The Short Workbench

March 13, 2024 by Al Williams 36 Comments

Imagine an electronics lab. If you grew up in the age of tubes, you might envision a room full of heavy large equipment. Even if you grew up in the latter part of the last century, your idea might be a fairly large workbench with giant boxes full of blinking lights. These days, you can do everything in one little box connected to a PC. Somehow, though, it doesn’t quite feel right. Besides, you might be using your computer for something else.

I’m fortunate in that I have a good-sized workspace in a separate building. My main bench has an oscilloscope, several power supplies, a function generator, a bench meter, and at least two counters. But I also have an office in the house, and sometimes I just want to do something there, but I don’t have a lot of space. I finally found a very workable solution that fits on a credenza and takes just around 14 inches of linear space.

How?

How can I pack the whole thing in 14 inches? The trick is to use only two boxes, but they need to be devices that can do a lot. The latest generation of oscilloscopes are quite small. My scope of choice is a Rigol DHO900, although there are other similar-sized scopes out there.

If you’ve only seen these in pictures, it is hard to realize how much smaller they are than the usual scopes. They should put a banana in the pictures for scale. The scope is about 10.5″ wide (265 mm and change). It is also razor thin: 3″ or 77 mm. For comparison, that’s about an inch and a half narrower and nearly half the width of a DS1052E, which has a smaller screen and only two channels.

If you get the scope tricked out, you’ve just crammed a bunch of features into that small space. Of course, you have a scope and a spectrum analyzer. You can use the thing as a voltmeter, but it isn’t the primary meter on the bench. If you spend a few extra dollars, you can also get a function generator and logic analyzer built-in. Tip: the scope doesn’t come with the logic analyzer probes, and they are pricey. However, you can find clones of them in the usual places that are very inexpensive and work fine.

There are plenty of reviews of this and similar scopes around, so I won’t talk anymore about it. The biggest problem is where to park all the probes. Continue reading “The Short Workbench” →

Custom Library Rescues Good LoRa Hardware From Bad Firmware

March 13, 2024 by Dan Maloney 17 Comments

The range of hardware that comes on some dev boards these days is truly staggering. Those little LoRa boards are a prime example — ESP32 with WiFi and Bluetooth, a transceiver that covers a big chunk of the UHF band, and niceties like OLED displays and plenty of GPIO. But the firmware and docs? Well, if you can’t say something nice, don’t say anything at all. Or better yet, just roll your own.

Of course that doesn’t hold true for all the LoRa dev boards on the market, but [Rop] certainly found it to be the case for the Heltec HTIT-WB32LA. This board has all the bells and whistles and would be perfect for LoraWAN and Meshtastic applications, but it needed a little help getting it over the line. [Rop]’s contribution to this end is pretty comprehensive and is based on his fork of the RadioLib library, which incorporates a library that greatly reduces wear on the ESP32’s flash memory. In addition to full radio support, the library supports all the hardware on the board from the pushbutton to the display, power management and battery charging, and of course the blinkenlights.

[Jop] includes quite a few example applications, from the bare minimum needed to get the board spun up to a full-blown spectrum analyzer. It’s a nice piece of work, and a great give-back to the LoRa community. And if you want to put one of these modules to work, you’re certainly in the right place. We’ve got everything from LoRaWAN networks to the magic of Meshtastic, so take your pick and get hacking.

A dress is shown in three shapes: the original, a slightly-heated A-line version, and a close-fitting body con version.

4D Knit Dress Skirts Waste

March 13, 2024 by Kristina Panos 21 Comments

Regular 2D sewing of anything is inherently wasteful. You can align the pattern pieces however you want, but there’s going to be wasted everything — thread, fabric, and interfacing — whether you get it right the first time or not. Never mind the fact that people tend to create a muslin (prototype) first using inexpensive fabric (like muslin) for the purposes of getting the fit right.

A few examples of the lines than can be created.

The MIT Self-Assembly Lab x Ministry of Supply have come up with a 4D garment construction technique that minimizes waste while being pretty darn cool at the same time. They’ve created a knit dress that combines several techniques and tools, including heat-activated yarns, computerized knitting, and 6-axis robotic activation. The result is a dress that can be permanently molded to fit the body however and wherever you want, using a heat gun mounted on a 6-axis robotic arm.

As far as we can tell, a finished dress does not come off of the machine in the short demo video after the break. It looks like it still has to be sewn together, which creates some potential for waste, but absolutely nothing like conventional methods.

This is probably the coolest dress we’ve seen since the one covered in LCD panels.

Continue reading “4D Knit Dress Skirts Waste” →

Randomly Move Marionette With Steel Balls And Geneva Drives

March 12, 2024 by Maya Posch 17 Comments

Over the years we have seen many marble machines, but this one on the [Karakuri channel] (hit CC for subtitles) on YouTube is somewhat special, as it uses Geneva drives to turn the motion of the steel balls going around the circuit into random movement of a marionette. The Geneva drive type of gear mechanism normally converts a constant rotary motion into intermittent rotary motion by having a singular pin on the first wheel drive the second wheel. In the demonstrated mechanism, however, the pin is replaced by the steel balls, which are only intermittently and randomly present because of how each steel ball picks one of four paths, one towards each Geneva drive.

As a result of this, the motion of the marionette’s appendages – attached to the red wheel – is random. The only powered element of the (mostly 3D printed) system is the drive mechanism that carries the steel balls up again and keeps the primary wheels on the Geneva drives rotating. We have to give the creator pops for what is both an interesting art piece and a demonstration of how to creatively use this somewhat unusual gear mechanism to introduce randomness without a lot of complexity.

Thanks to [MrTrick] for the tip.

Continue reading “Randomly Move Marionette With Steel Balls And Geneva Drives” →

An Optical Computer Architecture

March 12, 2024 by Al Williams 14 Comments

We always hear that future computers will use optical technology. But what will that look like for a general-purpose computer? German researchers explain it in a recent scientific paper. Although the DOC-II used optical processing, it did use some conventional electronics. The question is, how can you construct a general computer that uses only optical technology?

The paper outlines “Miller’s criteria” for practical optical logic gates. In particular, any optical scheme must provide outputs suitable for introduction to another gate’s inputs and also support fan out of one output to multiple inputs. It is also desirable that each stage does not propagate signal degradation and isolate its outputs from its inputs. The final two criteria note that practical systems don’t depend on loss for information representation since this isn’t reliable across paths, and, similarly, the gates should require high-precision adjustment to work correctly.

The paper also identifies many misconceptions about new computing devices. For example, they assert that while general-purpose desktop-class CPUs today contain billions of devices, use a minimum of 32-bits of data path, and contain RAM, this isn’t necessarily true for CPUs that use different technology. If that seems hard to believe, they make their case throughout the paper. We can’t remember the last scientific paper we read that literally posed the question, “Will it run Doom?” But this paper does actually propose this as a canonical question.

Continue reading “An Optical Computer Architecture” →

A Kyria split keyboard and wrist rests on a stand made of LEGO.

LEGO Keyboard Stand Fits Just Right

March 12, 2024 by Kristina Panos 3 Comments

Split keyboards are great for many reasons, but mostly because you can place the halves as far apart as you want and really give your arms and shoulders the room they need. [Jason Cox] hit the nail on the head, though: add in a couple of palm rests, and you now have four things that will potentially shift and drift out of place on your desk or keyboard tray. It was such a problem that [Jason] hardly ever used his Kyria. That is, until he built a stand out of LEGO to hold everything.

[Jason] was using a pair of Manfrotto pocket tripods to tent the keyboard, and those held their position surprisingly well, even though he tweaked them here and there over time. Ultimately, [Jason] knew he wanted the answer to be something customizable. And what’s more customizable than LEGO?

About $60 worth of new white bricks and plates later, [Jason] got to work, spending an evening building the thing. He ended up using a few bricks to hold the keyboard in place on the plate, and it worked perfectly.

Of course, he didn’t get the whole contraption exactly how he wanted it the first time, but tweaking builds is half the fun, right? After a while, [Jason] figured out he could rebuild the part that connects the two keyboard halves to go around a plastic piece at the back of the keyboard tray, which holds the whole thing in place. The end result? Wonderful. The Kyria stays in place, and now [Jason] is using it way more than before.

You know LEGO is versatile, but did you know you can use it to build a hydroelectric dam?

Via reddit

Playing Audio On The Pi Pico With No DAC To Speak Of

March 12, 2024 by Lewin Day 24 Comments

Normally, if you want to play music or other audio on a microcontroller, you need to get yourself a DAC. Or at least, that’s the easiest way to go about it and the one most likely to get you good, intelligible audio. You don’t have to go that way, though, as [antirez] demonstrates.

[antirez] decided to do this with a Pi Pico, but it’s applicable to other microcontrollers too. It’s all done with a single pin and a PWM output. The PWM output is set to a very high frequency beyond human hearing. In this case, it was 100 KHz. Then, the duty cycle of the PWM is changed to essentially output various average voltage levels at the pin. Vary the output voltage as per your desired sound file by using each sample to vary the duty cycle of the PWM. Voila! You can output whatever sound you want on that pin! [antirez] steps through the basics of doing this, including processing simple WAV files into a raw format that can be dumped into MicroPython code.

There’s no sound sample on the project page, and we’d have to assume it sounds pretty crunchy when hooked up to a speaker. And yet, it could prove a useful technique if you’re designing your own audio greeting cards or something, so keep that in mind!