Sometimes GPS watches are too good to be left with their stock firmware. [Renaud] opened his Kalenji 300 GPS watch, reverse engineered it in order to upload his own custom firmware.
The first step was to sniff the serial traffic between the PC and the microcontroller when upgrading firmware to understand the protocol and commands used. [Renaud] then opened the watch, figured out what the different test points and components were. He used his buspirate with OpenOCD to extract the existing STM32F103 firmware. The firmware helped him find the proper value to store in a dedicated register for the boot loader to start.
By looking at the disassembly code he also found the SPI LCD initialization sequence and discovered that it uses a controller similar to the ST7571. He finally compiled his own program which uses the u8glib graphics library. Follow us after the break for the demonstration video.
Continue reading “Reverse Engineering a GPS Watch to Upload Custom Firmware”
[Herp] just shared a nice 1MHz Arbitrary Waveform Generator (right click -> translate to English as google translation links don’t work) with a well designed user interface. His platform is based around a PIC32, a TFT module with its touchscreen and the 75MHz AD9834 Direct Digital Synthesizer (DDS). Of course the latter could generate signals with frequencies up to 37.5MHz… but that’s only if two output points are good enough for you.
As you can see in the video embedded below, the ‘tiny dds’ can generate many different kinds of periodic signals and even ones that are directly drawn on the touchscreen. The offset and signal amplitude can be adjusted using several operational amplifiers after the DDS ouput and a separate SMA TTL output is available to use a PIC32 PWM signal. The platform can read WAV audio files stored on microSD cards and also has an analog input for signal monitoring. Follow us after the break for the video.
Continue reading “An Open Source 1MHz Arbitrary Waveform Generator with an Awesome UI”
[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.
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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.
Continue reading “A Masterpiece Of 3D Printed Case Modding. With An Ouya.”
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.
Continue reading “Send Wireless TXT between Two TI Calculators”
How ’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.
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?
Continue reading “Throwback Handheld Built with Modern Hobby Hardware”