From Mobility to Mowing: Hacking Surplus Medical Equipment for an Autonomous Lawnmower

https://invidious.privacyredirect.com/watch?v=fLue5p1RQMk

Imagine an autonomous lawnmower, precisely navigating your yard with no human intervention. Now, imagine its heart and soul is a repurposed electric wheelchair. This is the premise of a fascinating project where a Jazzy Select Mobility Scooter Wheelchair is transformed into an autonomous mower. By hacking its control system, Brent is leveraging the scooter’s robust drive motors and motor controller for a completely different purpose.

The core of this project involves reverse-engineering the wheelchair’s control system. The key is its three-pin interface, which consists of a 24V battery line, a ground, and a...

A NeoPixel Driver using AVR Hardware [2]

My previous article described a driver for NeoPixel (WS2812) LED displays using the SPI peripheral on an AVR processor in conjunction with a Timer/Counter and the Configurable Custom Logic (CCL).

This article shows how to go one step further, and eliminate most of the interconnections between the pins on that circuit by taking advantage of an additional feature of recent AVR processors, the Event System:

NeoPixel Driver using the hardware peripherals and Event System in an AVR128DA28.

The article A NeoPixel Driver using AVR Hardware [1] described a program for AVR processors that created the stream of pulses needed by the NeoPixel protocol,...

Применение дешевых NFC меток NTAG213/215/216 работающих по стандарту ISO/IEC 14443A для дома и других сфер применения

Рассматриваются современные NFC метки NTAG213, NTAG215 и NTAG216 разработанные компанией NXP Semiconductors, работающие по стандарту ISO/IEC 14443-A. Эти метки очень популярны благодаря своей доступности, универсальности и совместимости с большинством NFC-считывателей, включая смартфоны. Фактор дешевизны и доступности определяет массовое распространение этих NFC-меток. Что такое NFC NFC или Near Field Communication – это технология «связи ближнего действия». Она позволяет пользователям обмениваться информацией, просто поднося устройства друг к другу на расстояние до 10 см. По сути NFC это частный случай RFID (Radio Frequency Identification) — механизма радиочастотного обмена данными, хранящимися в так называемых транспондерах или метках, который основан на стандартах ISO/IEC 18092 NFC...

Why do people keep writing about the imaginary compound Cr2Gr2Te6?

I was reading the latest issue of the journal Science, and a paper mentioned the compound Cr2Gr2Te6. For a moment, I thought my knowledge of the periodic table was slipping, since I couldn't remember the element Gr. It turns out that Gr was supposed to be Ge, germanium, but that raises two issues. First, shouldn't the peer reviewers and proofreaders at a top journal catch this error? But more curiously, it appears that this formula is a mistake that has been copied around several times.

The Science paper [1] states, "Intrinsic ferromagnetism in these materials was discovered in Cr2Gr2Te6 and CrI3 down to the bilayer...

Here be dragons: Preventing static damage, latchup, and metastability in the 386

I've been reverse-engineering the Intel 386 processor (from 1985), and I've come across some interesting circuits for the chip's input/output (I/O) pins. Since these pins communicate with the outside world, they face special dangers: static electricity and latchup can destroy the chip, while metastability can cause serious malfunctions. These I/O circuits are completely different from the logic circuits in the 386, and I've come across a previously-undescribed flip-flop circuit, so I'm venturing into uncharted territory. In this article, I take a close look at how the I/O circuitry protects the 386 from the "dragons" that can destroy it.

August Update: Note-able Tablet Updates

Hello RSS users! In this update we announce a new community manager, updates to the PineTab2 and PineNote, FreeBSD on the PinePhone Pro, a guide on upstreaming PinePhone Pro patches and a small bit for you Pinecil users.

A Quick Community Update on PinePhone Pro and What’s Next

Hey everyone! As many have noticed, the PinePhone Pro is currently out ot stock on the Pine Store. Unfortunately we have to deliver you the following news: the PinePhone Pro is officially discontinued. We were told it didn’t sell well enough to keep production going. But the good news for current owners are that spare parts will still be made for up to two years, depending on demand. Meanwhile, the trusty PinePhone (A64) is still alive and kicking, and Pine Store plans to keep it rolling for about two more years.

Candle Flame Oscillations as a Clock

Todays candles have been optimized for millenia not to flicker. But it turns out when we bundle three of them together, we can undo all of these optimizations and the resulting triplet will start to naturally oscillate. A fascinating fact is that the oscillation frequency is rather stable at ~9.9Hz as it mainly depends on gravity and diameter of the flame. 

We use a rather unusual approach based on a wire suspended in the flame, that can sense capacitance changes caused by the ionized gases in the flame, to detect this frequency and divide it down to 1Hz.

Candlelight is a...

A CT scanner reveals surprises inside the 386 processor's ceramic package

Intel released the 386 processor in 1985, the first 32-bit chip in the x86 line. This chip was packaged in a ceramic square with 132 gold-plated pins protruding from the underside, fitting into a socket on the motherboard. While this package may seem boring, a lot more is going on inside it than you might expect. Lumafield performed a 3-D CT scan of the chip for me, revealing six layers of complex wiring hidden inside the ceramic package. Moreover, the chip has nearly invisible metal wires connected to the sides of the package, the spikes below. The scan also revealed that the 386 has two separate power...

Самодельные французские радиолампы 1920-х годов. Часть 4. Вакуумный триод

Финально-десертная часть эпопеи М. Н. Минье — французского коллеги-любителя из прошлого, в своё время и своими невеликими возможностями (часть 1) изловчавшегося делать практические усилительные лампы, пусть и невысоких достоинств, для своего радио. Основа основ для таких работ — вакуумный насос для откачки собранных приборов, сделан им самостоятельно — стеклянный, ртутно-капельного типа (часть 2), позже дооснащённый простейшим индикатором разрежения — разрядной трубкой (Гейслера) (часть 3). Попутно освоен необходимый ряд стеклодувных операций и простые учебно-тренировочные лампы накаливания. При этом мастерская нашего энтузиаста (попробуем себе это представить!) не оснащена сетевым электричеством и горючим газом, для горячей работы со стеклом применена самодельная горелка-февка на жидком топливе и с...