Send Wireless TXT between Two TI Calculators

 

TI calculators with wireless circuitry

One day while sitting in class in a Cornell University schoolroom, [Will] and [Michael] thought how cool it would be to send text messages to each other via their Texas Instruments calculators.  Connecting the two serial ports with a serial cable was out of the question. So they decided to develop a wireless link that would work for both TI-83 and TI-84 calculators.

The system is powered by a pair of ATmega644’s and two Radiotronix RF Modules that creates a wireless link between the two serial ports. The serial ports are 3 wire ports, which can be used for several things, including acting as a TV out port. [Will] and [Michael] reverse engineered the port’s protocol and did an excellent job at explaining it in full detail. Because they are dealing with the lowest level of the physical protocol, there is no need for them to deal with higher levels like checksums, header packets, ext.

Be sure to stick around after the break to see a video of the project in action. It’s quite slow for today’s standards. If you have any ideas on how to speed it up, be sure to let everyone know in the comments.

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GPS For A Graphing Calculator

GPS [Chris], graphing calculator hacker extrordinaire, has seen a few of his projects show up on the front page of Hackaday, mostly involving builds that turn graphing calculators like the TI-84 Plus shown above into something that copies a few features from a smartphone. His latest build, a hardware GPS module attached to the TI-84 Plus, is yet another feather in his cap of awesome and impractical addition to a classic piece of hardware.

There were two major technical challenges behind adding GPS to a graphing calculator. The first of these was powering a GPS sensor. Many a calculator modder has put a lot of work into documenting the USB port on the 84 Plus, revealing it is a USB OTG port, capable of serving as a host or device. It also supplies 5V of power to just about anything, burning through batteries as a result.

The next challenge was reading the data coming off the GPS sensor at 4800bps.The TI-84 Plus series of calculators have a series of interrupts that can fire at fractions of the 15MHz clock. By setting the timer up to fire every 197 clock ticks and dividing again by 16, [Chris] can read data at 4758.9bps. It’s close enough to get most of the data, and the checksum included in the NMEA protocol allows the software to discard bad messages.

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Web-based TI graphing calculator emulator

jstified_ti-graphing-calculator-emulator

You can leave the TI graphing calculator at home thanks to this web-based TI-83 and TI-84 emulator. As with pretty much all emulators, this depends on a ROM image from the actual hardware to work. But if you have one of the supported calculators (TI-83+, TI-83+ SE, TI-84+, or TI-84+SE) you can dump the image yourself and this should work like a charm.

[Christopher Mitchell] calls the project jsTIfied because he wrote it in JavaScript and HTML5 (that’s where the js comes from) and it’s based on the Texas Instruments line of hardware (hence the capital TI). After agreeing that you’re not getting any ROMs from his site you can choose the file to load on your browser. The image of the calculator has working buttons and will show the boot screen just like the real thing. You can use it like normal but you can load load up programs for the environment. See this demonstrated after the break.

We’ve seen some arguments online about the price of the TI line over the years. Prices haven’t dropped much over the decades even though they’re making pretty much the same hardware. It’s cool to see someone figure out how to emulate the hardware — and on a web interface to boot! But we’re left wondering why TI isn’t selling an equivalent app for iOS and Android or at least leveraging what must be millions in each production run for a lower retail price?

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Linux on a Nspire CAS CX Calculator

It’s great to see Linux running on a device in a way that was never intended. [tangrs] has successfully run a Linux kernel on the ARM based Nspire CAS CX graphing calculator. He’s developed an in-place bootloader that allows a kernel to be loaded from within the stock Nspire OS. It also allows for peeking and poking at memory for debugging.

[tangrs] also managed to get USB host mode working on the calculator. This allows for a USB keyboard and Wifi dongle to be connected. At this point, the calculator can connect to the internet and browse using a text-based browser: Links. The calculator runs a SSH server for remote access, and graphical browsing is in the works.

It looks like this calculator is on the way to being a handheld Linux device. All of the source for the kernel and bootloader are available on [tangrs]‘s Github and updates on his blog. After the break, check out a video of text-based browsing using a full keyboard.

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Giving graphing calculators a new life

[Christopher] at Cemetech, ever frequent HaD feature for his hacked up graphing calculators, made it to the NYC Maker Faire.

He already posted on his blog he was making the trip up to Maker Faire, but we were lucky enough to catch up with him. Two things: the name of his blog isn’t ‘cement tech’, but ‘chem tech.’ Apparently he hates it when it’s mispronounced.

Secondly, he’s been turning in the TI-83s for a Casio Prizm graphing calculator. In the video above he tells us he’s gotten a few homebrew games running on the Prizm, a Lua interpreter, and is currently working on digging around the operating system.

Toorcamp: Quadcopter Controlled By a TI-84+

What happens when you combine a TI-84+ graphing calculator with an added bluetooth module, a 1 Watt Alfa wifi dongle, and a Parrot Wifi Quadcopter? You get a long range quadcopter that’s controlled from the TI-84+ directional pad.

This TI-84+ looks like a standard issue school calculator, but [Owen] added an ATTiny13 microcontroller and a bluetooth module which sniffs the I/O port of the calculator. This allows for bi-directional communication with a laptop. He wrote a few Python scripts on the laptop to receive data from the calculator and send commands to the Parrot Quadcopter. The high-powered wifi module allowed for pretty good range with the Quadcopter, which was flown across the Toorcamp grounds.

Of course, having an innocent looking calculator with wireless communications has some other uses. Data could be displayed on the calculator from a phone over bluetooth. How about accessing Wikipedia or WolframAlpha from your calculator? Despite the possibilities, [Owen] did say that he’s never used it to cheat on tests.

Global CALCnet: your TI-83 just acquired Internet

Global CALCnet lets you connect your TI graphic calculator to the Internet and use your favorite services like instant messaging and Internet relay chat. It also provides the option of worldwide multiplayer functionality for games ported to the device such as Scorched Earth and Tetris. We looked in on [Christopher Mitchell's] CALCnet in December when it was being used to create local area networks with the adding machines. He’s taken that up a notch with a helping hand from Arduino. An Arduino board is used to connect the serial communications from the calculator to an Internet connected PC via the Arduino’s USB capabilities.

Think this will waste a lot of time in schools? Unlikely since an Internet connected computer is integral for this system to work. If you have a computer in front of you why waste time on the calculator network? Still, how hard would it be to build a WiFi module that can directly connect them to an access point? That may be a moot point as the Slashdot article that pointed us to global CALCnet also links to a calculator port of DOOM. It runs quite well, as you can see in the video after the break. This is a must-have for anyone owning a TI Nspire that can run it.

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