A hard drive crash, and some other happenings that aren’t entirely clear to us, led [Devbisme] to put in a parts order. As he wanted to make the most of his shipping costs, he decided to fill out the order with parts that he’ll use eventually. He’s been working with surface mount designs and wanted to move from using resistors with 0805 packages to the 0603. Having nothing on hand, he devised a way to account for almost all standard values with the fewest number of different resistors.

That’s a mouthful, but what he actually did was figure out what combinations of resistors can best be wired in parallel to achieve a different standard resistance value. This way, if he doesn’t have a specific value he can solder one 0603 surface mount resistor on top of another one to get there. He ended up writing a Python program to best calculate this set of values. It came up with a set that lets him synthesize 159 of the 168 standard resistor values within +/- 4% using just 19 actual resistor values. His method requires anywhere from one to three resistors to get to each value. Soldering three 0603 packages on top of each other might not be the most fun, but it makes for easy parts inventory management.

[Michael] took a battery charger meant to be connected to mains power and converted it to work with a solar panel. This was a traditional 4 cell charger which charges the batteries in pairs. He kept that functionality, but added USB charging with a special over-current feature. That’s because his Android phone has a fast and slow USB charging mode. The slow mode makes sure that it draws 500 mA or less to stay within USB specifications. But the fast mode draws more current when the phone detects that the USB connection is attached to a wall charger. [Michael] added a switch that patches a pull-up resistor to the data line, signaling to the phone that it’s okay to switch to fast charging mode.

As for the power supply itself, you can see that [Michael] snapped off the part of the circuit board that housed the original regulator. He’s added his own 5V switching regulator which offers a wide input voltage range. This is connected to two banana plug sockets which can be connected to the solar panel.

[Patrick] was prepping for some future projects he had in mind, for which he will need a simple 2D array of addressable LEDs. While it is certainly possible for him to build his own LED array and control hardware, he thought he would try out some off the shelf products to see if something might fit his needs.

He picked up a strip of addressable RGB LEDs from Adafruit, and while they worked very well, they were a bit too pricey for the amount of LEDs he knew he would need. He picked up a strip of similar LEDs without PWM capabilities built-in, and gave those a spin – they worked well enough, so he got to work building his LED array.

While LED strips might not jump right out as the best way to make an LED array, they can be easily cut and rearranged without any issue, provided you solder in a couple of wires to connect the disjointed strips. [Patrick] did just that, and wrote a small Arduino library that allows for easy control of the grid.

We’re not sure if he plans on scaling these arrays any larger than 8×8, but we are definitely interested to see what he has in store for them.

Check out a quick video of his LED array in action below.

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[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.

[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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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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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.

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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