Hackaday Links: November 7, 2021

November 7, 2021 by Dan Maloney 3 Comments

More trouble for Hubble this week as the space observatory’s scientific instruments package entered safe mode again. The problems started back on October 25, when the Scientific Instrument Command and Data Handling Unit, or SI C&DH, detect a lack of synchronization messages from the scientific instruments — basically, the cameras and spectrometers that sit at the focus of the telescope. The issue appears to be different from the “payload computer glitch” that was so widely reported back in the summer, but does seem to involve hardware on the SI C&DH. Mission controller took an interesting approach to diagnosing the problem: the dusted off the NICMOS, or Near Infrared Camera and Multi-Object Spectrometer, an instrument that hasn’t been used since 1998. Putting NICMOS back into the loop allowed them to test for loss of synchronization messages without risking the other active instruments. In true hacker fashion, it looks like the fix will be to change the software to deal with the loss of sync messages. We’ll keep you posted.

What happened to the good old days, when truck hijackings were for things like cigarettes and booze? Now it’s graphics cards, at least according to a forum post that announced the theft of a shipment of EVGA GeForce RTX 30-series graphics cards from a delivery truck. The truck was moving the cards from San Francisco to the company’s southern California distribution center. No word as to the modus operandi of the thieves, so it’s not clear if the whole truck was stolen or if the cards “fell off the back.” Either way, EVGA took pains to note that receiving stolen goods is a crime under California law, and that warranties for the stolen cards will not be honored. Given the purpose these cards will likely be used for, we doubt that either of these facts matters much to the thieves.

Remember “Jet Pack Man”? We sure do, from a series of reports by pilots approaching Los Angeles International airport stretching back into 2020 and popping up occasionally. The reports were all similar — an object approximately the size and shape of a human, floating aloft near LAX. Sightings persisted, investigations were launched, but nobody appeared to know where Jet Pack Man came from or what he was flying. But now it appears that the Los Angeles Police may have identified the culprit: one Jack Skellington, whose street name is the Pumpkin King. Or at least a helium balloon version of the gangly creature, which is sure what an LAPD helicopter seems to have captured on video. But color us skeptical here; after all, they spotted the Halloween-themed balloon around the holiday, and it’s pretty easy to imagine that the hapless hero of Halloween Town floated away from someone’s front porch. More to the point, video that was captured at the end of 2020 doesn’t look anything like a Skellington balloon. So much for “case closed.”

Speaking of balloons, here’s perhaps a more productive use for them — lifting a solar observatory up above most of the atmosphere. The Sunrise Solar Observatory is designed to be lifted to about 37 km by a balloon, far enough above the Earth’s ozone layer to allow detailed observation of the Sun’s corona and lower atmosphere down into the UV range of the spectrum. Sunrise has already flown two successful missions in 2009 and 2013 which have netted over 100 scientific papers. The telescope has a one-meter aperture and automatic alignment and stabilization systems to keep it pointed the right way. Sunrise III is scheduled to launch in June 2022, and aims to study the flow of material in the solar atmosphere with an eye to understanding the nature of the Sun’s magnetic field.

And finally, what a difference a few feet can make. Some future Starlink customers are fuming after updating the location on their request for service, only to find the estimated delivery date pushed back a couple of years. Signing up for Starlink satellite service entails dropping a pin on a map to indicate your intended service location, but when Starlink put a new, more precise mapping app on the site, some eager pre-order customers updated their location to more accurately reflect where the dish will be installed. It’s not clear if the actual location of the dish is causing the change in the delivery date, or if just the act of updating an order places you at the bottom of the queue. But the lesson here may be that with geolocation, close enough is close enough.

Unique Seven-Segment Display Relies On FR-4 Fluorescence

October 16, 2021 by Dan Maloney 11 Comments

It’s interesting what you see when you train a black light on everyday objects. We strongly suggest not doing this in a hotel room, but if you shine UV light on, say, a printed circuit board, you might see what [Sam Ettinger] did, which led him to build these cool low-profile seven-segment fluorescent PCB displays.

As it turns out, at least some FR-4 PCBs fluoresce under UV light, giving off a ghostly blue-green glow. Seeing the possibilities, [Sam] designed a PCB with cutouts in the copper and solder mask in the shape of a traditional seven-segment display. The backside of the PCB has pads for UV LEDs and current-limiting resistors, which shine through the board and induce the segments to glow. Through-slots between the segments keep light from one segment from bleeding over into the next; while [Sam] left the slots unfilled, they could easily be filled with solder. The fluorescent property of FR-4, and therefore the brightness and tint of the segments, seems to vary by board thickness and PCB manufacturer, but it looks like most PCBs will show pretty good results.

We’d say the obvious first improvement might be to cover the back of the display with black epoxy, to keep stray light down, and to improve contrast. But they look pretty great just as they are. We can also see how displays with other shapes, like icons and simple symbols. Or maybe even alphanumeric characters — say, haven’t we seen something like that before?

Just How Vulnerable To Accidental Erasure Are EPROMs Anyway?

June 29, 2021 by Dan Maloney 45 Comments

On the scale of things worth worrying about, having to consider whether your EPROMs will be accidentally erased by some stray light in the shop is probably pretty low on the list. Still, losing irreplaceable data can make for a bad day, so it might just pay to know what your risks really are.

To address this question, [Adrian] set out to test just how susceptible to accidental erasure some common EPROM chips are. An EPROM, or “erasable programmable read-only memory”, is a non-volatile memory chip that can be programmed electrically and then erased optically, by exposing the die inside the chip to light at a specific wavelength, usually in a special chip erasing tool. But erasure can also happen in daylight (even if it takes a few weeks), so [Adrian] cooked up an experiment to see what the risk really is.

He exposed a selection of EPROMs with known contents to UV and checked their contents. Three of the chips had a simple paper or foil label applied, while one had its quartz window exposed to the UV. As expected, the unprotected chip was erased in just 30 minutes. The covered chips, though, all survived that onslaught, and much more — up to 780 minutes of continuous exposure.

So rest easy — it seems that even a simple paper label is enough to protect your precious retro EPROMs. It’s a good data point, and hats off to [Adrian] for taking a look at this. But now we can’t help but wonder: what would a little sunscreen applied to the quartz window do to erasability? Sounds like a fun experiment, too.

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Persistent Displays With UV Light

May 24, 2021 by Jenny List 52 Comments

This year’s Hackaday Prize has “Rethink Displays” as one of its first theme, and [Tucker Shannon] has given us his best shot on that subject with a set of impressive displays that “write” on glow-in-the-dark material using ultra-violet light. These materials glow for a while after UV illumination, so moving a light source like a UV LED over the surface draws glowing text or simple graphics which can be readily consumed.

One of the examples this a clock we were first smitten with back in 2018. It is a rather attractive 3D-printed affair with those servos mounted below the screen that moves a UV LED through a pair of linkages. Other offerings that play on the same UV stylus medium include a laser on an az-el mount controlled by a Raspberry Pi Zero. It’s a neat idea very effectively done, and we can see it has a lot of potential.

But the most impressively advanced so far is the model shown in the image at the top of the article and the demo video at the bottom. A loop of phosphorescent material is the display surface itself. This one moves that loop with two rollers to make up the X axis, and moves the UV source up and down for the Y axis. As with all of these designs, whatever is written will soon fade, leaving the surface ready for the next bit of information.

Interested in this project and think you could do a display of your own? The Hackaday Prize 2021 is live, and we’d love to see you enter it!

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Cocktail Of Chemicals Makes This Blueprint Camera Unique

May 24, 2021 by Dan Maloney 18 Comments

When you’re looking at blueprints today, chances are pretty good that what you’re seeing is anything but blue. Most building plans, diagrams of civil engineering projects, and even design documents for consumer products never even make it to paper, let alone get rendered in old-fashioned blue-and-white like large-format prints used to produced. And we think that’s a bit of a shame.

Luckily, [Brian Haidet] longs for those days as well, so much so that he built this large-format cyanotype camera to create photographs the old-fashioned way. Naturally, this is one of those projects where expectations must be properly scaled before starting; after all, there’s a reason we don’t go around taking pictures with paper soaked in a brew of toxic chemicals. Undaunted by the chemistry, [Brian] began his journey with simple contact prints, with Sharpie-marked transparency film masking the photosensitive paper, made from potassium ferricyanide, ammonium dichromate, and ammonium iron (III) oxalate, from the UV rays of the sun. The reaction creates the deep, rich pigment Prussian Blue, contrasting nicely with the white paper once the unexposed solution is washed away.

[Brian] wanted to go beyond simple contact prints, though, and the ridiculously large camera seen in the video below is the result. It’s just a more-or-less-lightproof box with a lens on one end and a sheet of sensitized paper at the other. The effective ISO of the “film” is incredibly slow, leading to problematically long exposure times. Coupled with the distortion caused by the lens, the images are — well, let’s just say unique. They’ve got a ghostly quality for sure, and there’s a lot to be said for that Prussian Blue color.

We’ve seen cyanotype chemistry used with UV lasers before, and large-format cameras using the collodion process. And we wonder if [Brian]’s long-exposure process might be better suited to solargraphy.

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Laser Blasts Out High-Quality PCBs

January 11, 2021 by Dan Maloney 53 Comments

With how cheap and how fast custom PCBs have gotten, it almost doesn’t make sense to roll your own anymore, especially when you factor in the messy etching steps and the less than stellar results. That’s not the only way to create a PCB, of course, and if you happen to have access to a 20-Watt fiber laser, you can get some fantastic homemade PCBs that are hard to tell from commercial boards.

Lucikly, [Saulius Lukse] of Kurokesu fame has just such a laser on hand, and with a well-tuned toolchain and a few compromises, he’s able to turn out 0.1-mm pitch PCBs in 30 minutes. The compromises include single-sided boards and no through-holes, but that should still allow for a lot of different useful designs. The process starts with Gerbers going through FlatCAM and then getting imported into EZCAD for the laser. There’s a fair bit of manual tweaking before the laser starts burning away the copper between the traces, which took about 20 passes for 0.035-mm foil on FR4. We have to admit that watching the cutting proceed in the video below is pretty cool.

Once the traces are cut, UV-curable solder resist is applied to the whole board. After curing, the board goes back to the laser for another pass to expose the pads. A final few passes with the laser turned up to 11 cuts the finished board free. We wonder why the laser isn’t used to drill holes; we understand that vias would be hard to connect to the other side, but it seems like through-hole components could be supported. Maybe that’s where [Saulius] is headed with this eventually, since there are traces that terminate in what appears to be via pads.

Whatever the goal, these boards are really slick. We usually see lasers used to remove resist prior to traditional etching, so this is a nice change.

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A UV Curing Wand For Everyone

December 6, 2020 by Matthew Carlson 12 Comments

The average person’s experience with an ultraviolet (UV) wand is getting a cavity at the dentist. However, anyone with a resin-based 3d printer knows how important a UV curing system is. Often times some spots on a print need a little bit of extra UV to firm up. [Mile] has set out to create an open-source UV curing wand named Photon that is cost-effective and easy to build.

What’s interesting here is that there are dozens if not hundreds of UV curing systems ranging from $5 LED flashlights to larger industrial flood systems. [Mile] dives right in and shows the trade-offs that those cheaper modules are making as well as what the commercial systems are doing that he isn’t. [Mile’s] Photon wand tries to be energy efficient with more irradiated power while staying at a lower cost. This is done by carefully selecting the CSP LEDs instead of traditional wire-bonded and making sure the light source is properly focused and cooled. From the clean PCB and slick case, it is quite clear that [Mile] has gone the extra step to make this production-friendly. Since there are two industry-standard wavelengths that resins cure at (364nm and 405nm), the LED modules in Photon are user-replaceable.

What we love about this project is looking past what is readily available and diving deep. First understanding the drawbacks and limitations of what is there, then setting a goal and pushing through to something different. This isn’t the first UV curing tool we’ve seen recently, so it seems there is a clear need for something better that’s what is out there today.

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