Building A PDA From Scratch

September 2, 2012 by Brian Benchoff 34 Comments

Extremely powerful ARM microcontrollers have been around for ages now, but only recently have they been available for just a few dollars with a good enough toolchain for some serious development work. [Jose] wanted to develop something awesome with an ARM chip he had lying around, so he built a PDA (Spanish, translation) that can be used as a game console, an oscilloscope, a clock, or a wristwatch. Basically, it’s a portable homebrew computer that can do just about anything.

The hardware is built around an ARM Cortex M4 chip clocked at 170MHz. Included on the PCB is an SD card slot, a JTAG interface, a USB port (only used for charging the battery at this point), and a touch screen LCD controller.

After designing the PCB and enclosure, [Jose] looked around the Internet for a decent GUI library without much success. He eventually found Gwen, a lightweight library for programming GUIs that is easily ported to [Jose]’s hardware.

So far, [Jose] has a few GUI demos up and running on his homebrew PDA, but nothing very useful yet. Still, the fact that [Jose] can get a full-featured ARM tablet-like piece of hardware off the ground without a team of developers brings a smile to our face. We can’t wait to see the state of homebrew ARM devices in a few years when everyone has the requisite hardware and software knowledge.

Reverse Engineering Old PDA Software

March 13, 2012 by Mike Szczys 13 Comments

[Troy Wright] acquired a lot of twenty broken Dell Axim PDAs. This type hardware was quite popular a decade ago, but looks archaic when compared to a modern cell phone. That’s why he was able to get them for a song. After a bit of work he managed to resurrect eight of the units, but was dismayed to find there’s no published method for controlling the back light from software. For some reason this is a deal-breaker for his project. But he knew it was possible because there are some apps for the device which are able to set the back light level. So he found out how to do it by reverse engineering the software.

The trick is to get a hold of the code. Since it’s not open source [Troy] used IDA, a graphical disassember and debug suite. He had some idea of what he was hunting for as the Windows CE developer documentation does mention a way to directly control the graphical hardware independently from the display driver. A few hours of pawing through assembly language, setting break points, and testing eventually led him to the solution.

Smartphone Anti-virus Software

August 1, 2009 by Zach Banks 37 Comments

cracked

With DEFCON and Black Hat going on, a lot of security issues are being made public. This year, cellphones have been a larger target than before. More and more people are carrying complex smartphones that have more ways to go wrong. Even worse, since phones are tied to a billed account, it is possible for malicious software to charge phones discreetly. However, Flexilis promises to keep your phone safe. It’s a free mobile anti-virus that works on most smartphones and PDAs with more clients in the works. It also provides easy backup and recovery options, as well as the ability to wipe the phone if it’s lost. The phone makers really need to fix the probelms, but in the meantime Flexilis can provide a quick response.

[via WSJ Digits]

Apple Newton Dev Kit?

August 3, 2008 by Eliot 3 Comments

[phooky] picked up this bizarre bit of dev hardware three years ago and isn’t really sure what it is. It has lots of general purpose switches, LEDs, and audio jacks. The processor is a StrongARM chip in a ZIF socket. It has two serial ports, a CF, and PCMCIA slot too. Commenter [Glen Raphael] says it looks a lot like the early prototype development boards for the Apple Newton which also used a StrongARM chip. It’s definitely an interesting piece of history. Make sure you check out the full item on NYC Resistor.