raspberry pi

Andreas Spiess explains the basic principles of LoRa and LoRaWAN, their pros and cons, link budget and bandwidth. He shows his own gateway and client sending a message to The Things Network.

George Brocklehurst of thoughtbot demonstrates Vim's built-in completion mechanisms, from word, line and block completion to ctags. The aim is to type less and make fewer typos.

A screencast tutorial on Specter, a Clojure library for navigating and transforming nested data structures declaratively, demonstrated in a REPL.

Tech Ingredients builds a pair of large Voigt speakers and explains ported, transmission line and horn designs. It tests them in an anechoic chamber and uses constrained layer damping for the enclosure.

Ben Eater starts a series building a working computer on breadboards around the 6502 microprocessor. In this first part he gets a 'hello world' running from scratch.

Ben Eater explains how VGA signals work and builds a breadboard circuit that produces correct sync timing so a monitor recognizes the signal. He then builds toward displaying an image from simple logic chips.

Ben Eater explains how a USB keyboard communicates, covering the electrical interface, bit and packet encoding, packet contents, and a comparison with PS/2.

Ben Krasnow of Applied Science explains how electrophoretic e-paper displays work and how he modified the driver firmware and waveform lookup tables of a 4.2-inch panel to reach roughly 3Hz partial refresh. It covers the tweakable constants in the refresh process and touches on colored e-ink microcapsules.

The first part of Robert Baruch's series on building a 6800 CPU on an FPGA with nMigen, a Python-based hardware description language. It introduces the HDL while implementing a simpler 6800 core.

Ben Vallack walks through designing a custom keyboard PCB from scratch using Ergogen and KiCad, ending with a gerber file ready to order from a PCB fabricator. The example is a split keyboard.

Applied Science builds a replica Apollo DSKY using an electroluminescent driver circuit and screen-printed conductive ink, with source and PCB files published.

Big Clive gives a 38-minute beginner's guide to identifying common electronic components and what they do. He keeps the maths minimal and aims to fill gaps for people just starting out.

Ben Eater explains how the PS/2 keyboard interface works, covering its clocked serial protocol and scancodes. He builds up the hardware-level understanding needed to read keypresses.

A reupload of Joel Spolsky's talk teaching spreadsheet users the Excel features they are probably missing, such as keyboard navigation, named ranges, tables and lookups. The original disappeared and this copy comes from the Wayback Machine.

Dave Jones of EEVblog shows hand soldering of surface-mount parts, including drag soldering and tack-and-reflow of 0.5mm fine-pitch ICs, with solder paste and hot air.

Markus Triska tours Prolog's most distinctive features, including its use as a database and query language, rule processing, constraint solving and compile-time rewriting. It also covers concise meta-interpreters.

Marco Baringer's tutorial video on SLIME, the Emacs mode for developing Common Lisp. It demonstrates the interactive workflow of working against a live Lisp image.