inserts, hexagonal nuts and square nuts. In addition you also have the dimensions of the holes to insert in a design for 3D printing. To print and pin on your wall if you design awesome parts on a regular basis!
A complete 8-bit cheatsheet
Here is a one-page cheatsheet with all decimal, hexadecimal and binary codes for all digits from 0 to 255. In addition you also have the corresponding characters (i.e. the standard ASCII characters for the first 128 digits) which is often useful to have on hand. To print and pin on your wall if you are often programming devices at a low-level!
A stackable manifold for micro-valves
There can be numerous good reasons to use a computer-controlled microvalve: with low dead volumes and fast switching times they can be used for millifluidics, microfluidics or automation. Two common pitfalls are the driving electronics and the mechanical connection of the valve with the circuit. In this post I detail how to build a stackable manifold with Luer connectors for microvalves driven by a digital signal. Download all conception files for easy replication!
Matlab syntax tricks
A big asset of the Matlab language is that the syntax is simple to learn. But besides a seamingly poor set of syntax rules, there are several tricks that most people ignore. This post gathers a few not-totally-mainstream syntax tricks, which may reveal useful to anyone willing to improve his/her coding style and efficiency.
A basic Arduino serial server
When using an arduino as an acquisition and control board for a computer, the very first thing to do is to establish a communication between the Arduino (the server) and the computer (the client). Serial communication via USB is the simplest choice, and in this post we will see how to transform an Arduino into a basic serial server with just a simple - yet powerful - sketch.
Tracking object orientation with image moments
Object tracking is often reduced to recording the trajectory of the center of mass, and there is a simple reason for this: one only needs to compute the mean values of the horizontal and vertical indexes of the pixels, which is easy and fast. But what if one wants to track the object's orientation ? To do this, my favorite method is a simple and elegant approach involving image moments.
Fast clusterization of adjacency matrices
In this post I review three different methods to extract clusters from an adjacency matrix. A simple benchmark compares their performance and show that the reverse Cuthill-McKee algorithm improves execution time by a factor 30 as compared to brute force.
