Author: Al Williams

4378 Articles

Over The Counter Glucose Monitor Dissected

February 23, 2025 by 37 Comments

If you deal with diabetes, you probably know how to prick your finger and use a little meter to read your glucose levels. The meters get better and better which mostly means they take less blood, so you don’t have to lacerate your finger so severely. Even so, taking your blood several times a day is hard on your fingertips. Continuous monitoring is available, but — until recently — required a prescription and was fairly expensive. [Andy] noticed the recent introduction of a relatively inexpensive over-the-counter sensor, the Stelo CGM. Of course, he had to find out what was inside, and thanks to him, you can see it, too.

If you haven’t used a continuous glucose monitor (CGM), there is still a prick involved, but it is once every two weeks or so and occurs in the back of your arm. A spring drives a needle into your flesh and retracts. However, it leaves behind a little catheter. The other end of the catheter is in an adhesive-backed module that stays put. It sounds a little uncomfortable, but normally, it is hardly noticeable, and even if it is, it is much better than sticking your finger repeatedly to draw out a bunch of blood.

Continue reading “Over The Counter Glucose Monitor Dissected” →

Retrotectacular: Ham Radio As It Was

February 21, 2025 by 22 Comments

We hear a lot about how ham radio isn’t what it used to be. But what was it like? Well, the ARRL’s film “The Ham’s Wide World” shows a snapshot of the radio hobby in the 1960s, which you can watch below. The narrator is no other than the famous ham [Arthur Godfrey] and also features fellow ham and U.S. Senator [Barry Goldwater]. But the real stars of the show are all the vintage gear: Heathkit, Swan, and a very oddly placed Drake.

The story starts with a QSO between a Mexican grocer and a U.S. teenager. But it quickly turns to a Field Day event. Since the film is from the ARRL, the terminology and explanations make sense. You’ll hear real Morse code and accurate ham lingo.

Continue reading “Retrotectacular: Ham Radio As It Was” →

A New 8-bit CPU For C

February 21, 2025 by 61 Comments

It is easy to port C compilers to architectures that look like old minicomputers or bigger CPUs. However, as the authors of the Small Device C Compiler (SDCC) found, pushing C into a typical 8-bit CPU is challenging. Lessons learned from SDCC inspired a new 8-bit architecture, F8. This isn’t just a theoretical architecture. You can find an example Verilog implementation in the SDDC project and on GitHub. The name choice may turn out to be unfortunate as there was an F8 CPU from Fairchild back in the 1970s that apparently few people remember.

In the video from FOSDEM 2025, [Phillip Krause] provides a nice overview of the how and why of F8. While it might seem odd to create a new 8-bit CPU when you can get bigger CPUs for pennies, you have to consider that 8-bit machines are more than enough for many jobs, and if you can squeeze one into an FPGA, it might be a good choice as opposed to having to get a bigger FPGA to hold your design and a 32-bit CPU.

Continue reading “A New 8-bit CPU For C” →

Pico Gets A Speed Bump

February 20, 2025 by 28 Comments

The release notes for the 2.1.1 Raspberry Pi Pico SDK have a late holiday present: The RP2040 chip is now certified to run at 200 MHz if you use at least 1.15V as the supply voltage.

Previously, the certified speed was 125 MHz, although it was well-known you could overclock the device. By default, the 125 MHz figure is still what you’ll get, though. If you want a higher frequency, you need to set SYS_CLK_MHZ to 200 before doing a build. Continue reading “Pico Gets A Speed Bump” →

Be Careful What You Ask For: Voice Control

February 19, 2025 by 71 Comments

We get it. We also watched Star Trek and thought how cool it would be to talk to our computer. From Kirk setting a self-destruct sequence, to Scotty talking into a mouse, or Picard ordering Earl Grey, we intuitively know that talking to a computer is better than typing, right? Well, computers talking back and forth to us is no longer science fiction, and maybe we aren’t as happy about it as we thought we’d be.

We weren’t able to pinpoint the first talking computer in fiction. Asimov and van Vogt had talking computers in the 1940s. “I, Robot” by Eando Binder, and not the more famous Asimov story, had a fully speaking robot in 1939. You could argue that “The Machine” in E. M. Forster’s “The Machine Stops” was probably speaking — the text is a little vague — and that was in 1909. The robot from Metropolis (1927) spoke after transforming, but you could argue that doesn’t count.

Meanwhile, In Real Life

In real life, computers weren’t as quick to speak. Before the middle of the twentieth century, machine-generated speech was an oddity. In 1779, a mechanical contrivance by Wolfgang von Kempelen, famous for the mechanical Turk chess-playing automaton, could form simple words. By 1939, Bell Labs could do even better speech synthesis electronically but with a human operator. It didn’t sound very good, as you can see in the video below, but it was certainly expressive.

Continue reading “Be Careful What You Ask For: Voice Control” →

In A World Without USB…

February 19, 2025 by 26 Comments

It is easy to forget that many technology juggernauts weren’t always the only game in town. Ethernet seems ubiquitous today, but it had to fight past several competing standards. VHS and Blu-ray beat out their respective competitors. But what about USB? Sure, it was off to a rocky start in the beginning, but what was the real competition at that time? SCSI? Firewire? While those had plusses and minuses, neither were really in a position to fill the gap that USB would inhabit. But [Ernie Smith] remembers ACCESS.bus (or, sometimes, A.b) — what you might be using today if USB hadn’t taken over the world.

Back in the mid-1980s, there were several competing serial bus systems including Apple Desktop Bus and some other brand-specific things from companies like Commodore (the IEC bus) and Atari (SIO). The problem is that all of these things belong to one company. If you wanted to make, say, keyboards, this was terrible. Your Apple keyboard didn’t fit your Atari or your IBM computer. But there was a very robust serial protocol already in use — one you’ve probably used yourself. IIC or I2C (depending on who you ask).

Continue reading “In A World Without USB…” →

DaVinci’s New Threads

February 16, 2025 by 16 Comments

Last year, we saw [How To Make Everything’s] take on [DaVinci’s] machine for cutting threads. However, they stopped short of the goal, which was making accurate metal screw threads. After much experimentation, they have a working solution. In fact, they tried several different methods, each with varying degrees of success.

Some of the more unusual methods included heating a bar red hot and twisting it, and casting a screw out of bronze. The last actually worked well with a normal screw as the mold, although presumably, a good wood or wax shape would have resulted in a workable mold, too.

Continue reading “DaVinci’s New Threads” →