Author: Al Williams

4451 Articles

How Not To Build An RP2040 Board

October 11, 2023 by 26 Comments

We love that these days you can buy ready-made microcontroller boards that are very capable. But sometimes you need to — or just want to — do it yourself. Unfortunately, you really should design everything twice: once to figure out where all the problems are, and the second time to do it better. If you want to create your own board for the RP2040 then you are in luck. [Jeremy] has made the first (and second) iteration or an RP2040 board and shares with us what he would not do again.

In all fairness, he also has a blog post talking about what he did, so you might want to start there. However, we think his most valuable advice was his final word: Don’t fail to get started on your design. The longest journey, after all, begins with the first step.

His other advice is good, too. For example, don’t plug your new board into a computer because an error in the power supply could take the whole computer out. He also warns you not to do like he did and forget to order the $10 solder stencil with the PCBs.

Some of it is just good advice in general. For example — buy more small components than you think you need. There’s nothing worse than needing three resistors, having three resistors, and then watching one of the three fly across the room or stick to your soldering iron and melt into a pool of slag. Buy ten and you’ll save money in the long run.

In the end, the board did work and what he learned might help you if you decide to tackle a similar project yourself. [Jeremy’s] board is fairly large, but if you have an appetite for something smaller, check out the RPDot or the RP2040 Stamp.

Tiny Tape Cartridge Remembered And A Teardown

October 10, 2023 by 9 Comments

If you want to add sound to something these days, you usually store it digitally. Microcontrollers are cheap and fast, and you can hold a lot of audio on a small flash card or in a ROM. But back “in the day,” storing audio was often done with tape. If you wanted something you could automate, you often turned to an endless loop tape. They had the advantage of not needing rewinding and had a way to sense spots on the tape (usually the start). The 8-track, for example, was an endless loop tape, and radio stations used “carts” (technically Fedelipak cartridges). But what if you wanted to build something tiny? Bandai had the answer, and [Tech Moan] shows the 1986-era tiny carts.

In the US, these appear to be mainly in the realm of novelty items. [Tech Moan] has an Elvis figurine that sings thanks to the tape and a diminutive jukebox. He suspects these must have been used in something else, perhaps in the Japanese market.

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Decoding The 8088

October 9, 2023 by 2 Comments

There is a lot to like about open software, and in some areas, a well-thought-out piece of software can really make a huge impact. A great example of this is the Sigrok project. Creating simple devices that act like a logic analyzer is relatively easy. What’s hard is writing nice software for such a setup including protocol decoders. Sigrok has done it and since it is open, you can add your device and decode your protocol. [GloriousCow] had done the hardware part of interfacing to the 8088 in an IBM PC using an off-the-shelf logic analyzer that uses a customized version of Sigrok. But the output was a CSV file you had to process in a spreadsheet program. The next step: write a decoder for Sigrok to understand 8088 bus cycles.

The post covers the details of writing such a plug-in for Pulseview, the Sigrok GUI. It will also work for the command line interface if you prefer that. The code is in Python.

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Who Needs Sea Monkeys? Get PlanktoScope

October 8, 2023 by 10 Comments

Plankton are tiny organisms that drift around in the ocean. They aren’t just whale food — they are responsible for fixing up to 50% of the world’s carbon dioxide. That, along with their position as the base of many important food chains, makes them interesting to science. Unfortunately, they are tiny and the ocean is huge. Enter Planktoscope. Billed as “an affordable modular quantitative imaging platform for citizen oceanography,” the device is a software-controlled microscope with the ability to deal with samples flowing through.

The software is in Python and uses existing libraries for user interface, image processing, and other tasks. The computing hardware is in the form of a Raspberry Pi. There are actually two prototypes of PlanktoScope available.

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Auto Xylophone Uses Homemade Solenoids

October 8, 2023 by 26 Comments

Want to play the xylophone but don’t want to learn how? [Rachad]’s automatic xylophone might be just the ticket. It uses homemade solenoids to play tunes under computer control. Think of it as a player piano but with electromagnetic strikers instead of piano keys. You can hear the instrument in action in the video below.

Since the project required 24 solenoids, [Rachad] decided to build custom ones using coils of wire and nails. We were amused to see a common curling iron used as an alternate way to apply hot glue when building the coils. The other interesting part of the project was the software. He now uses a toolchain to convert MIDI files into a serial output read by the Arduino. Eventually, he wants to train an AI to read sheet music, but that’s down the road, apparently.

Honestly, we were a bit surprised that it sounded pretty good because we understand that the material used to strike the xylophone and the exact position of the strike makes a difference. We doubt any orchestra will be building one of these, but it doesn’t sound bad to us.

The last one of these we saw did have more conventional strikers if you want to compare. Honestly, we might have just bought the solenoids off the shelf but, then again, we don’t make our own relays either.

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Blaupunkt Tube Radio Is The Sultan Of Radios

October 8, 2023 by 16 Comments

According to [M Caldeira], the Blaupunkt Sultan 24300 was one of the last tube radios made in the 1960s. He’s got one but it needed some tender loving care, and you can see how he approaches a restoration like this in the video below.

The radio was actually in better shape physically than most of the old radios we see. It wasn’t perfect, but it looked good on the outside. Electrically, though, it did need some work, and the dial had problems, too. The first obstacle was identifying exactly the model of the radio since there were a number of Sultan radios produced.

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Fluid Simulation Does The Math

October 6, 2023 by 2 Comments

If you like math, you should enjoy [kynd’s] page about simulating fluid in p5.js. You might still enjoy the pretty colors and shapes if you aren’t into math. What’s scary is that the page promises to have as little math as possible, but there’s still quite a bit. Of course, we are sure you could go even deeper down the rabbit hole.

The algorithm’s core is a pair of 2D arrays representing cells that comprise the display area. One array holds the color of the cell, while another holds a velocity vector of the fluid in the cell. A vector, of course, has both a magnitude and a direction.

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