Running the Linux kernel on a DE0-nano FPGA board

[Mike] has been filling up a rather intense wiki entry outlining how to run uClinux on a DE0-nano FPGA board. This is an inexpensive dev board that will run you somewhere between $80 and $100. Right off the bat he goes into a hefty list of the reasons that this is a foolish activity. To name a few: Once you’ve complete the build the device will be tethered for reboot.  This board doesn’t have Ethernet hardware and TCP/IP is one of the beast features of the uClinux kernel. And the FPGA tools are closed-source, which doesn’t often mesh with the ideals of Linux developers. But we still like to see what it really takes to get these large-scope firmware builds to compile and load correctly.

After his preamble you’ll find three main chunks. The first deals with setting up the toolchain on Fedora 14. From there, he installs packages necessary for cross-compiling, pulls down the source packages, and gets to work. Once the kernel is compiled and running on the FPGA [Mike] goes on to show you how to build out a simple hardware add-on in the form of a couple of LEDs connected to extra FPGA pins. The final portion of the wiki details rolling support for toggling the LEDs into the software distribution.

CV Sequencer with a TV out

[gijs] sent in the control voltage sequencer he’s been working on that uses the TVout Arduino library to provide a graphical interface.

The sequencer doesn’t produce any sound on its own. Instead, it outputs a Control Voltage so other synths can be sequenced with [gijs]‘ TVSCV. Before MIDI came around, CV was the standard to connect synthesizers and drum machines together. Even today, a lot of boutique synths have at least one jack for CV. [gijs]‘ build is really interesting because of the user interface – the TVout Arduino library was used in conjunction with a tiny CRT to change values, timing and speed of the CV output. The TVSCV is able to sequence two different channels of CV at 10 bit resolution with 16 steps per bank.

From the video after the break, the TVSCV sounds like it can produce what would be the trippiest soundtrack ever conceived for an Atari or NES game. It’s a great bit of kit, especially when connected to an Atari punk console or a TR-808 and a glitch delay.

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Amazing RGB POV clock

rgb_pov_propeller_clock

We’re no strangers to POV time pieces around here, but something about them never gets old. Whether they use a ring of LEDs to draw clock hands, or an intricately cut HDD platter to replicate LCD segments, we love seeing them. [David] sent in this hard drive POV clock built by a fellow named [Kly], and it’s just beautiful.

[Kly’s] “Propeller” POV clock is named as such due to the design of the circuit board. The board is mounted on the HDD spindle, rotating much like an airplane’s propeller. The construction details are sparse, but from what we can find, it is based around a PIC32MX microcontroller, which is used to control the 66 SMD RGB LEDs mounted on the circuit board.

As you can see in the video below, the tightly packed LEDs result in some pretty amazing visuals.

Aside from watching the video below, be sure to swing by his Youtube channel for a handful of videos showing RGB POV clock in action.

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They may be for developing countries, but we want a concrete lathe

At the 2009 Ghana Maker Faire, [Pat Delany] met a young carpentry student that saved for three months to buy a cheap Chinese wood plane. He was confounded by this distribution of resources, so [Pat] created the Concrete Lathe project that aims to get useful machine tools out to where they’re needed most.

The idea for concrete machine tools came out of the US involvement in World War I. America had been staunchly isolationist before committing to the war, and production of arms did not match the needed output. A man named L.I. Yeomans came up with the idea of building concrete lathes to produce artillery shells for the war effort.

Of course, the concrete lathe project is a bit more peaceful in its intentions. The concrete lathe is meant to be a cheap machine tool for developing nations. Both the concrete lathe and the Multimachine are meant to be built cheaply using scrap materials, reduce training time for machinists, and create other machine tools in a Reprap-like biological distribution.

There’s a ton of documentation on the concrete lathe wiki like the bed instructions torn from the pages of Ikea instructions, and the thread follower. While they’re still a lot of work and testing to be done, giving some manufacturing capability to those who need it most is a pretty noble cause.

Thanks [Rob] for sending this one in.

Arduino boards control cheap clockworks via coil injection

Here’s a couple of clocks that use Arduino boards to control inexpensive clockworks. The concept is quite simple, and perhaps best outlined by [Matt Mets'] article on the subject. As it turns out, these clockworks are driven by a coil, forming a device that is quite similar to a stepper motor. If you solder a wire onto each end of the electromagnetic coil and hook those to a microcontroller, you can alter the speed at which the clock ticks. Just drive one pin high and the other low, then reverse the polarity for the next tick.

The clock you see on the right (translated) is a store-bought cheapy. The Arduino barely visible at the bottom of the image is sending pulses once every second. But as you can see in the video after the break, holding down a button will fast-forward through time. [Sodanam] posted his code as well as pictures of the hardware hack itself.

To the left is a horse of a different color. It’s a clock modeled after the Weasley household clock from the Harry Potter books. The clockwork trick is the same, but the Arduino uses GPS data and NOAA weather information to set the status.

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Turn your Wireless Keyboard into a MAME Controller!

For those of you that have a wireless keyboard laying around, you might be tempted to turn it into something else, like a wireless MAME controller. For those not familiar with it, MAME stands for “Multiple Arcade Machine Emulator” and is generally used to run older arcade games on a computer.

Encoders are available for this purpose, however, intending to save some money, and having an unused wireless keyboard, I decided to try to make one myself.  As far as I know there are no wireless encoders available for this purpose, so that was part of the motivation for trying this.

In this post I go over my mechanical design for the cabinet as well as the electrical process of going from keyboard to MAME controller. I did eventually get the thing working, but if more than a couple buttons were pressed simultaneously, some presses were omitted. The conclusion I eventually came to was that it was better to use an encoder to control everything. Not wireless, but much more reliable. If I absolutely needed a wireless controller in the future, I would think modding an actual wireless controller (or two) in a similar manner would have worked better for my purposes.

DIY breadboard modules for easy prototyping

[Rajendra] got tired of building the same basic circuits time and again on the breadboard. He decided to build some simple, modular circuits on protoboard and make them easy to interface with the breadboard. As you can see, he ended up with seven modules that make prototyping faster and easier.

At first glance some might not seem all that beneficial. For instance, making a board for an 18-pin PIC microcontroller into a single-in-line form factor would seem like you’re actually wasting breadboard space when compared to the DIL package of the chip. But consider that the oscillator and its capacitors, reset button, and programming header are also on the breakout board and will not have to be built in place. There are also several I/O boards, one with five buttons, another with an LED bar graph, and a set of LEDs with a SIL resistor package on-board. These modules can be plugged into a breadboard and wired up with jumper wires, or connected directly to the same rows as the microcontroller module.

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