Pining For A De-Googled Smartphone

September 2, 2021 by Bryan Cockfield 88 Comments

Last summer in the first swings of the global pandemic, sitting at home finally able to tackle some of my electronics projects now that I wasn’t wasting three hours a day commuting to a cubicle farm, I found myself ordering a new smartphone. Not the latest Samsung or Apple offering with their boring, predictable UIs, though. This was the Linux-only PinePhone, which lacks the standard Android interface plastered over an otherwise deeply hidden Linux kernel.

As a bit of a digital privacy nut, the lack of Google software on this phone seemed intriguing as well, and although there were plenty of warnings that this was a phone still in its development stages it seemed like I might be able to overcome any obstacles and actually use the device for daily use. What followed, though, was a challenging year of poking, prodding, and tinkering before it got to the point where it can finally replace an average Android smartphone and its Google-based spyware with something that suits my privacy-centered requirements, even if I do admittedly have to sacrifice some functionality.

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Ferrofluid Display Gets New, Better Driver Circuitry

August 26, 2021 by Jim Heaney 14 Comments

In 2019 [Simen] and [Amud], two students from the University of Oslo, set out to design a unique open-source display. The result was Fetch, a display that uses electromagnets to suspend ferrofluid on 252 “pixels” across the screen. After some delays due to COVID, they have recently unveiled version 2.0 of the display on their project’s page.

While the duo managed to overcome the mechanical challenges associated with using ferrofluids fairly easily, they were quickly bottlenecked by their electronics. The use of electromagnets holding up a liquid presented a unique challenge; the magnets could not be switched off, even for a millisecond, or else the “pixel” would fall down to the bottom of the screen. That immediately ruled out any sort of multiplexing and meant everything would have to be driven in parallel. As if that wasn’t already difficult enough to work around, the effect of having multiple electromagnets activated next to each other would change how the ferrofluid flows. This meant that the strength of each electromagnet would have to be adjusted based on what is currently being displayed, rather than just being on or off.

The mess of connections were not helped with the layout of the old driver boards shown here. The new design puts the connections closer to each individual electromagnet.

All of this, paired with other overhead like generating pulse-width modulation for the inputs, was just too much for a single microcontroller to handle. So, the pair set out to design a better version of their electronics that would offload a lot of the hard work. At the same time, they decided a bit of mechanical optimization was in order; they redesigned the boards to be longer and thinner, allowing them to fit cleanly behind the row of electromagnets they controlled.

The new boards feature a PCA9685 IC, which allows for the control of up to 16 channels of 12-bit PWM over i2C, perfect for the size of the display. Since this IC can’t source enough current to drive the electromagnets, it was paired with a ULN2803 Darlington Transistor Array, capable of delivering up to 500mA to each electromagnet.

With prototypes in hand (and a few bodge wires here and there), [Simen] and [Amud] had the new driver boards running beautifully, displaying text in a mesmerizing way that no ordinary display could match. Watch the video after the break for a demonstration of the new controllers in action, as well as a deeper dive into the process of developing them.

Want to learn more? Check out our previous article about Fetch! Or if you’re looking for another cool way to use ferrofluids, how about making it dance in a custom speaker!

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A Whole Lot Of Stepper Motors Make The Most Graceful 7-Segment Displays

August 11, 2021 by Mike Szczys 23 Comments

Over the years we’ve seen many takes on the 7-segment display. Among the most interesting are the mechanical versions of what is most often an LED-based item. This week’s offering is from [John Burd], who published a very odd video showing off the clock he made. But look beyond YouTuber antics and you’ll see the stepper motors he used to turn the segments are dripping with graceful beauty. (Video, embedded below.)

Okay if you want to hear [Charlie Sheen] say “Raspberry P-eye”, this is the video for you. [John] used Cameo to get the (former?) star to talk about what was used to build the clock. Like we said, the video is weird. Let’s embrace that right away and then never talk about it again.

The thing is, the build is such a good idea. [John] went with some stepper motors you can source relatively cheaply from Ali Express and the like. Typically they’re around a buck or two each and have a couple of wings for screw mounting brackets. This builds on the segment displays we’ve seen that use hobby servos by allowing you finer control of how the segments move. Sure, the 90° rotation isn’t all that much to work with, but it will be much smoother and you can get fancy with the kinematics you choose. The only place we see room for improvement is the alignment of the segments when they are turned “off” as you can see the center segment in the video thumbnail below is not quite level. Maybe a linkage mechanism would allow for a hing mechanism that aligns more accurately while hiding the servos themselves behind the mounting plate? It’s in your hands now!

In the demo video you’ll also find some interesting test rigs built to proof out the project. One just endurance tests the mechanism, but the other two envision water-actuated segments. One pumps a hollow, transparent segment with colored liquid. The other tried to use water droplets sprayed in the air to illuminate laser segments. Both are cool and we’d like to see more of the oddball approaches which remind us of the ferrofluid clock.

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Astronomic Patio Light Timer

June 30, 2021 by Chris Lott 21 Comments

Not satisfied with the handheld remote control for his outdoor patio lights, [timabram] decided to build an automatic timer using an ESP8266. He’s using a set of string lights from Costco, but as you dig into his project you’ll see the method he uses can be applied to almost any set of lights that have a remote.

He does this by connecting GPIO pins from the ESP8266 GPIO into the remote control in order to simulate a user pressing the button. Both boards are packaged together in a 3D-printed enclosure that utilizes the front portion of the remote control, so that manual operation is still possible.

His firmware gets the date and time from an NTP server, and then makes an API call to an online service that returns the local sunrise and sunset times for a specific location. He tries to minimize the power consumption by experimenting with different intervals to wakeup from deep sleep and ping the time server. But in the end, he realizes the RF remote control carries quite some distance, and installed the unit inside a closet where it could be powered by adaptors connected to the mains.

We wondered how the remote control knows if the lights are on or off, and [timabram] notes this is a shortcoming which could be addressed in a future version. If you’ve ever seen a mechanical version of an astronomic timer switch, packed full of gears and dials and setting pins, you can really appreciate a no-moving-parts solutions like this project. If you want to make one that doesn’t use the internet, check out this Arduino-based solution that we wrote about back in 2013.

The Other First Computer: Konrad Zuse And The Z3

June 16, 2021 by Chris Lott 43 Comments

Bavarian Alps, Dec. 1945:

Since 1935, Berlin engineer Konrad Zuse has spent his entire career developing a series of automatic calculators, the first of their kind in the world: the Z1, Z2, Z3, S1, S2, and Z4. He accomplished this with a motley group of engineers, technicians, and mathematicians who were operating against all odds. With all the hardships and shortages of war and the indifference of their peers, the fact that they succeeded at all is a testament to their dedication and resourcefulness. And with the end of the war, more hardships have been piling on.

Two years ago, during the Battle of Berlin, bombers completely destroyed the Zuse family home and adjacent workshops on the Methfesselstraße, where they performed research and fabrication. All of the calculators, engineering drawings, and notes were lost in the rubble, save for the new Z4 nearing completion across the canal in another workshop on Oranienstraße. In the midst of all this, Zuse married in January of this year, but was immediately plunged into another crisis when the largest Allied air raid of the war destroyed the Oranienstraße workshop in February. They managed to rescue the Z4 from the basement, and miraculously arranged for it to be shipped out of the Berlin. Zuse, his family, and colleagues followed soon thereafter. Here and there along the escape route, they managed to complete the final assembly and testing of the Z4 — even giving a demonstration to the Aerodynamics Research Institute in Göttingen.

On arrival here in the Bavarian Alps, Zuse found a ragtag collection of refugees, including Dr Werner Von Braun and a team of 100 rocket scientists from Peenemünde. While everyone here is struggling just to stay alive and find food and shelter, Zuse is further worried with keeping his invention safe from prying eyes. Tensions have risen further upon circulation of a rumor that an SS leader, after three bottles of Cognac, let slip that his troops aren’t here to protect the scientists but to kill them all if the Americans or French approach.

In the midst of all this madness, Zuse and his wife Gisela welcomed a baby boy, and have taken up residence in a Hinterstein farmhouse. Zuse spends his time working on something called a Plankalkül, explaining that it is a mathematical language to allow people to communicate with these new machines. His other hobby is making woodblocks of the local scenery, and he plans to start a company to sell his devices once the economy recovers. There is no doubt that Konrad Zuse will soon be famous and known around the world as the father of automatic computers. Continue reading “The Other First Computer: Konrad Zuse And The Z3” →

Old Textbooks Galore

June 4, 2021 by Chris Lott 41 Comments

This collection of public domain books proclaims to not be about survival, but for survivors. It is a extensive collection of text books, manuals, etc., in over 150 categories from Accounting to Woodworking. Because of the copyright duration laws, most are around one hundred years old.

You might not want to have your appendix removed by someone who has only learned surgery from reading Dr John Sluss’s 1908 tome, “Emergency Surgery for the General Practitioner, with 584 illustrations, some of which are printed in colors“. But some knowledge is timeless. And much is of historical interest as well, helping us get a better appreciation of what bodies of knowledge people had in the beginning of the last century. There are books on farming, forging and casting, steam engines, clockmaking, telegraph and telephone, and even back issues of Scientific American and 73 magazines, just to name a few.

Here’s a random sampling of a few illustrations from electronics-related books.

High speed electrons from “Inside the Vacuum Tube” by John F. Rider, 1945, a relatively modern book from this collection. This book alone is worth downloading just to see the excellent illustrations. Mr Rider wrote so many technical books that he formed his own publishing company.

Using triangles from “Mechanical Drawing, Prepared for the Students of the Massachusetts Institute of Technology” by Linus Faunce, 1898.

The Weidemann system of wiring lamps, from “Electric-Wiring, Diagrams and Switchboards” by Newton Harrison E.E., published in 1906, complete with “one hundred and five illustrations showing the principles and technics of the art of wiring”. This system employed equal lengths of wires between each lamp in a (failed) attempt to make the voltage drop the same for each bulb.

Do you have any timeless reference or text books you like to use? Let us know down below in the comments. And thanks to [David Gustafik] for the tip.

Transparent Hard Drive Gives Peek At The Platters

May 19, 2021 by Tom Nardi 29 Comments

Solid-state drives (SSDs) are all the rage these days, and for good reason. But that doesn’t mean the era of the spinning disk is over, as traditional mechanical hard drives still offer a compelling value for mass storage applications where access times aren’t as critical. But the components inside these “slow” mechanical drives are still moving at incredible speeds, which [The Developer Guy] has nicely illustrated with his transparent hard drive.

Now unfortunately the technology to produce a fully transparent hard drive doesn’t exist, but laser cutting a new top plate out of acrylic is certainly within the means of the average hacker. The process is pretty straightforward: cut out a piece of clear plastic in the same shape and size as the drive’s original lid, put the appropriate mounting holes in it, and find some longer screws to accommodate the increased thickness.

Because this is just for a demonstration, [The Developer Guy] doesn’t need to worry too much about dust or debris getting on the platters; but we should note that performing this kind of modification on a drive you intend on actually using would be a bad idea unless you’ve got a cleanroom to work in.

In the videos below [The Developer Guy] records the drive while it’s in use, and at one point puts a microscope on top of the plastic to get a close-up view of the read/write head twitching back and forth. We particularly liked the time-lapse of the drive being formatted, as you can see the arm smoothly moving towards the center of the drive. Unfortunately the movement of the platters themselves is very difficult to perceive given their remarkably uniform surface, but make no mistake, they’re spinning at several thousand RPM.

Have an old mechanical drive of your own that you’re not sure what to do with? We’ve seen them turned into POV clocks, impromptu rotary encoders, and even surprisingly powerful blower fans.

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