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Hackaday Links: May 23, 2021

The epicenter of the Chinese electronics scene drew a lot of attention this week as a 70-story skyscraper started wobbling in exactly the way skyscrapers shouldn’t. The 1,000-ft (305-m) SEG Plaza tower in Shenzhen began its unexpected movements on Tuesday morning, causing a bit of a panic as people ran for their lives. With no earthquakes or severe weather events in the area, there’s no clear cause for the shaking, which was clearly visible from the outside of the building in some of the videos shot by brave souls on the sidewalks below. The preliminary investigation declared the building safe and blamed the shaking on a combination of wind, vibration from a subway line under the building, and a rapid change in outside temperature, all of which we’d suspect would have occurred at some point in the 21-year history of the building. Others are speculating that a Kármán vortex Street, an aerodynamic phenomenon that has been known to catastrophically impact structures before, could be to blame; this seems a bit more likely to us. Regardless, since the first ten floors of SEG Plaza are home to one of the larger electronics markets in Shenzhen, we hope this is resolved quickly and that all our friends there remain safe.

In other architectural news, perched atop Building 54 at the Massachusetts Institute of Technology campus in Cambridge for the last 55 years has been a large, fiberglass geodesic sphere, known simply as The Radome. It’s visible from all over campus, and beyond; we used to work in Kendall Square, and the golf-ball-like structure was an important landmark for navigating the complex streets of Cambridge. The Radome was originally used for experiments with weather radar, but fell out of use as the technology it helped invent moved on. That led to plans to remove the iconic structure, which consequently kicked off a “Save the Radome” campaign. The effort is being led by the students and faculty members of the MIT Radio Society, who have put the radome to good use over the years — it currently houses an amateur radio repeater, and the Radio Society uses the dish within it to conduct Earth-Moon-Earth (EME) microwave communications experiments. The students are serious — they applied for and received a $1.6-million grant from Amateur Radio Digital Communications (ARDC) to finance their efforts. The funds will be used to renovate the deteriorating structure.

Well, this looks like fun: Python on a graphing calculator. Texas Instruments has announced that their TI-84 Plus CE Python graphing calculator uses a modified version of CircuitPython. They’ve included seven modules, mostly related to math and time, but also a suite of TI-specific modules that interact with the calculator hardware. The Python version of the calculator doesn’t seem to be for sale in the US yet, although the UK site does have a few “where to buy” entries listed. It’ll be interesting to see the hacks that come from this when these are readily available.

Did you know that PCBWay, the prolific producer of cheap PCBs, also offers 3D-printing services too? We admit that we did not know that, and were therefore doubly surprised to learn that they also offer SLA resin printing. But what’s really surprising is the quality of their clear resin prints, at least the ones shown on this Twitter thread. As one commenter noted, these look more like machined acrylic than resin prints. Digging deeper into PCBWay’s offerings, which not only includes all kinds of 3D printing but CNC machining, sheet metal fabrication, and even injection molding services, it’s becoming harder and harder to justify keeping those capabilities in-house, even for the home gamer. Although with what we’ve learned about supply chain fragility over the last year, we don’t want to give up the ability to make parts locally just yet.

And finally, how well-calibrated are your fingers? If they’re just right, perhaps you can put them to use for quick and dirty RF power measurements. And this is really quick and really dirty, as well as potentially really painful. It comes by way of amateur radio operator VK3YE, who simply uses a resistive dummy load connected to a transmitter and his fingers to monitor the heat generated while keying up the radio. He times how long it takes to not be able to tolerate the pain anymore, plots that against the power used, and comes up with a rough calibration curve that lets him measure the output of an unknown signal. It’s brilliantly janky, but given some of the burns we’ve suffered accidentally while pursuing this hobby, we’d just as soon find another way to measure RF power.

Overclocking And Watercooling The TI-84, Just Cause

The TI-84 is an enduring classic – the calculator that took many through high school, college and beyond. A hacker’s favorite, it’s been pushed to the limits in all sorts of ways. The crew at [Linus Tech Tips] decided to join in the fun, overclocking a TI-84 Plus and adding water cooling to boot. 

The TI-84 uses a simple resistor capacitor circuit to generate its clock, making it overclocking it a cinch. By changing the resistor value in the circuit, the clock can be made to run faster. The team have some issues with pads delaminating from the PCB, but manage to sub in a trimpot which lets the clock be changed on the fly. A boost of 10MHz over stock gets the calculator operating at 26MHz, with notably quicker performance in the TI port of Doom 2. Without accurate measurement of CPU temps, it’s hard to say whether watercooling the calculator is justified. However, the team do a great job of entirely overengineering the solution, with a custom-made cooling block hooked up to a massive spherical reservoir.

With the stability issues inherent in overclocking, and the unwieldy watercooling tubes, it’s not a good hack in the practicality sense. It is, however, quite amusing, and that’s always worth something. TI calculators have long been targets for hackers, and you can even get them online if you so desire. Video after the break.

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Pocket Forth Invades Your TI Calculator

TI certainly have certainly seen off rivals such as HP or Casio to capture the lion’s share of the calculator market. The TI-84 is a real staple, and with as many units as there are out there, hacking them is a given. However, selecting an operating system for the machine can be a hassle. TI-OS is proprietary and doesn’t really want to let you do everything you’d like to. There are alternatives, but many of them won’t let you easily use your calculator to be — well — a calculator.

[Siraben] has zkeme80 which is essentially ANS Forth (mostly) with extensions for the TI hardware. You can easily extend the system, of course, because it is Forth. You can also use the machine for its intended purpose easily.

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That TRS Jack On Your Graphing Calculator Does More Than You Think

It’s not Apple IIs, and it’s not Raspberry Pis. The most important computing platform for teaching kids programming is the Texas Instruments graphing calculator. These things have been around in one form or another for almost three decades, and for a lot of budding hackers out there, this was the first computer they owned and had complete access to.

As hacking graphing calculators is a favorite for Maker Faires, we were pleased to see Cemetech make it out to this year’s World Maker Faire in New York last weekend. They’re the main driving force behind turning these pocket computers with truly terrible displays into usable computing platforms.

As you would expect from any booth, Cemetech brought out the goods demonstrating exactly what a graphing calculator can do. The most impressive, at least from a soldering standpoint, is their LED cube controlled by a graphing calculator. The electronics are simple, and just a few 595s and transistors, but this LED cube is taking serial data directly from the link cable on a graphing calculator. Of course, the PCB for the LED cube is designed as an Arduino shield for ease of prototyping, but make no mistake: this is an LED cube controlled by a calculator.

If you can send serial data to a shift register from a graphing calculator, that means you can send serial data to anything, bringing us to Cemetech’s next great build featured this year. It’s an N-gauge model train, with complete control over the locomotive.

There’s a lot more to controlling model trains these days than simply connecting a big ‘ol variac to the tracks. This setup uses Direct Cab Control (DCC), a system that modulates commands for locomotives while still providing 12-15V to the tracks. There’s a good Arduino library, and when you have that, you can easily port it to a graphing calculator.

Cemetech is one of the perennial favorites at Maker Faire, and over the years we’ve seen everything from the Ultimate TI-83+ sporting an RGB backlight and a PS/2 port to a game of graphing calculator Whac-A-Mole. It’s all a great example of what you can do with the programmable computer every 90s kid had, and an introduction to computer programming education, something Cemetech is really pushing out there with some hard work.

A Calculator With 3G Inside

For many of us, a calculator is something we run as an app on our mobile phones. Even the feature phones of a couple of decades ago bundled some form of calculator, so that particular task has joined the inevitable convergence of functions into the one device.

For [Scott Howie] though, a mobile phone is something to run as an app on his calculator. He’s integrated a cellphone module into his TI-84 calculator, and though perhaps it won’t be knocking Apple or Samsung off their pedestals just yet, it’s fully functional and both makes and receives calls.

To perform this feat he’s taken the cellphone module and one of the tiniest of Arduino boards, and fitted them in the space beneath the TI-84’s keyboard by removing as much extraneous plastic as he could. The calculator’s 4 AAA cells could not supply enough power on their own, so he’s supplemented them with a couple more, and replaced the alkaline cells with rechargeables. A concealed switch allows the cellphone to be turned off to preserve battery life.

The calculator talks to the Arduino via a slightly unsightly external serial cable, and all his software is handily available in a GitHub repository. His video showing the whole build in detail is below the break, so if you fancy a calculator with cellular connectivity, here’s your opportunity. Hang on — couldn’t you use a device like this for exam cheating?

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Animated GIFs On A Graphing Calculator

The TI-84 Plus graphing calculator has a Z80 processor, 128 kilobytes of RAM, and a 96×64 resolution grayscale LCD. You might think a machine so lean would be incapable of playing video. You would be right. Animated GIFs, on the other hand, it can handle and [searx] is here to tell you how.

Before assembling his movie, [searx] first needed to grab some video and convert it to something the TI-84 could display. For this, he shot a video and used Premiere Pro to reduce the resolution to 95 by 63 pixels. These frames were saved as BMPs, converted to monochrome, renamed to pic0 through pic9, and uploaded to the calculator’s RAM.

To display the animated GIF, [searx] wrote a small program to cycle through the images one at a time. This program, like the images themselves, were uploaded to the calculator over the USB connector. Playing these animated GIFs is as simple as calling the program, telling it how fast to display the images, and standing back and watching a short flip-book animation on a calculator.

ArTICam Interfaces Game Boy Camera With TI Calculators

[Christopher Mitchell] has given Texas Instruments calculators the ability to capture images through a Game Boy Camera with ArTICam. First introduced in 1998, The Game Boy Camera was one of the first low-cost digital cameras available to consumers. Since then it has found its way into quite a few projects, including this early Atmel AT90 based hack, and this Morse code transceiver.

TI calculators don’t include a Game Boy cartridge slot, so [Christopher] used an Arduino Uno to interface the two. He built upon the Arduino-TI Calculator Linking (ArTICL) Library  to create ArTICam. Getting the Arduino to talk with the Game Boy Camera’s M64282FP image sensor turned out to be easy, as there already are code examples available. The interface between the camera sensor and the Arduino is simple enough. 6 digital lines for an oddball serial interface, one analog sense line, power and ground. [Christopher] used a shield to solder everything up, but says you can easily get away with wiring directly the Arduino Uno’s I/O pins. The system is compatible with the TI-83 Plus and TI-84 Plus family of calculators. Grabbing an image is as simple as calling  GetCalc(Pic1) from your calculator program.

So, If you have an old calculator lying around, give it a try to enjoy some 128×123-pixel grayscale goodness!