Author: Al Williams

4502 Articles

Electronic Covid Test Tear Down Shows Frustrating Example Of 1-Time-Use Waste

October 17, 2021 by 68 Comments

The latest video from [TheSignalPath] is a result of his purchase of a home COVID-19 test. He found an electronic version that connects to your cell phone and displays the results on the phone. The device is an antigen test and, internally, works like the home tests that show the results using lines similar to a pregnancy test. So, somehow, the phone version reads the lines and communicates with the phone. But how? That’s the point of the video, which you can see below.

In a traditional test, there’s a control line that has to appear to show that the test was done correctly. Then a line under that indicates detection of the virus. The circuit board inside the electronic test has a plastic unit onboard that contains a similar strip and has optical sensors for both the reference line and the detection line. Since it is essentially an optical device — there are some lenses in the strip assembly that look like they are detecting the dye as it moves through the strip with LEDs onboard to shed light on the situation.

Under the microscope, the CPU is a typical Bluetooth-capable ARM chip from Nordic. The board did power up, but the device is made to only operate once because of the test strip. The video notes — and we agree — it seems wasteful to create an entire Bluetooth-enabled microcontroller board with optical components just to read a strip one time that is pretty easy to read to start with. We’ll stick with the simple test strip. Still, it is interesting to see the insides.

If you want to read more about antigen tests, we covered that. We also talked about PCR testing.

Continue reading “Electronic Covid Test Tear Down Shows Frustrating Example Of 1-Time-Use Waste” →

Fail Of The Week: Magnetic Levitation

October 16, 2021 by 26 Comments

We are big fans of the little desktop magnetic levitation setups that float a small object on a magnet. As [3D Printed Life] points out, they look like magic. He was surprised that the commercial units use analog electronics. He decided to build a digital version but didn’t know what he was getting into. He details his journey in the video you can see below.

Along with a custom control board, he decided to wind his own electromagnets. After finding that tedious he built a simple coil winder to automate some of the work.

Continue reading “Fail Of The Week: Magnetic Levitation” →

Learn DMX512 Basics

October 15, 2021 by 11 Comments

If you’ve done anything with modern lighting effects, you’ve probably heard of DMX, also known as DMX512. Ever wonder what’s really happening under the hood? If so, then you should have a look at [EEForEveryone’s] video on the topic, which you can see below.

At the core, the DMX512 uses RS485, but adds software layers and features. The video uses the OSI model to show how the system works.

Continue reading “Learn DMX512 Basics” →

Better History Through X-Rays

October 15, 2021 by 7 Comments

Even if you aren’t a giant history buff, you probably know that the French royal family had some difficulties in the late 1700s. The end of the story saw the King beheaded and, a bit later, his wife the famous Marie Antoinette suffered the same fate. Marie wrote many letters to her confidant, and probable lover, Swedish count Axel von Fersen. Some of those letters have survived to the present day — sort of. An unknown person saw fit to blot out parts of the surviving letters with ink, rendering them illegible. Well, that is, until now thanks to modern x-ray technology.

Anne Michelin from the French National Museum of Natural History and her colleagues were able to foil the censor and they even have a theory as to the ink blot’s origin: von Fersen, himself! The technique used may enable the recovery of other lost portions of historical documents and was published in the journal Science Advances.

Continue reading “Better History Through X-Rays” →

RISC-V In… Typescript?

October 14, 2021 by 8 Comments

We are accustomed to seeing RISC-V implementations in Verilog or VHDL, but [Low Level JavaScript] has one in TypeScript. Before you dismiss it as a mere emulator, know that the project relies on gateware-ts, a conversion between TypeScript and Verilog. From there, you can actually put the CPU on an FPGA. You can see the launch video below and there is one development video as well as, presumably, more to come.

We aren’t sure if many FPGA designers will be willing to switch to TypeScript. But if you are comfortable with it, it might open up FPGA development without having to learn as much of a new language.

Continue reading “RISC-V In… Typescript?” →

Solar Power Goes Back To 1910 Tech

October 13, 2021 by 41 Comments

If you want to read about a low-tech approach to solar cells invented — and forgotten — 40 years before Bell Labs announced the first practical silicon solar cell, we can’t promise the website, Low Tech Magazine, will be available. Apparently the webserver it is on is solar-powered, and a disclaimer mentions that it sometimes goes offline.

The article by [Kris De Decker] tells of George Cove and includes a picture from 1910 of the inventor standing next to what looks suspiciously like a solar panel (the picture above is from a 1909 issue of Technical World Magazine). His first demonstration of the technology was in 1905 and there is a picture of another device from 1909 that produced 45 watts of power using 1.5 square meters with a conversion efficiency of 2.75%. That same year, a new prototype had 4.5 square meters and used its 240-watt output to charge 5 lead-acid batteries. The efficiency was about 5%.

Continue reading “Solar Power Goes Back To 1910 Tech” →

This Homemade Mass Spectrometer Works

October 12, 2021 by 9 Comments

Hats off to [Paul Brooking] as he shows off his homemade mass spectrometer in two recent videos you can see below. The first video demonstrates that the device works. The second video shows details about how it was made.

It’s not a good starter project, requiring quite a bit of sophisticated gear including two-stage vacuum pumps, Peltier cold plates, and ion sources, but if you aren’t familiar with mass spectrometers the basic idea is simple enough. You take a sample and bombard it with electrons. This creates a stream of ions of the component parts of the sample. Ions of heavy elements, obviously, weigh more than ions of lighter elements. A magnetic field deflects the ions, and the lighter ones are deflected more than the heavier ones. By detecting ions at a certain spot in the deflected beam, you can determine the relative amount of ions at a certain mass.

Continue reading “This Homemade Mass Spectrometer Works” →