Ptychography For High Resolution Microscopy

March 5, 2025 by Al Williams No comments

Nowadays, if you have a microscope, you probably have a camera of some sort attached. [Applied Science] shows how you can add an array of tiny LEDs and some compute power to produce high-resolution images — higher than you can get with the microscope on its own. The idea is to illuminate each LED in the array individually and take a picture. Then, an algorithm constructs a higher-resolution image from the collected images. You can see the results and an explanation in the video below.

You’d think you could use this to enhance a cheap microscope, but the truth is you need a high-quality microscope to start with. In addition, color cameras may not be usable, so you may have to find or create a monochrome camera.

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Speaking Computers From The 1970s

March 5, 2025 by Al Williams 19 Comments

Talking computers are nothing these days. But in the old days, a computer that could speak was quite the novelty. Many computers from the 1970s and 1980s used an AY-3-8910 chip and [InazumaDenki] has been playing with one of these venerable chips. You can see (and hear) the results in the video below.

The chip uses PCM, and there are different ways to store and play sounds. The video shows how different they are and even looks at the output on the oscilloscope. The chip has three voices and was produced by General Instruments, the company that initially made PIC microcontrollers. It found its way into many classic arcade games, home computers, and games like Intellivision, Vectrex, the MSX, and ZX Spectrum. Soundcards for the TRS-80 Color Computer and the Apple II used these chips. The Atari ST used a variant from Yamaha, the YM2149F.

There’s some code for an ATmega, and the video says it is part one, so we expect to see more videos on this chip soon.

General instruments had other speech chips, and some of them are still around in emulated form. In fact, you can emulate the AY-3-8910 with little more than a Raspberry Pi.

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Inexpensive Powder Coating

March 4, 2025 by Al Williams 14 Comments

[Pete] had a friend who would powder coat metal parts for him, but when he needed 16 metal parts coated, he decided he needed to develop a way to do it himself. Some research turned up the fluid bed method and he decided to go that route. He 3D printed a holder and you can see how it all turned out in the video below.

A coffee filter holds the powder in place. The powder is “fluidized” by airflow, which, in this case, comes from an aquarium pump. The first few designs didn’t work out well. Eventually, though, he had a successful fluid bed. You preheat the part so the powder will stick and then, as usual, bake the part in an oven to cure the powder. You can expect to spend some time getting everything just right. [Pete] had to divert airflow and adjust the flow rate to get everything to work right.

With conventional powder coating, you usually charge the piece you want to coat, but that’s not necessary here. You could try a few other things as suggested in the video comments: some suggested ditching the coffee filter, while others think agitating the powder would make a difference. Let us know what you find out.

This seems neater than the powder coating guns we’ve seen. Of course, these wheels had a great shape for powder coating, but sometimes it is more challenging.

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Tech In Plain Sight: Shopping Cart Locks

February 28, 2025 by Al Williams 46 Comments

Shopping carts are surprisingly expensive. Prices range up to about $300 for a cart, which may seem like a lot, but they have to be pretty rugged and are made to work for decades. Plastic carts are cheaper, but not by much.

And carts have a way of vanishing. We’ve seen estimates that cart theft costs hundreds of millions of dollars worldwide annually. To stem the tide, stores sometimes pay a reward to people to round up carts off the street and return them to the store — it’s cheaper than buying a new one. That led [Elmer Isaacks] to patent a solution to this problem in 1968.

The [Isaacks] system used lots of magnets. A cart leaving the store had a brake that would be armed by running over a magnet. Customers were expected to follow a path surrounded by magnets to prevent the brake from engaging. If you left the track, a rod passing through the wheel locked it.

A third magnet would disarm the brake when you entered the store again. This is clever, but it has several problems. First, you have to insert magnets all over the place. Second, if someone knows how the system works, a simple magnet will hold the brake off no matter what. Continue reading “Tech In Plain Sight: Shopping Cart Locks” →

Linux Fu: USB Everywhere

February 27, 2025 by Al Williams 20 Comments

It is a common problem: I have a USB device on a computer out in the shop, and I want to use it from the comfort of my office. What to do? Well, you could remote desktop into the distant machine. But, honestly, I always find any remote desktop more than ssh clunky and somewhat undesirable. Fortunately, Linux can do virtually anything if you only know how to do it. So, this time, I’ll show you how to transport a USB device over your network. Of course, I have a network that reaches out to the shop. It should be a simple matter to tell my desktop machine that one of its USB devices lives across the network. Well, it wasn’t that simple, but it is doable.

The Tools

The whole thing involves a program called usbip. That should be the end of it, but of course, it isn’t. In order for this to work, both machines on the network will need some kernel modules and a daemon on the server: the machine with the USB devices to share.

You may be able to install usbip from your package manager. On Ubuntu, it is in the linux-tools-common package, so a simple apt-get might give you everything you need. I wasn’t so lucky. Continue reading “Linux Fu: USB Everywhere” →

Tech In Plain Sight: Magsafe, And How To Roll Your Own

February 25, 2025 by Al Williams 7 Comments

Apple likes magnets. They started out with magnetic laptop chargers and then graduated to a system that magnetically holds the phone, charges it, and can facilitate communication between the phone and a charger or other device. Even if you are like me and have no Apple devices, you can retrofit other phones to use Magsafe accessories. In fact, with a little work, you can build your own devices. Regardless, the technology is a clever and simple hack, and we are just a little sorry we didn’t think of it.

Terms

Using a magnet to attach a phone isn’t a new idea. But, historically, the phone had either a metal back or an adhesive metal plate attached that would stick to the magnet. This wouldn’t necessarily help with charging, but was perfectly fine for holding the device. The problem is, it is hard to wirelessly charge the phone through the metal.

Magsafe can do several different things. Obviously, it can attach the phone magnetically. However, since it is a ring shape, you can still have a charging coil in the middle of the ring. Better still, the Magsafe system will align the phone and charger with a satisfying click when you put them together.

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To Test A (Smart) LED

February 24, 2025 by Al Williams 14 Comments

Adding LEDs to a project used to be enough to make it cool. But these days, you need arrays of addressable multi-color LEDs, and that typically means WS2812B or something similar. The problem is that while it was pretty easy to test garden-variety LEDs, these devices can be a bit harder to troubleshoot. [Gokux] has the answer, as you can see in the video below.

Testing these was especially important to [Gokux] because they usually swipe the modules from other modules or LED strips. The little fixture sends the correct pulses to push the LED through several colors when you hold it down to the pads.

However, what if the LED is blinking but not totally right? How can you tell? Easy, there’s a reference LED that changes colors in sync with the device under test. So, if the LEDs match, you have a winner. If not… well, it’s time to desolder another donor LED.

This is one of those projects that you probably should have thought of, but also probably didn’t. While the tester here uses a Xiao microcontroller, any processor that can drive the LEDs would be easy to use. We’d be tempted to breadboard the tester, but you’d need a way to make contact with the LED. Maybe some foil tape would do the trick. Or pogo pins.

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