Reverse geocache based on STM32 and GPS wristwatch

reverse_geocache

[Renaud Schleck] somehow got lucky enough to find a GPS wristwatch in the trash. It had a broken LCD screen so its wouldn’t be of much use on that next hiking trip, but he knew it still had potential. He used the GPS module and a few other parts to build this reverse geocache box.

Reverse geocache is a container that is locked, opening only in a pre-defined geographic location. We’ve seen plenty of these projects around here, like this one that talks, or this one which was given as a Christmas gift. They’re popular projects both because of the unique method of getting at the prize inside, and because it doesn’t take a whole lot of hardware to build one. Once [Renaud] had the GPS module he simply need a user interface, locking mechanism, and a microcontroller to pull it all together.

The interface uses a screen from an old cellphone and one push button. The latching system is a tiny geared motor salvaged from a Laptop optical drive. These, along with the GPS watch board are all monitored by the STM32 microcontroller which he programmed using OpenOCD and the Bus Pirate.

[via Reddit]

Disassembling and reprogramming Webkeys

Webkeys are small, inexpensive USB devices which launch a web browser when plugged into a computer. They’re given out as a promotional item, but they can be fun to hack as well. [Brad Antoniewicz] recently got his hands on one and decided to crack it open to see what he could accomplish.

The majority of the device was packaging but it didn’t take him long to get down to the guts seen here. There are two units shown in the image above so that we can get a look at both sides of the circuit board. As you can see, there’s a chip-on-board processor (that black blob) that handles the USB connectivity. But the data which is pushed to a computer is stored in that EEPROM chip at the top. It’s got legs which are just begging to be probed. [Brad] wasn’t able to find the exact datasheet but he got some clues as to the pinout. Using his Bus Pirate he was able to establish communications and sniff the i2c traffic. With that success he went on to overwrite that data. You can see a quick demonstration of it after the break.

[Brad] hopes to do a bit more with the hardware. He thinks those four pads can be used to reprogram the MCU. We’ll keep our eyes out for updates as he moves along on that mission.

Continue reading “Disassembling and reprogramming Webkeys”

ARM-based debugging tool aims to improve on the Bus Pirate performance

The Bus Pirate is a fantastic development tool. It does an amazing job at a lot of different things. And as it has matured, community support has driven it to new areas beyond the original design. This is where its hardware holds back performance a little bit. For instance, as an I2C or SPI sniffer it has limited capture speed. That’s the type of thing that this board could improve upon. It’s a debugging tool based on an STM32 F4 microcontroller. That’s an ARM Cortex-M4 chip which runs at 168 MHz, and has 192 KB of SRAM.

[TitanMKD] has been working on the design but it is still just in digital form. Since there’s no prototype there is also no firmware for the device. That’s a tall mountain to climb and it’s one of the reasons we’re featuring the project now. [Titan’s] plan is to model this after the Bus Pirate interface. We think it’s a good idea since a lot of folks have already learned the syntax. We didn’t see a contact form on his site, but if you’re interested in contributing to the project you might want to leave a comment here or on his project page (linked above).

Using your bench tools to test a new display

It usually takes a bit of work to gain confidence when it comes to using new parts. [Glitch] got his hands on this OLED display which is manufactured by Sabernetics and wanted to give it a whirl before building a project around it. He grabbed his Bus Pirate to help learn the ins and outs of the new part.

The 96×16 Dot-Matrix display uses the i2c protocol, keeping the pin count really low (six pins for: ground, reset, clock, data, chip select, and voltage). Since the Bus Pirate gives you command-line-like access to i2c it’s a natural choice for a first test. In fact, the tool has been our go-to device for that protocol for most projects.

The first commands sent are configuration values for the SSD1306 that drives the display. These configure contrast, voltage conversion, and other important values necessary to power on the display. It sprung to life, showing random pixels since the RAM had not yet been initialized. With that success [Glitch] moved on to the Bus Pirate’s scripting capabilities and ended up with a Python script that drives the demo seen above. Now that he knows the commands he needs, it’ll be a lot easier to write code for a microcontroller driver.

Reprogramming promotional USB dongles to launch custom URLs

webkey-hacking

The teachers at [Jjshortcut’s] school were each given a Webkey by the administration as a promotional item of sorts, but most of the staff saw them as useless, so they pitched them. [Jjshortcut] got his hands on a few of them and decided to take one apart to see what made them tick.

He found that the device was pretty simple, consisting of a push button that triggers the device to open the Windows run prompt, enter a URL, and launch Internet Explorer. Since the microcontroller was locked away under a blob of epoxy, he started poking around the onboard EEPROM with his Bus Pirate to see if he could find anything interesting there. It turns out he was able to read the contents of the EEPROM, and since it was not write protected, he could replace the standard URL with that of his own web site.

While it’s safe to say that without a new microcontroller the Webkeys probably can’t be used for anything more exciting than launching a browser, [Jjshortcut] can always reprogram the lot and drop them in random locations to drive some fresh traffic to his web site!

[Thanks, Wouter]

Microcontroller based audio volume level compressor

In an effort listen to his music on shuffle without the need to touch the volume knob [Mike] build his own automatic volume leveling hardware. He knows what you’re thinking right now: there’s software to do that for you. But building the feature in hardware is a great stepping off point for a project.

He started the prototype using LabVIEW along with a Mobile Studio development board and a Bus Pirate. This project will be a mix of digital and analog components and it’s a bit easier starting off the exploration with these tools rather than jumping right into the AVR code.

The circuit will sample the incoming audio, modify it accordingly, and output the result. The output side is where the Bus Pirate really shines. He’s using some MCP42010 digital potentiometer chips to make the necessary changes to the levels. They communicate via SPI and it’s nice to have the Bus Pirate’s terminal to issue commands without the need to reflash a microcontroller.

[Mike] made a video showing an audio waveform with and without the hardware leveling. Sound quality is still great, and each clip is played at a reasonably comfortable listening level. We’ve embedded that demonstration after the break.

Continue reading “Microcontroller based audio volume level compressor”

Using an ATmega8 to program PIC24FJ chips

[Fezoj] likes to play around with microcontrollers and decided that he wanted to try a Bus Pirate as a new tool in his adventures. Since it’s open hardware he had his own board made and populated it himself. The trouble is, he works only with AVR chips and doesn’t have a PIC programmer. No problem, he figured out how to flash the PIC24FJ using an ATmega8.

To get started, he grabbed a copy of the flash programming specifications from Microchip. Once he had implemented the protocol in the AVR code, it was just a matter of getting the downloaded PIC firmware to the AVR. An RS232 chip gives him the serial connection he needs, with the help of his own programming software written with Visual Studio.

It’s not a robust solution for prototyping on the PIC platform, but maybe it could be developed for that purpose. For now, all he needed was a bootloader so that he could flash the Bus Pirate via a USB connection.

[via Dangerous Prototypes]