The Newest Graphing Calculator Game

Certainly everyone remembers passing time in a boring high school class playing games on a graphing calculator. Whether it was a Mario-esque game, Tetris, or BlockDude, there are plenty of games out there for pretty much all of the graphing calculators that exist. [Christopher], [Tim], and their colleagues from Cemetech took their calculator game a little bit farther than we did, and built something that’ll almost surely disrupt whatever class you’re attempting to pay attention in: They built a graphing calculator whac-a-mole game.

This game isn’t the standard whac-a-mole game, though, and it isn’t played on the calculator’s screen. Instead of phyiscal “moles” the game uses LEDs and light sensors enclosed in a box to emulate the function of the moles. In order to whack a mole, the player only needs to interrupt the light beam which can be done with any physical object. The team made extensive use of the ArTICL library which allows graphing calculators to interface with microcontrollers like the MSP432 that they used, and drove the whole thing with a classic TI-84.

This project is a fun way to show what can be done with a graphing calculator and embedded electronics, and it was a big hit at this past year’s World Maker Faire. Calculators are versatile in other ways as well. We’ve seen them built with open hardware and free software, And we’ve even seen them get their own Wi-Fi.

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Hackaday Links: January 10, 2016

Everybody loves cheap stuff, and we hate telling everyone about coupon codes. That said, TI has a new LaunchPad development board they’re promoting. It’s based on the MSP432, the ARM extension of their MSP430 line. The MSP432 is an ARM Cortex M4F, low power, and planned for production later this year.

Here’s your daily CES garbage post. Through a collaboration between Sony and Nissan, a car has become a video game controller controller. A controller plugs into the ODB II port, reads throttle, brake, and steering wheel positions (and buttons on the dash/steering wheel, I guess), and translates that into controller input for a PlayStation 4. What games do they play with a car? You would think Gran Turismo, Rocket League, or other games with cars in them. Nope. Football.

Dangerous Prototypes is a legal Chinese company! [Ian] didn’t say anything about the process about becoming a legal Chinese company because he wrote a blog post, not a book. Shenzhen Dangerous Prototypes Electronics Technology Limited allows them to have an office in the Shenzhen electronics market, hire local and foreign hackers, host Hacker Camp Shenzhen, and allow people to apply for ‘Authorized Authority’ visa letters for the people who need them. Great news for a great company.

The Forge hackerspace in Greensboro, NC is growing. In just over a year they have 160 members and they’ve already outgrown their 3,400 square foot space. Now they’re moving to a larger space that’s twice the size and they’re looking for donations.

People have been taking old iPad screens and turning them into HDMI displays for years now. [Dave] got his mitts on a panel from a Macbook Pro 17″, and turned it into a monitor. It required a $50 LVDS adapter, but the end result is great – a 1920×1200 panel that looks pretty good.

Energia Multitasking uses RTOS on MSP432

We keep wondering where the Arduino world is headed with the hardware getting more and more powerful. If the IDE doesn’t keep up what’s the point? Now we have at least one answer to that problem. Energia is the Arduino-like-framework for Texas Instruments based boards. They just came out with a multitasking system built into Energia targeted at the ARM Cortex-M4F based MSP432 Launchpad which we covered a few weeks back.

The announcement post gives a couple of examples of uses for multitasking. The simplest is blinking LEDs at different rates. If you wanted to do this closer to the metal you’re talking about multiple timers, or multiple compares on a single timer, perhaps a interrupt-driven-system-tick that has a high enough resolution for a wide range of your blinking needs. But these are not always easy to set up unless you are intimately comfortable with this particular architecture. The Energia multitasking will handle this for you. It’s upon the TI Real Time Operating System (TI-RTOS) but wraped in the familiar IDE.

The UI divorces you from thinking about the hardware at all. You simply launch a new tab and start coding as if you’re using a completely separate piece of hardware. The announcement post linked above mentions that these Sketches are running “in parallel”. Well… we know it’s not a multi-core system like the Propeller but we’ll let it slide. It is certainly easier than building your own scheduler for this type of hardware.

[Thanks MycoWx]

Sonar Built from Piezo and Microphone

[Jason] has continued to plug along with his sonar build and recently showed up a monostatic active sonar using a piezo element and microphone. Regular readers will remember [Jason’s] experiments from a Fail of the Week post which focused on his water-proofing woes from a much earlier prototype.

We find this offering far more engaging. He has ditched the ultrasonic module seen in those experiments. The new rig drives the piezo element using a 27V source. After each ping is sent out, the microphone input is immediately captured to detect the return of the audible sound. [Jason] mentions that the TI Launchpad he’s using for the project is fast enough for these experiments but he may switch to a Teensy 3.1 in order to double the RAM and thereby increase the sample size he is able to record.

Of course this is intended for underwater ROVs so his next iteration will involve a DIY hydrophone. We can’t wait to see that one as the process of converting this test rig into one that works underwater evades us. If you have some tips on that topic please let us know in the comments.

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MicroDMA and LEDs

[Jordan] has been playing around with WS2812b RGB LED strips with TI’s Tiva and Stellaris Launchpads. He’s been using the SPI lines to drive data to the LED strip, but this method means the processor is spending a lot of time grabbing data from a memory location and shuffling it out the SPI output register. It’s a great opportunity to learn about the μDMA available on these chips, and to write a library that uses DMA to control larger numbers of LEDs than a SPI peripheral could handle with a naive bit of code.

DMA is a powerful tool – instead of wasting processor cycles on moving bits back and forth between memory and a peripheral, the DMA controller does the same thing all by its lonesome, freeing up the CPU to do real work. TI’s Tiva C series and Stellaris LaunchPads have a μDMA controller with 32 channels, each of which has four unique hardware peripherals it can interact with or used for DMA transfer.

[Jordan] wrote a simple library that can be used to control a chain of WS2812b LEDs using the SPI peripheral. It’s much faster than transferring bits to the SPI peripheral with the CPU, and updating the frames for the LED strip are easier; new frames of a LED animation can be called from the main loop, or the DMA can just start again, without wasting precious CPU cycles updating some LEDs.

Turkey Sous Vide

It’s time once again for Americans to gorge themselves on hormone-laced meats covered in several sauces and gravies, all of which inexplicably contain corn syrup. It’s also Thanksgiving this Thursday, so there’s that, too. If you have a turkey defrosting somewhere, you’ve probably gone over all your cooking options – the oven, a giant propane-heated pot of peanut oil, and yes, even sous vide. [Trey] over at TI came up with a great sous vide controller using a few LaunchPad Booster packs, and surprisingly, he can even cook a turkey.

The basic idea of sous vide is to vacuum pack your protein, put it in a closely-controlled water bath, and cook it so the inside is always the same temperature as the outside. It’s delicious, and it takes a long time. We can automate that, though.

[Trey] is using a USB LaunchPad and a thermocouple BoosterPack to monitor the temperature of a water bath. A custom SSR board is wired right into the heater, and a CC3100 provides a network connection to monitor the bird. While the network may seem a bit superfluous, it’s actually a great idea; sous vide takes hours, and you really don’t dote on your warm tub of water. Being able to receive SMS alerts from a sous vide controller is actually a great idea.

With everything wired up, [Trey] tried out his recipe for deep-fried turkey porchetta. From the pictures, it looks great and according to [Trey] it was the juiciest turkey he’s ever had.

43oh.com Wasn’t Next To The Texas Instruments Booth

In addition to all the cool boards and booster packs found at Texas Instruments’ booth at Maker Faire, the folks from 43oh.com made a showing, but not next to the TI booth. In fairness, the TI booth was right across from NASA. 43oh is cool, but not NASA cool.

[Eric], known on the 43oh forums as [spirilis] showed off a few of the neat bits and bobs developed on the forums including a lightning detector, a VFD clock, a robot, and a whole lot of blinky things. There was an astonishing array of projects and boards at the booth, covering everything from OLEDs to motor drivers.

43oh is an interesting community centered around TI’s microcontrollers, like the AVRfreaks forum built around Atmel’s offerings. 43oh has a very active forum, IRC, and a store featuring projects made by members. It was great to see these guys at the faire, and we wish more of the homespun unofficial communities would make more of a showing at cons in the future.

Sorry about the mic cutting out in the video above. There was a sea of spewing RF near the booth. If anyone has advice for a *digital* wireless mic setup, we’re all ears. This is the current rig.