Another one of my “lockdown projects” involves a 7.5 inch e-Paper display from Waveshare. Instead of your ordinary computer display, which bombards your eyes with light, e-Paper displays are more similar to paper. By making a pixel more or less reflective (using a technique known as ‘E-ink’), an e-Paper display …
Digital RGB LED strips are strips of LED lights that can be controlled individually, which makes them really versatile for use in e.g. home automation. Throughout my home there are several strips, each adapting their hue to the current time of day and showing all sorts of information, such as …
Over the holidays I wrote a tiny ray tracer in Rust. A ray tracer is a program that renders a 3D image by simulating the way light travels between light sources and a camera. Advanced versions of ray tracing techniques are used to render 3D movies such as the famous …
A blockchain allows different entities share a database without having to entrust that database to a single entity. Catena provides an SQL database on top of a blockchain, providing all the benefits of blockchains (resiliency, distributed operation, openness) while providing a familiar interface to its users.
The Internet of Things promises to connect virtually all devices and make sensor data ubiquitously available. Instead of storing all this data in a central location, you can use a peer-to-peer network to store sensor data. Using a peer-to-peer network has several advantages. First of all, the infrastructure is ‘free’ (although in …
Chartly.js is a web component that allows end users to create (‘program’) a chart using the Blockly visual programming environment. Charts are ‘compiled’ to a JSON specification for the chart. At run time, Chartly interprets the JSON and draws the chart using d3.js. Chartly is open-source under the MIT license. …
Automated bots abuse comment forms to put advertisements on websites. Traditional CAPTCHAs prevent spam by exploiting the fact that computers cannot solve a particular problem easily, and that humans that can solve them are scarce/expensive/slow (but available in the regular use case). Proof of work, by contrast, exploits the fact that …
Ll.js provides a simple way of parsing about anything using a recursive-descent algorithm. The grammar to be parsed is written in a friendly DSL (domain specific language) in JavaScript itself that resembles EBNF. Each parser term can be annotated with a function; when the final parse tree includes the term, …
