Pocket Calculator Emulates Pocket Calculator

msp430 Calc Emu

[Chris] has built a pocket calculator that emulates… a pocket calculator. Two pocket calculators, in fact. Inspired by [Ken Shirriff's] incredible reverse engineering of the Sinclair scientific calculator, [Chris] decided to bring [Ken's] Sinclair and TI Datamath 2500II simulators to the physical world.

Both of these classic 70′s calculators are based on the TMS0805 processor. The 0805 ran with 320 11-bit words of ROM and only three storage registers. Sinclair’s [Nigel Searle] performed the real hack by implementing scientific calculator operations on a chip designed to be a four function calculator.

[Chris] decided to keep everything in the family by using a Texas Instruments msp430 microcontroller for emulation. He adapted [Ken's] simulator code to run on a MSP430G2452. 256 bytes of RAM and a whopping 8KB of flash made things almost too easy.[Chris'] includes ROMs for both the TI and the Sinclair calculators. The TI Datamath ROM is default, but by holding the 7 key down during boot, the Sinclair ROM is loaded. The silk screen includes key icons for both calculators, as well as some Doge-inspired wisdom on the back.

All joking aside, these really are amazing little calculators. Children of the 60′s and 70′s will be taken back when they see the LEDs flash as the emulated TMS0805 performs algorithmic arithmetic. [Chris'] code is up on Github. While he hasn’t released gerbers yet, he does have images of his PCB layout on the 43oh.com forums.

[Read more...]

A Masterpiece Of 3D Printed Case Modding. With An Ouya.


We’ve seen a few of [Downing]‘s portabalized console builds before, but this one is his first build in over two years. That’s a lot of time, and since then he’s picked up a lot of great fabrication techniques, making this one of the best looking portables we’ve ever seen. It’s a repackaging of an Ouya, but we won’t hold that against him, it’s still an amazing piece of work.

In the build log, [Downing] started off this build by using a 3D printed enclosure, carefully milled, filled, and painted to become one of the best one-off console repackagings we’ve ever seen. The speaker and button cutouts were milled out, and an amazing backlit Ouya logo completes the front.

Stuffing the Ouya controller inside a case with a screen, battery, and the console itself presented a challenge: there is no wired Ouya controller. Everything is over Bluetooth. Luckily, the Bluetooth module inside each controller can be desoldered, and slapped on a small breakout board that’s stuffed in the case.

It’s a great build, and in [Downing]‘s defense, the Ouya is kinda a cool idea. An idea much better suited to a handheld device, anyway. Videos below.

[Read more...]

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.

[Read more...]

2048: Embedded Edition

Embedded touch version of 2048 tile gameHow ’bout that 2048 game? Pretty addictive, huh? Almost as addictive as embedded systems are, at least if you’re [Andrew]. Armed (pun intended) with a Nucleo F4 and a Gameduino 2 shield, he decided to have a go at making an embedded version of the popular tile pusher web game.

If you’re unfamiliar with the Nucleo boards from STMicroelectronics, check out our post on the Nucleo family from a couple of months ago. The Gameduino 2 shield ships with a 4.3″ touchscreen driven by an FT800 GPU EVE. [Andrew] wrote his own driver for it and his blog post goes into great detail about its programming model and the SPI read, write, and command functions he wrote. Full code is available from [Andrew]‘s repo.

He started by generating a blank screen based on clues found in the Gameduino 2 source. Pretty soon he had rendered a rectangle and then a full 2048 board. A minor difference between [Andrew]‘s creation and the original is that his always creates new tiles as ’2′ while the web game cranks out the occasional ’4′.

We were unable to embed [Andrew]‘s gameplay videos, but you’ll find two on his blog.


Throwback Handheld Built with Modern Hobby Hardware


Remember all of those fantastically horrible handheld LCD games that hit the toy stores back in the ’90s. You know, the ones that had custom LCD screens to make for some fake animation. Here’s an example of what those should have been. It’s an LCD-based handheld with some soul.

The entire thing is roughly the size of a television remote, with a 3D printed case making it very presentable. But looking at the wiring which hides inside proves this is one-of-a-kind. The Arduino Pro Mini is probably the biggest difference in technology from back in the day compared to now. It has plenty of space for all of the different settings and games shown off in the clip below. The user interface itself is definitely a throw-back though. The Nokia 3310 screen boasts a whopping 84×48 pixel monochrome area. There are four buttons serving as a d-pad, and two as action buttons. Perhaps the greatest feature (besides the printed case we already mentioned) is the ability to recharge the internal battery via USB.

[Zippy314] built this with his son. What’s more fun: learning to program the games, or mastering them and discovering the bugs you missed along the way?


[Read more...]

Update: Tetris Handheld Get PCB and Case


Check out this sweet-piece of homemade handheld gaming! [Jianan Li] has been hard at work on the project and published the updates in two parts, one that shows off the PCB he had fabbed for the project, and another which details the 3D printed case. This is, of course, is the culmination of the Tetris project we first saw as an incredbily packed, yet thouroughly tidy breadboarded circuit.

We really enjoy the 8-sided PCB design which hosts all the parts and gives you a place to hold and control the unit, all without seeming to waste much real estate. The case itself is quite impressive. The openings for the square-pixel LED matrices (the original design had round pixels) and the bar graphs all have nice bevel features around them. The control area has a pleasant swooping cutout, with blue buttons which stand out nicely against the red. Check out the slider switch by his left thumb. He printed matching covers for this slider, and the two that stick out the bottom. Also on the bottom are female pin headers so that you don’t need to disassemble the case to interface with the electronics.

All of this and more are shown off in the clip after the break.

[Read more...]

Improve Your HT Ham Radio by Adding a Counterpoise Antenna Wire


We found an interesting tip that might just improve the performance of those small affordable handheld ham radios called a “Handy Talky” or HT for short in ham vernacular. [RadioHamGuy] posted an interesting video on adding a counterpoise antenna wire to an HT. He claims it will noticeably improve both transmit and receive by making a quarter-wave monopole into a makeshift dipole antenna system.

Per his instructions you basically add a short wire to the antenna’s outer ground connection or to an equivalent case screw that’s electrically connected to the antenna’s ground side. Apparently this can be referred to as a Tiger Tail and does make it look like your HT has a tail. You would construct a counterpoise antenna wire 11.5 inch for VHF, 6.5 for UHF and about 19.5 inches for an OK performing dual band VHF/UHF radio.

Normally with a handheld radio the counterpoise (ground) is your own body as you are holding the HT. This is because the capacitance of your body makes a good counterpoise under normal conditions. It would be interesting to hear what others find for performance when adding a counterpoise antenna wire.

You can watch [RadioHamGuy’s] full construction tutorial video for multiple radio types after the break.

[Read more...]