Over-the-Top Cyberdeck Is Really A Geiger-Deck

November 24, 2020 by Dan Maloney 26 Comments

If you like it when a hack has a little backstory, then you’re going to love this cyberdeck build log, the first half of which reads like a [Tom Clancy] novel. And the build itself looks the part, like something that fell off a military helicopter as the Special Forces operators were fast-roping into a hot LZ. Or something like that.

The yarn that [Paul Hoets] spins around his cyberdeck, dubbed RATIS for Remote Assault and Tactical Intelligence System, is pretty good reading and pretty imaginative. The cyberdeck itself looks very much the part, built into a Pelican-style air travel case as such things usually are. Based on a Raspberry Pi 4, the lid of the case serves as a housing for keyboard and controls, while the body houses the computer, an LCD display, and an unusual peripheral: a Geiger counter, which is very much in keeping with the device’s “mission profile”. The handheld pancake probe and stout coiled cord with its MILSPEC connectors really sell the look, too.

Imaginative backstory aside, the construction method here is what really shines. Lacking access to a 3D-printer to produce the necessary greebling, [Paul] instead used a laser cutter to make acrylic panels with cutouts. The contrast between the black panels and the yellow backgrounds makes it all look official, and it’s a technique to keep in mind for builds of a more serious nature, too.

Feel free to look through our fine collection of cyberdeck builds. Some have a fanciful backstory like [Paul]’s, others are intended for more practical purposes. Build whatever you want, just make sure to tip us off when you’re done.

Eulogy To Arecibo: With Demise Of A Unique Scientific Facility, Who Will Carry The Torch?

November 24, 2020 by Maya Posch 50 Comments

Few telescopes will get an emotional response from the general public when it is ultimately announced that they will be decommissioned. In the case of the Arecibo Observatory in Arecibo, Puerto Rico, the past months has seen not only astronomers but also countless people across the world wait with bated breath after initial reports of damage to the radio telescope’s gigantic dish.

When the National Science Foundation announced that they would be decommissioning the telescope, there was an understandable outpouring of grief and shock. Not only is Arecibo a landmark in Puerto Rico, it is the telescope from iconic movies such as GoldenEye (1995) and Contact (1997). Its data fed public programs such as the Seti@Home and Einstein@Home projects.

Was Arecibo’s demise truly unavoidable, and what does this mean for the scientific community?

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Bet You Didn’t Know Arduinos Are Psychic

November 24, 2020 by Kristina Panos 3 Comments

Are you running out of ways to entertain yourself and your family? If you’ve read all the books and watched all the movies, it might be time to explore the psychic abilities of silicon. [Hari Wiguna] has just the trick to keep them guessing for a good long time.

This trick doesn’t take much, just a couple of Arduinos, some momentary buttons, a number pad, and a large helping of math. As you can see in the demo after the break, there is nothing connecting the two, not even 802.11(n). On the randomizer Arduino, [Hari] generates random numbers with the push of a button until the audience sees one they like. Then [Hari] locks in the number with the other button.

What happens next is key: the randomizer generates another random number, but uses it as a hint to set a sentinel digit. The randomizer Arduino subtracts the larger of the two digits in the number from nine and stores the result as the flag. When the next number comes up that has the flag digit in the correct place, the number after that will be the random number chosen at the beginning.

The psychic Arduino’s secret is that it knows the first guess it receives is special. It does the same sentinel digit math as the randomizer, so when the guesser enters the guess with the sentinel digit, it knows the next number entered is the winner. Clear as mud? Check out the second video below where [Hari] explains the trick, a new take on a magic classic.

Looking for a more exciting way to generate random numbers? Try using fish tanks, lava lamps, or muons from outer space.

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Trashed Tablet Lives Again Thanks To New Charger IC

November 24, 2020 by Tom Nardi 12 Comments

Have you ever pulled a piece of electronics from the trash that looked like nothing was wrong with it, only to take it home and find out it really is dead? Since you’re reading Hackaday, we already know the answer. Trash picking is an honored hacker tradition, and we all know it’s a gamble every time you pull something from the curb. But when the Samsung Galaxy Tab S that [Everett] pulled from the e-waste bin wouldn’t take a charge, he decided to crack it open and see if it was really beyond repair.

The first step was using a USB power meter to see if the tablet was actually pulling any current when plugged in. With just 10 mA on the line, [Everett] knew the device wasn’t even attempting to charge itself. So his next step was to pull the battery and charge it from a bench supply. This got the tablet to wake up, and as far as he could tell, everything else worked as expected. It seemed like the only issue was a blown charging circuit.

Where we’re going, we don’t need ribbon cables.

Now at this point, [Everett] could have just gone online and bought a new motherboard for the tablet and called it a day. But where’s the fun in that? Instead, he wired up a simple charging circuit using a TP4056 IC on a scrap of flexible PCB and mounted it to a square of Kapton tape. He then used 34 AWG magnet wire to connect it between the tablet’s USB port and the battery, bypassing the tablet’s electronics entirely.

The fix worked, but there was a slight problem. Since the TP4056 only goes up to 4.2 V and the battery maxes out at 4.35 V, [Everett] says his hacked charger can only bring the tablet up to 92% capacity according to Android. But considering the alternative, we think its more than a worthy trade-off.

It’s easy to dismiss tablets as largely disposable devices, but this isn’t the first time we’ve seen somebody save one with little more than solder and patience. Of course, what you do with that old tablet once you get it fired back up is another story entirely.

A CPU-Less Computer With A Single NOR-Gate ALU

November 23, 2020 by Dan Maloney 13 Comments

We see a lot of discrete-logic computer builds these days, and we love them all. But after a while, they kind of all blend in with each other. So what’s the discrete logic aficionado to do if they want to stand out from the pack? Perhaps this CPU-less computer with a single NOR-gate instead of an arithmetic-logic unit is enough of a hacker flex? We certainly think so.

We must admit that when we first saw [Dennis Kuschel]’s “MyNor” we thought all the logic would be emulated by discrete NOR gates, which of course can be wired up in various combinations to produce every other logic gate. And while that would be really cool, [Dennis] chose another path. Sitting in the middle of the very nicely designed PCB is a small outcropping, a pair of discrete transistors and a single resistor. These form the NOR gate that is used, along with MyNor’s microcode, to perform all the operations normally done by the ALU.

While making the MyNor very slow, this has the advantage of not needing 74-series chips that are no longer manufactured, like the 74LS181 ALU. It may be slow, but as seen in the video below, with the help of a couple of add-on cards of similar architecture, it still manages to play Minesweeper and Tetris and acts as a decent calculator.

We really like the look of this build, and we congratulate [Dennis] on pulling it off. He has open-sourced everything, so feel free to build your own. Or, check out some of the other CPU-less computers we’ve featured: there’s the Gigatron, the Dis-Integrated 6502, or the jumper-wire jungle of this 8-bit CPU-less machine.

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The Mystery Of A Particular ATtiny85 Fuse

November 23, 2020 by Inderpreet Singh 17 Comments

First-timers playing with 8-bit micros such as the AVR and PIC will at some point in their lives, find themselves locked out of their MCUs. This is usually attributed to badly configured fuses that disable certain IO functions rending the device unprogrammable via conventional ICSP methods. [Uri Shaked] shares his story of how his ATtiny85 got locked and became the subject of a lengthy investigation into fuse bit configurations.

[Uri]’s journey started when he accidentally left some pins of the device connected to a second board while he was flashing the firmware. He quickly researched online for a solution for the problem and it turns out, there are a number of recipes to resolve the issue. As it turns out, his problem was not so straight-forward and warranted more digging. [Uri] ended setting up a High Voltage Programming serial programming setup and then probing the communications. He discovered that the chip refused to reset its fuses and would reject attempts to set fuses.

Further investigation of the fuse bits and reading them proved useful in understanding that the memory protection features were preventing alteration of the device. The quick-fix was to erase the ATtiny and things were back to normal thereafter. [Uri] details his pursuit of reading and comparing fuse bits from the impacted chip against a fresh device which is where he makes the discovery. The write-up is a case study in the investigation into the idiosyncrasies of device programming and will be a great resource for many and reduce hair loss for some.

Once you get your hands on an ATTINY, there are a number of small experiments to be done to cure boredom. Be sure to share your experiments and stories with us to inspire the masses.