[Vsergeev] tipped us about a neat Cortex-M0 based development board with a total BoM cost under $15. It’s called the ARM Bare Metal Widget (ARM-BMW), focuses on battery power, non-volatile storage and debuggability.
The chosen micro-controller is the 50MHz NXP LPC1114DH28 which provides the user with 32kB of Flash, 8kB of SRAM, a 6 channel ADC and I2C/SPI/UART interfaces among others. The ARM-BMW contains a 2Mbyte SPI flash, an I2C I/O expander, several headers for expansion/debug purposes, 4 LEDs, 2 buttons, 2 DIP switches and finally a JTAG/SWD header for flashing and debugging. As you can see in the picture above you may either populate your own HC49UP crystal or use the internal 12MHz RC oscillator.
The platform can be powered using either a USB cable or a LiPo battery. As you can guess it also includes a much-needed battery charger (the MCP73831T) and a switched capacitor DC/DC converter to supply 3.3V. You may find all the files on the hardware or software repositories.
Homemade reflow ovens are a great inexpensive way to quickly solder multiple prototypes at once. [Andy] may just have built one of the best ones we’ve featured so far on Hackaday. For his project a £25 1300W 12litre halogen oven was chosen because of its low cost and fast heating time, the latter being required to follow typical reflow profile ramp-up stages.
To control the AC power [Andy] first bought a chinese Fotek Solid State Relay (SSR) on ebay, which was quickly replaced by an american one after reading concerning reports on the internet. He then made the same ‘mistake’ by buying the typical MAX6675 thermocouple-to-digital converter from the same website, as he spent much time understanding why the measurements were wrong when the IC was just defective. His final build is based around a 640×360 TFT LCD that he previously reverse engineered, the cortex-M0 STM32F051C8T7, a SPI flash, some power regulators and buttons. The firmware was written in C++ and we’ll let our readers visit [Andy]’s page to see how well his oven performs.
Looking at the looping GIF above you’re probably thinking, oh, another hard drive POV setup… Well… Not quite.
This is one of [Dev’s] latest projects, and it is a planetary map that shows the angular positions of all 8 of the major celestial bodies from any given date between 1800 and 2050. It’s also capable of showing analogue clock hands, the phases of the moon, and other simple graphics.
The main unit is a hard disk, but [Dev] milled off many of the features on it to give it a more exposed, purpose-built look. He designed the LED bearing PCB from scratch using EagleCAD, which sits on the back of the drive, with the spindle poking through. It has 8 rings of 5 surface mounted LEDs, which shine through opaque plastic diffuser rings that he printed using Shapeways — they feature small recesses to fit snugly on the board over the LEDs. On the top level is a 1mm thick black disc of some unknown material that [Dev] had sitting around, which now has 8 holes machined into it in the exact position of the LEDs.
A Cortex-M0 drives the LEDs using an LPCXpresso board which allows the LEDs to sit across only one byte of a hardware I/O port. On the software end, each rotation of the disk is segmented into three hundred and sixty 1 degree slices. This system allows him to achieve a circular resolution of 8×360 pixels at 25 frames per second. Not bad for a persistence of vision device!
Stick around after the break to see the rather entertaining demo video of the device.
Continue reading “Persistence of Vision Planetary Map”
The new crop of ARM Cortex M0/M3/M4 microcontrollers have a lot of interesting features for developers. In addition to supporting drag and drop programming via USB, the same hardware can also be used as a debugger. Setting breakpoints and inspecting memory at any point in the code is a wonderful feature, but not all the new ARM dev boards we’ve seen support this feature.
The folks over on SimpleCortex have a solution to this problem, but they need your help. To get their CMSIS-DAP hardware working with Open Source tools, they’re looking for a few good programmers and hardware developers to build a toolchain.
Right now, the hardware only works with Keil development tools. A closed source development environment is no good to anyone, so if you have some experience writing drivers and such, send the guys at SimpleCortex an email. They’ll give you a free board in return for a contribution to building an open source ARM toolchain.
Common sense requires us to mention that you should probably only send these guys an email if you actually plan on working on this problem. Still, it’s a great opportunity to contribute to open hardware.
We’re impressed by the ARM prototyping board which [Danjovic] is showing off. He proves that in this day of ever shrinking packages it’s still possible to make your own development tools with protoboard and a soldering iron.
To tell you the truth, if he had designed and etched his own board we probably wouldn’t have featured it. But he didn’t need to spend time on the layout, etching, and reflow. Instead it’s just some enamel wire and a lot of patience. The patience is because the NXP ARM Cortex-M0 chip comes in a HVQFN package. We’re not entirely sure about the HV part (the package alphabet was not entirely clear on this) but QFN means Quad Flat No-Lead. That means no legs on the chip. So [Danjovic] glued it upside down and soldered point-to-point to break out all of the pins.
The top side of the board has a bootloader button, reset button, power regulation, and a crystal oscillator. He doesn’t mention what bootloader he’s using, but a Nokia USB cable gives him the connectivity to push his programs onto the chip.
The days of the 8 bit Arduino may be quickly coming to a close. Sure, there will always be a place for AVRs in blinking LEDs and turning on relays, but for doing anything cool – playing MP3s, driving LCD displays, or running a CNC machine – you need the power of a 32 bit chip. [Brian Carrigan] put up a great tutorial on getting started with these bigger, more powerful micros and moving beyond what is possible with an 8 bit PIC or AVR.
These new 32 bit chips are much more powerful, but aren’t exactly hobbyist friendly. Most of the ARM chips we’ve found are stuffed into very fine pitch QFN or QFP packages that require a reflow oven to solder to a board. In fact, we can only find one through-hole Cortex M0 chip that is suited for breadboard development. This doesn’t make it easy to whip up a circuit in a few hours, so builders needing a very powerful microcontroller will be more dependent on dev boards.
Already there are a good number of ARM-based 32 bit dev boards available including the offerings from Leaf Labs, the extremely inexpensive STM Discovery board, Kinetis KL25Z Freedom Board, the outrageously powerful BeagleBone, and the perpetually delayed Arduino (over) Due.
None of these boards are particularly new developments; they’ve all been around the block once or twice. However, there are many more options for 32 bit development than the current 8 bit PIC and AVR holy war. We’re going to turn the comments over to Hackaday readers with the following questions: what supersized dev board are you rolling with? What’s good for a beginner, and what should they watch out for?
The STM32 Discovery boards are nothing new, we’ve looked at them several times. But the newest sibling in the line might be just the thing to make the leap from your steadfast 8-bit projects. We got our hands on it and recorded a video review.
The STM32F0-Discovery gives you a programmer and ARM Cortex-M0 chip all on one convenient board. The top portion is the ST-Link V2 programmer, and includes jumpers and a programming header which let it easily program off-board chips.
The included microcontroller is an STM32F051R8T6 which includes 64kb of program memory and 8kb of RAM. Coming in at $1.80-3.77 in single units and in a hand-solderable LQFP package this raises an eyebrow for our future projects. It has an 8 MHz internal oscillator with 6x PLL which means you can run at 48 MHz without an external crystal (check out [Kenneth Finnegan’s] PLL primer if you don’t know what this is).
The only thing holding us back is the development environment. ST provides everything you need if you’re on Windows, but we want a Linux friendly solution. We know other Discovery boards have worked under Linux thanks to this project. This uses the same ST-LINK V2 so it should work as well. If you want one of your own head over the ST page to see if they’re still giving away samples. There should be a button labeled “Register for your FREE KIT”.