Let’s say you’re working on a project, and you need a microcontroller. Which chip do you reach for? Probably the one you’re most familiar with, or at least the one whose programmer is hiding away in a corner of your desk. Choosing a microcontroller is a matter of convenience, but it doesn’t have to be this way. There are dozens of different ARM cores alone, hundreds of 8051 clones, and weirder stuff including the Cypress PSoC and TI’s MSP430. Which one is best? Which microcontroller that costs under a dollar is best? That’s the question [Jay Carlson] tried to answer, …read more http://pje.fyi/PzjC2n
The invention of the transistor ushered in a lot of technologies that we now take for granted, and one of the less-thought-about areas that it improved living conditions worldwide was by making the touch-tone phone possible. No longer would the world have to fuss with dials to make phone calls, they could simply push some buttons. This technology is still in use today, and it is possible to build external phone dialers that use these tones to make phone calls, as [SunFounder] demonstrates with his latest project.
The tones that a phone makes when a button is pressed correlate with …read more http://pje.fyi/PYmGhw
By now it might seem like there’s no new way to build a binary clock. It’s one of the first projects many build to try out their first soldering irons, so it’s a well-traveled path. Every now and then, however, there’s a binary clock that takes a different approach, much like [Stephen]’s latest project which he calls the byte clock.
The clock works by dividing the 24-hour day into half and using an LED to represent this division, which coincidentally works out to representing AM or PM. The day is divided in half over and over again, with each division …read more http://pje.fyi/PMd898
A big problem with restoring old arcade or pinball machines is finding original parts to get them running again. That’s part of the fun, though; when something finally works after weeks or months of effort. On the other hand, sometimes the only hope for old parts that will never be in a pinball machine again is for [Randy] to come across them. One of those parts he had lying around was a backglass for an old machine, and decided to turn it into a unique word clock.
The original pinball machine was built in 1956, and despite its age the …read more http://pje.fyi/PJbqhF
Writing code for embedded applications can be difficult. There are all sorts of problems you can run into – race conditions, conflicting peripherals, unexpected program flow – any of these can cause havoc with your project. One thing that can really mess things up is if your microcontroller is getting stuck on a routine – without the right debugging hardware and software, this can be a tricky one to spot. [Terry] developed a microcontroller load meter just for this purpose.
It’s a simple setup – a routine named loadmeter-task on the microcontroller sends a train of pulses to a mechanical …read more http://pje.fyi/P8YlZ9
C++ has been quickly modernizing itself over the last few years. Starting with the introduction of C++11, the language has made a huge step forward and things have changed under the hood. To the average Arduino user, some of this is irrelevant, maybe most of it, but the language still gives us some nice features that we can take advantage of as we program our microcontrollers.
Modern C++ allows us to write cleaner, more concise code, and make the code we write more reusable. The following are some techniques using new features of C++ that don’t add memory overhead, reduce …read more http://pje.fyi/P4yCBx
[Sami Pietikäinen] was working on an embedded Linux device based on an Atmel SAMA5D3x ARM-A5 processor. Normally, embedded Linux boxes will boot up off of flash memory or an SD card. But if you’re messing around, or just want to sidestep normal operation for any reason, you could conceivably want to bypass the normal boot procedure. Digging around in the chip’s datasheet, there’s a way to enter boot mode by soldering a wire to pull the BMS pin. As [Sami] demonstrates, there’s also a software way in, and it makes use of mmap, a ridiculously powerful Linux function that …read more http://pje.fyi/NjFwvQ