Giving Solar Power’s Mortal Enemies A Dusting Without Wasting Water

August 16, 2023 by Maya Posch 28 Comments

A prerequisite for photovoltaic (PV) and concentrated solar power (CSP) technologies to work efficiently is as direct an exposure to the electromagnetic radiation from the sun as possible. Since dust and similar particulates are excellent at blocking the parts of the EM spectrum that determine their efficiency, keeping the panels and mirrors free from the build-up of dust, lichen, bird droppings and other perks of planetary life is a daily task for solar farm operators. Generally cleaning the panels and mirrors involves having trucks drive around with a large water tank to pressure wash the dirt off, but the use of so much water is problematic in many regions.

Keeping PV panels clean is also a consideration on other planets than Earth. So far multiple Mars rovers and landers have found their demise at the hands of Martian dust after a layer covered their PV panels, and Moon dust (lunar regolith) is little better. Despite repeated suggestions by the peanut gallery to install wipers, blowers or similar dust removal techniques, keeping particulates from sticking to a surface is not as easy an engineering challenge as it may seem, even before considering details such as the scaling issues between a singular robot on Mars versus millions of panels and mirrors on Earth.

There has been research into the use of the electrostatic effect to repel dust, but is there a method that can keep both solar-powered robots on Mars and solar farms on Earth clean and sparkling, rather than soiled and dark?

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Food Safe 3D Printing: A Study

September 5, 2022 by Dave Rowntree 43 Comments

[Matt Thomas] wanted to answer the question of whether 3D printed structures can be food-safe or even medical-safe, since there is an awful lot of opinion out there but not a lot of actual science about the subject. As a mechanical engineer who dabbles in medical technical matters, he designed as series of tests using a wide range of nasty-sounding pathogens, to find once and for all what works and what does not.

One common argument sprung up from the maker movement response to COVID-19, 3D printed masks and visors. Many of us (this scribe included) printed many thousands of visor frames and ear protectors, using the armies of 3D printers we had available, then distributed them to nursing homes and doctors’ surgeries, and anywhere else that couldn’t get ‘proper’ medical-grade items.

There was much opinion about the risks associated with contamination of such 3D printed structures, due to the allegedly porous nature of the prints. [Matt] has shown with some SEM imaging, that a typical 3D print does not have any detectable porosity, and that the grooves due to the layer lines are so positively huge compared to your average bacterium, as to also be irrelevant.

Cutting to the chase, [Matt] shows that ordinary dish soap and water are totally sufficient to remove 90% or more of all of the pathogens he tested, and that using a mix of culturing swap samples as well as protein detection, that 3D printed parts could be cleaned close to medical standards, let alone those of food handling. Even those pesky biofilms could be quickly dispatched with either a quick rinse in bleach-water or a scrub with baking soda. Does this article clear this up finally? Only you can decide!

We’ve obviously covered the subject of 3D printing masks a fair bit, but it’s not all about PPA, sometimes ventilators need some 3D printing love too. Prusa did some work on the subject of food safety, looking specifically at post-processing for 3D prints, and produced some interesting results.

Thanks to [Keith] for the tip!

Giving Vintage Synths New Life In A Potentiometer Cleaning Showdown

January 19, 2022 by Maya Posch 24 Comments

As anyone who has ever owned a piece of older equipment that has a potentiometer in it can attest to, these mechanical components do need their regular cleaning ritual. Whether it’s volume knobs on a receiver or faders on a mixer, over time they get crackly, scratchy and generally imprecise due to the oxidation and gunk that tends to gather inside them.

This is your potentiometer caked with gunk.

In this blast from the past, [Keith Murray] shows a few ways in which fader-style potentiometers can be cleaned, and how well each cleaning method works by testing the smoothness of the transition over time with an oscilloscope. It’s enlightening to see just how terrible the performance of a grimed-up fader is, and how little a blast of compressed air helped. Contact cleaner works much better, but it’s essential to get all of the loosened bits of gunk out of the fader regardless.

In the end, a soak in isopropyl alcohol (IPA), as well as a full disassembly followed by manual cleaning were the only ones to get the fader performance back to that of a new one. Using contact cleaner followed by blasting the fader out with compressed air seems to be an acceptable trade-off to avoid disassembly, however.

What is your preferred way to clean potentiometers to keep that vintage (audio) gear in peak condition? Let us know in the comments below.

Thanks, [Grant Freese], for the tip!

A robotic turret shooting plastic balls at a man

Automated Turret Keeps Dorm Clean, RoboCop Style

December 14, 2021 by Robin Kearey 17 Comments

Students’ dorm rooms are not generally known to be the most orderly of places. Whether it’s mountains of dishes in the sink, piles of clothes waiting to be washed, or random bits and bobs strewn across the hallway, cleaning up is pretty low on the agenda for many dorm dwellers.

[Luis Marx] seems to have invented a useful solution to his (or his roommates’) sloppiness: a robotic turret that opens fire on anyone who leaves items unattended (video, in German, embedded below). This system uses a set of “clutter sensors” that can be placed in strategic locations around the house and will detect stray objects using ultrasonic sensors. If any are found, the main system is alerted through WiFi. The turret will then search for any persons in its vicinity and start shooting them with little plastic balls.

The turret in question is a beautifully-designed piece of kit made from 3D printed parts and controlled by an ESP32. It can swivel around its axis and tilt up and down using two servos, while its firing mechanism is driven by a DC motor. It tracks its target thanks to a camera-based object sensor that can recognize humans. The whole thing gives us a bit of a RoboCop vibe; we’d half expect it to shout Pick up those clothes. You have twenty seconds to comply.

While this might not be the definitive solution to messy dorm rooms, we like the creative thinking behind it. We’ve seen auto-targeting turrets before, but not in household applications like this. Of course there are plenty of other robots that can help you with domestic tasks.

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An Atari 800 XL, partially covered in battery residue

Massive Cleaning Effort Saves Acid-Drenched Atari

September 12, 2021 by Robin Kearey 13 Comments

Anyone who’s ever had to deal with the aftermath of a leaking battery knows how much damage such a failure can cause. Degrading batteries leak corrosive chemicals that eat away PCB traces, clog up connectors and generally leave everything looking nasty. Getting your gadget working again usually calls for lots of scrubbing, followed by patiently tracing suspect connections and restoring any broken ones.

We doubt, however, that anyone has ever gone through as much effort as [Lee Smith] has on his Atari 800 XL. This example was listed on eBay in a severely damaged state, having been stored under an entire box of leaking batteries. [Lee] put in a bid and, to his own bemusement, won the auction. He was now the proud owner of a classic gaming machine which was covered in a thick brown crust of battery residue.

A first inspection showed that the damage was more than skin-deep: even inside the computer’s case it was one big mess of crusty brown junk. [Lee] first spent several hours on the plastic case, using different cleaning agents and an ultrasonic bath, and managed to get the case almost spotless again. The keyboard presented a larger challenge however: not only did it require thorough cleaning of every single switch and keycap, the keyboard’s matrix on the PCB had several connections missing, which had to be restored using bodge wires.

With the keyboard working again, [Lee] turned to the mainboard. This turned out to be an even greater challenge, with several components (including a few custom chips) damaged beyond repair. With the help of a few eBay replacements parts and (again) countless hours of scrubbing, the mainboard started to look healthy again. After a few tests, [Lee] felt confident enough to hook up the entire system and turn it on. And his efforts had paid off: the battered Atari dutifully displayed its BASIC prompt, ready for its second lease of life.

We’ve seen before what kind of damage a leaking battery can do to an Amiga, or faulty caps to an Xbox. But both of these seem minor inconveniences compared to what happened to this poor Atari. Thanks to [Simon] for the tip.

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DIY Grout Cleaning Machine Does A Good Job

September 24, 2020 by Lewin Day 25 Comments

Cleaning tiled floors can be a drag. Getting the tiles themselves clean is bad enough, but often dealing with the grouted joints in between requires more elbow grease and attention to detail. It’s a tedious chore, and thus one ripe for improvement. [Elite Worm]’s cleaning machine is an excellent solution to the problem.

The machine is built entirely from scratch, using primarily 3D printed components. A fluid tank is fitted to the chassis, along with a custom 3D-printed pump run by a DC motor, to deliver cleaning product where its needed. A large DC motor is then used to spin a nylon brush which gets deep in the tile grooves to clean out the grime. The chassis is then fitted with rollers to allow it to glide along the floor. Finally, a handle is fitted which allows the user to push the tool along, with switches to turn on the spinning brush and dispense cleaning fluid.

It’s a great tool, and one which eliminates hours of scrubbing on hands and knees. We’re sure the time investment in the build will pay off before long. We’ve seen other tricky cleaning hacks before, too. Video after the break.

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Cheap Alternative Solvents For PCB Cleaning

April 29, 2020 by Dan Maloney 82 Comments

If you’re in the habit of using isopropyl alcohol to clean your PCBs after soldering, you probably have a nice big jug of the stuff stashed away. If you don’t, you’re probably out of luck, since the COVID-19 pandemic has pretty much cleared IPA out of the retail market. But don’t fret: depending on where you live, alternative PCB cleaning solutions may be as close as your nearest auto parts store.

[Steven]’s search for a cheaper and perhaps more readily available substitute for his usual dedicated flux cleaner lead him to try automotive brake cleaner on a few test boards. He suspected that they might contain acetone, which is prone to yield unfortunate results with solder resist and silkscreen on PCBs, so some tests were in order. The brand he tried was Normfest Bremsenreiniger MC-1, a German brand that according to its Safety Data Sheet contains only hydrocarbons like alkanes, butane, and propane. It did a fine job cleaning all but the crustiest rosin flux without collateral damage.

In the video below, [Steven] goes through a few more brands with similar results, and we were encouraged enough by his results to check brake cleaners made for the US market. Alas, almost all of the cheap and readily available aerosols have acetone as the principle ingredient, mixed in with methanol, ethanol, and assorted ingredients that together will probably make for a bad day. About the only US-sold brand without acetone that we could find was Keller-Heartt, which lists only naptha and ethanol on its SDS. There may be others, but make sure you test whatever you find.

Aerosol solvents aren’t the only way to clean a PCB, of course. Ultrasonic cleaners do a great job, and as [Steven] discovered, they’re generally safe for most components.

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