Silencing A 3D Printer With Acoustic Foam Isn’t That Easy

September 20, 2023 by 23 Comments

3D printers are supremely useful tools, but their incessant whining and droning can be distracting and tiresome. [Handy Bear] decided to try some simple ways to quieten down their printer using acoustic foam, with mixed results.

The video starts by exploring two different acoustic foams; one black, one white. The latter was found to hold a flame when ignited, making it a poor choice for a 3D printer with many hot components. The black foam, advertised for use in automotive installations, was reluctant to burn at all, and so made a safer choice.

The UP Mini 3 printer is then disassembled to receive its soundproofing treatment. The printer’s various panels all got a healthy lashing of thick sticky insulating foam. This took some work, thanks to the need to cut around various ribs and screw bosses on the panels. Cut appropriately, though, the printed was able to be reassembled neatly with its foam hidden inside.

Unfortunately, the work didn’t have a great effect on the printer’s sound output. That’s perhaps unsurprising, given it still has uninsulated panels like the front window which are still free to radiate sound. The foam did help cut down on fan noise and high-pitch sounds from the printer, but the annoying medium and low pitched noises from the printer’s motors were still very audible.

Using an enclosure or a quieter stepper driver are probably more effective DIY methods to quiet a noisy printer; share your own ideas in the comments. Video after the break.

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Spooky Noise Box Plays War Drums

September 20, 2023 by 6 Comments

What do you have cooked up to scare trick-or-treaters this Halloween? We humbly suggest adding in some type of noise box, especially one like this offering from [Paisley Computer] that uses reverb and other effects to achieve chilling, thrilling sounds.

As you can see, this instrument is essentially a bunch of doodads affixed to and through a cigar box. And as you’ll hear in the first video after the break, the various rubber bands make great drum sounds. The springs are nice, too, but our personal favorite has to be the head massager thing. Shhhing!

Inside the box you’ll find a guitar jack and some piezos glued to the underside of the top surface, but you’ll also find springs mounted across the inside that add to the resonance of the cigar box.

You can use either an interface and DAW or an effects pedal chain to really make things freaky, and [Paisley Computer] does a showdown between Focusrite interface versus various stomp pedals in the second video. In the third video, we learn how to make one of our own.

Do you like the idea of a spring reverb? How about a really big one that sounds sort of Satanic?

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Cold Metal Fusion For 3D Printing

September 20, 2023 by 13 Comments

When you see the term cold fusion, you probably think about energy generation, but the Cold Metal Fusion Alliance is an industry group all about 3D printing metal using Selective Laser Sintering (SLS) printers. The technology promoted by Headmade Materials typically involves using a mix of metal and plastic powder. The resulting part is tougher than you might expect, allowing you to perform mechanical operations on it before it is oven-sintered to remove the plastic.

The key appears to be the patented powder, where each metal particle has a thin polymer coating. The low temperature of the laser in the SLS machine melts the polymer, binding the metal particles together. After printing, a chemical debinding system prepares the part — which takes twelve hours. Then, you need another twelve hours in the oven to get the actual metal part.

You might wonder why we are interested in this. After all, SLS printers are unusual — but not unheard of — in home labs. But we were looking at the latest offerings from Nexa3D and realized that the lasers in their low-end machines are not far from the lasers we have in our shops today. The QLS230, for example, operates at 30 watts. There’s plenty of people reading this that have cutters in that range or beyond out in the garage or basement.

We aren’t sure what a hobby setup would look like for the debinding and the oven steps, but it can’t be that hard. Maybe it is time to look at homebrew SLS printers again. Of course, the powder isn’t cheap and is probably hard to replace. We saw a 20 kg tub of it for the low price of €5,000. On the other hand, that’s a lot of powder, and it looks like whatever doesn’t go into your part can be reused so the price isn’t as bad as it sounds. We’d love to see someone get some of this and try it with a hacked printer.

We have seen homebrew SLS printers. There’s also OpenSLS that, coincidentally, uses a laser cutter. It wouldn’t be cheap or easy, but being able to turn out metal parts in your garage would be quite the payoff. Be sure to keep us posted on your progress.

Button, Button, Who’s Got The (Pico) Button?

September 20, 2023 by 26 Comments

There is an episode of Ren and Stimpy with a big red “history eraser’ button that must not be pressed. Of course, who can resist the temptation of pressing the unpressable button? The same goes for development boards. If there is a button on there, you want to read it in your code, right? The Raspberry Pi Pico is a bit strange in that regard. The standard one lacks a reset button, but there is a big tantalizing button to reset in bootloader mode. You only use it when you power up, so why not read it in your code? Why not, indeed?

Turns out, that button isn’t what you think it is. It isn’t connected to a normal CPU pin at all. Instead, it connects to the flash memory chip. So does that mean you can’t read it at all? Not exactly. There’s good news, and then there’s bad news.

The Good News

The official Raspberry Pi examples show how to read the button (you have read all the examples, right?). You can convert the flash’s chip-select into an input temporarily and try to figure out if the pin is low, meaning that the button is pushed. Sounds easy, right?

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You’ve Got Mail: Reading Addresses With OCR

September 20, 2023 by 14 Comments

Last time I delivered on this column, I told you about the USPS’ attempts to fully automate a post office. Of course, that’s a bit of a misnomer, since it took 1,500 employees to actually operate the place on a daily basis. Although Project Turnkey in Rhode Island and Project Gateway in California were proving grounds for all kinds of mail sorting and processing equipment, the act of actually reading addresses and routing mail to its final destination still required human intervention and hand coding.

Today, the post office processes hundreds of millions of mail pieces each day using various pieces of equipment. One of those important pieces of equipment is the OCR address reader, which manages to make sense of all kinds of chicken scratch.

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TMD-3: Clever Hall Sensor Hack Leads To Better Turing Demo

September 20, 2023 by 4 Comments

We’ll beat everyone to the punch: yes, actually building a working Turing machine, especially one that uses a Raspberry Pi, is probably something that would have pushed [Alan Turing]’s buttons, and not in a good way. The Turing machine is, above all else, a thought experiment, an abstraction of how a mechanical computing machine could work. Building a working one seems to be missing the point.

Thankfully, [Michael Gardi] has ignored that message three times now, and with good reason: some people just grok abstract concepts better when they can lay their hands on something and manipulate it. His TMD-1 was based on 3D printed tiles with embedded magnets — arranging the tiles on a matrix containing Hall effect sensors programmed the finite state machine, with the “tape” concept represented by a strip of eight servo-controlled flip cards. While TMD-1 worked fine, it had some limitations, which [Mike] quickly remedied with TMD-2, a decidedly more complicated affair that used a Raspberry Pi, a camera, and OpenCV to read an expanded state machine with six symbols and six states, without breaking the budget on all the Hall sensors required.

TMD-3 refines the previous design, eschewing the machine vision approach and returning to the Hall effect roots of the original. But instead of using three sensors per tile, [Mike] determined that one sensor would suffice as long as he could mount the magnet at different depths within each tile. That way, the magnetic field for each symbol could be discerned by a single Hall sensor, greatly reducing complexity and expense. An LCD screen and a Raspberry Pi run a console app that shows the tape status, the state machine, and the state transitions.

[Mike] put a ton of work into this one — there are nineteen project logs — and he includes a lot of useful tips and tricks, like designing PCBs directly in KiCAD before even having a schematic. Of course, with a track record like his, we’d expect nothing less.

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