It’s A Marble Clock, But Not As We Know It

November 6, 2023 by Donald Papp 28 Comments

[Ivan Miranda] is taking a very interesting approach to a marble clock. His design is a huge assembly that uses black and white marbles to create a (sort of) dot matrix display. It’s part kinetic art and part digital clock, all driven by marbles.

Here’s how it works: black and white marbles feed into a big elevator. This elevator lifts marbles to the top of the curved runs that make up the biggest part of the device. The horizontal area at the bottom is where the time is shown, with white and black marbles making up the numerical display. But how to make sure the white marbles and black marbles go in the right order?

The solution to that is simple. Marbles feed into the elevator in an unpredictable order. An array of sensors detects the color of each marble. Solenoids simply eject any marble that isn’t in the right place. For example, if the next marble for track n needs to be white, then simply kick out any black marbles in that position until there’s a white one. Simple, effective, and guarantees plenty of mesmerizing moving parts.

Of course, this means that marble ejection and marble color sensing need to be utterly reliable, and [Ivan] ran into problems with both. Marble ejection took some careful component testing and selection to get the right solenoids. Color sensing (as well as detecting empty spaces) settled on IR-based sensors commonly used in line-following robots.

You can watch the clock in action in the video embedded below just under the page break. We recommend giving it a look, because [Ivan] does a great job of showing all of the little challenges that reared their heads, and how he addressed them. There are still a few things to address, but he expects to have those licked by the next video. In the meantime, [Ivan] asks that if anyone knows a source for high quality glass marbles in bulk, please let him know. Low quality ones vary in size and tend to get stuck.

Marble clocks are great expressions of creativity, especially now that 3D printing is common. We love clock hacks, so if you ever create or run across a good one, let us know about it!

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Reduce The Pi 5’s Power Consumption At A Stroke

November 6, 2023 by Jenny List 18 Comments

The Raspberry Pi 5 is the new wunderkind single-board computer on the block, so new in fact that users are still finding out its quirks. One of those quirks is a surprisingly high power consumption when powered down, despite halting the SoC, it leaves the power on and consumes over a watt even in standby. [Jeff Geerling] has a solution, and it’s a simple config change.

It’s useful to know how to fix this, and we’re indebted to him for finding it, but it’s hardly the most complex of hacks. Where the interest lies is in why the board leaves the lights turned on when nobody’s at home in the first place. It seems that some HATs have an issue when the 3V3 rail shuts down, but the 5V rail doesn’t. The Raspberry Pi foundation took the most compatible route and kept the rails on all the time. Perhaps future OS releases will come up with something more elegant, but at least there *is* a fix.

If you’re new to the Pi 5, you can take a look at our review of a preview model, and see why it’s the closest yet to a usable everyday PC that they’ve produced.

Adding Temperature Sensor Functionality To The CH32V003 MCU

November 5, 2023 by Maya Posch 15 Comments

As cheap as the WCH CH32V003 MCU is, its approximately $0.10 price tag looks far less attractive when you need to start adding on external ICs for missing basic features, such as temperature measurement. This is a feature that’s commonly found on even basic STM32 MCUs. Fear not though, as [eeucalyptus] shows, you can improvise a working solution by finding alternative sources that can act as a thermometer.

Plot of the temperature measurement using the improvised CH32V003 -based temperature sensor. (Credit: eeucalyptus)

The CH32V003 is a low-end, 32-bit RISC-V-based MCU by the China-based Nanjing Qinheng Microelectronics, commonly known abbreviated as ‘WCH’, and featured on Hackaday previously. Although it features a single-core, 48 MHz CPU, its selection of peripherals is fairly basic:

So how do you create an internal temperature sensor using just this? [eeucalyptus] figured that all that’s needed is to measure the drift between two internal clocks – such as the LSI and HSI – as temperatures change and use this to calibrate a temperature graph.

Unfortunately, the LSI isn’t readily accessible, even through the Timer peripheral. This left the AWU (automatic wake-up unit) which also uses the LSI as a clock source. By letting it go to sleep and wake up after N LSI cycles, the AWU enabled indirect access to the LSI.

Internal diagram of the CH32V003 MCU. (Credit: WCH)

After calibrating against room temperature (~22 °C) and ice water (0 °C), a temperature plot was obtained, which could conceivably be somewhat accurate. As [eeucalyptus] warns, this is a kind of calibration that likely differs per MCU, and no attempt to quantify the absolute accuracy of this method has been made yet. Even so, as a crude temperature measurement, it might just be good enough.

What Parts Should You Desolder?

November 5, 2023 by Jenny List 28 Comments

A rite of passage for a young electronics enthusiast used to be collecting an array of surplus boards from whatever could be found, and using them as sources of parts to desolder. It was possible with a bit of work and searching to build all manner of electronic projects without spending much at all. Many hardware hackers know their way around consumer electronics from the decade before their teenage years as a result. Secondhand components can still be used, but the type of components to be found has changed, as well as those needed. [ElectricMonkeyBrain] takes a look, and asks “What should you desolder?”.

As a general rule, he lands on the premise that it’s worth hanging on to the expensive stuff rather than the cheap stuff. Large capacitors, power semiconductors, and inductors aren’t cheap at all, and in the case of the inductors they can yield both ferrite parts and enameled wire for rewinding to suit. We’re surprised that he advocates holding on to electrolytic capacitors as a kit of many values is now pretty cheap, but it’s understandable that if you lack the part and it’s there on a motherboard in front of you, it’s worth desoldering. Finally, he discusses cases, something we’ve been tempted by a few times more than we’d like to mention.

In a world of easy online ordering, it’s useful to be reminded that sometimes there’s still space for salvaged parts, after all, no delivery service is as quick as reaching under your bench for an old ATX power supply to raid. As always though, don’t amass too much of it.

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Hackaday Links: November 5, 2023

November 5, 2023 by Dan Maloney 5 Comments

As I write this, Supercon 2023 is in full swing down in Pasadena — 80 degrees and sunny at the moment, as opposed to 50 and pouring rain where I am, not that I’m bitter. Luckily, though, we can all follow along with the proceedings thanks to the livestreams on the Hackaday channel, which of course will all be available once they’re edited in case you miss anything live. There are a ton of interesting talks coming up, so there’ll be a lot to catch up on when the dust settles. And that won’t be far from now; by the time this post publishes, Supercon will be all but over, which makes it the Thanksgiving dinner of cons — all that work and it’s over in just a few minutes.

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Servo Claw Game Puts Your Muscles To The Test

November 5, 2023 by Kristina Panos 5 Comments

As fun as claw games are, the jaws are always disappointingly weak, and you usually end up with bupkis. What if the jaws were completely within your control? That’s the idea behind [Upside Down Labs]’ muscle-controlled servo claw game.

While electromyography (EMG) is great for identifying neuro-muscular abnormalities and allows for amazing prosthetic limbs to work, it can also be used for fun. As you’ll see in the video after the break, accurate block-stacking (and possible candy-grabbing) depends on teamwork and tensed muscles.

Though the user provides the muscle, the brains behind this operation is an Arduino Uno with a Muscle BioAmp shield stacked on top, which [Upside Down Labs] also created. This shield makes it ridiculously easy to connect EMG sensors and other I²C devices like screens and, well, servo claws. From there, it’s really just a matter of printing the claw, connecting it to a 9g servo, and using an accompanying kit to prepare the skin and connect the muscles to the Arduino. Be sure to check it out in tense block-stacking action after the break.

If you want to listen in on your muscles, look no further than the BioAmp EMG Pill.

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Reducing Poop On Multicolor Prints

November 5, 2023 by Bob Baddeley 25 Comments

While multicolor printing eliminates painting steps and produces vibrant objects, there are two significant downsides; filament consumption and print time. A single-nozzle filament printer needs to switch from one color to another, and doing so involves switching to the other filament and then purging the transition filament that contains a mixture of both colors, before resuming the print with the clean new color.

[teachingtech] tests out a variety of methods for reducing print time and waste. One surprising result was that purging into the infill didn’t result in significant savings, even when the infill was as high as 50%. Things that did have a positive effect included reducing the amount of purge per transition based on light to dark color changes, and printing multiple copies at once so that even though the total amount of waste was the same as a single part, the waste per part was reduced.

All of the tests were with the same model, which had 229 color changes within a small part, so your mileage may vary, but it’s an interesting investigation into some of the deeper settings within the slicer. Reducing filament waste and print time is an admirable goal, and if you make your own extruder, you can turn all of that purge waste into various shades of greenish brownish filament. Continue reading “Reducing Poop On Multicolor Prints” →