TV out for TI calculators using the link port

Do people enjoy wasting 300$ on a bulky convoluted system, that only works for special “Teacher Edition” calculators, and is several years out of date; E.G. the TI-Presenter? [Benryves] certainly does not. So instead of purchasing a TI-Presenter, he made his own TV out system for the TI brand of calculators by using an ATmega168, a few passive components, and some clever code. The only draw backs being: you save 280$, it fits in your pocket, and it works for almost any TI calculator. Bias aside, the system does actually have a few caveats compared to the commercial edition, but the pros far outweigh the cons.

Indestructible TI-89

Sometimes, expensive calculators hit the floor. It’s happened to almost anyone with a graphing calculator from TI or HP. Sadly, they don’t always bounce. After this happened to [Howard C.], an Industrial Engineering student from U. of Iowa, he decided to spend $50 on milling his own replacement case out of aluminum rather than trashing the device over a broken battery compartment. [Howard] chose to send us the story rather than write his own blog, so we’ve included all the great pictures he sent us after the break.

[Read more...]

Open graphing calculator: Beagleboard + R

It looks like we missed the boat on this one but just in case you missed it everywhere else on the Internet, last Saturday [Matt Stack] introduced the world to a completely open source calculator. This marries two heartily tested open source projects; the R Project for Statistical Computing and the Beagleboard. The hardware side of things is very similar to that Linux tablet from back in June. It uses a stock Beagleboard with the BeagleTouch module.

Why do we care? First off, don’t forget what’s under the hood. That ARM processor kicks the 6 MHz Z80 processor found in TI’s calculators to the curb. The R language is a boon as well, offering plots of almost limitless quality and allowing extensibility that can’t be equaled with the current non-open offerings. But mostly because it’s a hack. We like seeing software run on hardware it wasn’t intended for.

Graphic calculator as a spectrum analyzer

[Michael Vincent] turned his TI-84 Plus into a spectrum analyzer. By running some assembly code on the device the link port can be used as an I2C bus (something we’ll have to keep in mind). After being inspired by the cell phone spectrum analyzer he set out to build a module compatible with the calculator by using an I2C port expander to interface with a radio receiver module. Now he can sniff out signals between 2.400 and 2.495 GHz and display the finds like in the image above.

[Thanks Cecil]

Tool Tip: microcontroller timer calculator

uC_timer_calculator

In life and embedded systems timing is everything. Give [Frank's] web-based timer calculator a try. Set your system clock resolution (in hertz making sure you account for any system clock divider), select your timer resolution and prescaler, then calculate based on desired ticks, overflows, or real time. He’s built this with the AVR chips in mind but it should be handy for any family of microcontrollers.

Of course none of this is rocket science, but if you’re trying to use one timer for two differently synchronized events this can save you a lot of trial and error time.

TI lashes out at their biggest fans

ti

Texas Instruments has issued a DMCA notice to United TI, a group of enthusiasts. They had been cracking the keys that sign the operating system binaries in an attempt to gain access and possibly expand on the features. This seems, at least a little counter productive to us. Texas Instruments doesn’t sell the operating system separately do they? These people were buying their product and expanding on it. There is no difference in their income, except possibly a gain as people flock to the one they can modify. Maybe they are charging more for an expanded feature set that is crippled in the OS.

[via slashdot]

8-bit binary calculator

binary_calculator

Don’t feel like shelling out $5 for a fancy factory made calculator that won’t even do binary math? [Jeff] decided to prove his mastery of gates and his disdain for base 10 by building a binary calculator using XOR, AND, and OR chips. Calculations can be input in two ways: through digital logic headers or by three banks of DIP switches used to enter the operator and the two operands. Although limited to addition and subtraction, this is a great way to make sure you really understand digital logic. Take a look at the rough design schematics in his album. The design is modular so if you have one of each gate and a few LEDs sitting around you can give this a whirl.