Author: Al Williams

4016 Articles

I2C The Hard Way

October 21, 2024 by 12 Comments

[Igor] has an AS5600 magnetic rotary encoder chip on a breakout board. Normally, you’d think that was an easy device to work with since it has an I2C interface. But [Igor] wanted to do it the hard way. What’s the hard way? By hand. He directly manipulates the clock and data lines using some push buttons. You can see how it goes in the video below.

This is possible because the controlling device — in this case [Igor] — gets to set the clock rate, and there’s no reason it has to be regular. We have to admit that it never occurred to us to do this, but we have written “bit banged” I2C-like code before.

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Ideal Diodes And How To Build Them

October 19, 2024 by 17 Comments

[Julian] knows that real diodes you can buy don’t work exactly like we say they do. That’s actually pretty common. We routinely ignore things like wire resistance and source resistance in batteries. Diodes have problems that are harder to ignore, such as the forward voltage drop. So, while a real diode will only pass current in one direction, it will also drop some of the voltage. [Julian] shows you how you can get simulated ideal diodes and why you might want them in a recent video you can see below.

The video starts with a simple demonstration and enumerates some of the practical limitations. Then, he pulls out some ideal diode modules. These typically don’t solve every problem, so they aren’t really ideal in the theoretical sense. But they typically appear to have no forward voltage drop.

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Inside The RLL Hard Drive Protocol

October 19, 2024 by 19 Comments

If you are younger than a certain age, RLL probably doesn’t mean much to you. Old consumer-grade hard drives used MFM (modified frequency modulation like a floppy disk uses) and soon went to IDE (integrated drive electronics). There was a brief period when RLL (run length limited) drives were the way to get a little more life out of the MFM technology. [W1ngsfly] has an RLL drive on his bench and uses his scope and some other gear to put it through its paces. You can watch over his shoulder in the video below.

The hardware interface and drive are the same for an MFM and an RLL drive. However, an RLL-aware controller can pack more bits on the same platter by using the newer modulation scheme. Some older disks were good enough for MFM but too sloppy to successfully take an RLL format, but — in theory — any MFM drive could be an RLL drive and vice versa.

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Power Supply PCB Redesign

October 19, 2024 by 6 Comments

We’ve often heard you should do everything twice. The first time is to learn what you need to do, and the second time is to do it right. We bet [Ian Carey] would agree after taking his old linear power supply PCB and changing it to a switching regulator design. You can see more about the project in the video below.

The first power-up revealed a problem with the 3.3V output. We’ve often thought it is harder to troubleshoot a new design than it is to repair something that is known to have worked at one time.

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Smart Glasses Read Text

October 18, 2024 by 6 Comments

You normally think of smart glasses as something you wear as either an accessory or, if you need a little assistance, with corrective lenses. But [akhilnagori] has a different kind of smart eyewear. These glasses scan and read text in the user’s ear.

This project was inspired by a blind child who enjoyed listening to stories but could not read beyond a few braille books. The glasses perform the reading using a Raspberry Pi Zero 2 W and a machine learning algorithm.

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Laser Painting Explained

October 17, 2024 by 7 Comments

If you get an inexpensive diode laser cutter, you might have been disappointed to find it won’t work well with transparent acrylic. The material just passes most of the light at that wavelength, so there’s not much you can do with it. So how did [Rich] make a good-looking sign using a cheap laser? He used a simple paint and mask technique that will work with nearly any clear material, and it produces great-looking results, as you can see in the video below.

[Rich] starts with a piece of Acrylic covered with paper and removes the paper to form a mask. Of course, even a relatively anemic laser can slice through the paper covering with no trouble at all. He also cuts an outline, which requires a laser to cut the acrylic. However, you could easily apply this to a rectangular hand-cut blank. Also, most diode lasers can cut thin acrylic, but it doesn’t always come out as cleanly as you’d like.

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Module Makes Noisy Projects Easy

October 16, 2024 by 7 Comments

You want to add voice, music, or sound effects to your project. What do you do? Sure, it is easy enough to plug a Raspberry Pi or some other tiny computer, but that’s not always desirable from a power, space, or cost point of view. [Mellow_Labs] shows a module that makes it simple to add sound to any project. The little board is just big enough to house a speaker and doesn’t cost much. Check it out in the video below.

The device allows you to preload tracks as MP3 files. There are two ways to control it: via a serial port, or using a single pin that can accept commands like you might expect from a MP3 player, like play and next track.

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