Programmable Lithium Charger Shield For Arduino

November 19, 2014 by Marsh 12 Comments

Surely you need yet another way to charge your lithium batteries—perhaps you can sate your desperation with this programmable multi (or single) cell lithium charger shield for the Arduino?! Okay, so you’re not hurting for another method of juicing up your batteries. If you’re a regular around these parts of the interwebs, you’ll recall the lithium charging guide and that rather incredible, near-encyclopedic rundown of both batteries and chargers, which likely kept your charging needs under control.

That said, this shield by Electro-Labs might be the perfect transition for the die-hard-‘duino fanatic looking to migrate to tougher projects. The build features an LCD and four-button interface to fiddle with settings, and is based around an LT1510 constant current/constant voltage charger IC. You can find the schematic, bill of materials, code, and PCB design on the Electro-Labs webpage, as well as a brief rundown explaining how the circuit works. Still want to add on the design? Throw in one of these Li-ion holders for quick battery swapping action.

[via Embedded Lab]

RTL SDR As A Spectrum Analyzer

November 19, 2014 by Brian Benchoff 24 Comments

RTL-SDR, the USB TV tuner turned software-defined radio is an amazing device, capable of listening to nearly anything from 25MHz to 1750MHz, fits in your pocket, and costs about $20. Even more astonishing is that it’s also a kinda-okay spectrum analyzer. [Kerry D. Wong] tested out one of these USB TV tuner, and the results are exactly what you would expect: it lacks a little precision, and sampling bandwidth is only a tiny bit terrible, but it does work.

A stock USB TV tuner doesn’t come with a connector that would normally be used for spectrum analysis. A BNC connector can be easily attached, as can a terminator to match the 75Ω impedance of the SDR. This isn’t really necessary; the frequencies being measured are low enough that you can get away without one.

As far as software goes, [Kerry] first pulled out the usual suspects of the SDR world; rtlsdr-scanner distorted the measured spectrum, as did a lot of other SDR receivers. Gqrx SDR was the first one that worked well, but the king of this repurposing of USB TV tuners was OSMOCOM. There’s a huge number of tools for spectrum analysis right out of the box with this package.

How did the RTL SDR fare as a spectrum analyzer? Feeding some stuff in from a signal generator, [Kerry] discovered the LO in the RTL SDR was off by a hair. Also, OSMOCOM only measures amplitude in dB, not the dBm found in every other spectrum analyzer ever made. By measuring a 0 dBm signal whatever value displayed can be shifted up or down.

So, does it work? Yes, it does. If, for some reason, you need a spectrum analyzer now, can you use this? Yep. Pretty cool.

Measuring The Length Of WS2812 Strips

November 19, 2014 by Ethan Zonca 12 Comments

[Tim] discovered a simple way to measure the length of WS2812 addressable LED strips from a microcontroller. This is great for any project that can have an arbitrary length of addressable LED strip attached to it.

The simplest (and perhaps most reliable) way to measure strip length is by feeding the serial output pin of the end of the strip back to the microcontroller. The microcontroller keeps clocking bits into the strip until it receives data from the end of the strip. [Tim] didn’t want to run an additional signal to the end of his strip, so he found another solution.

[Tim] used the ADC of his microcontroller (an ATtiny) to measure supply voltage droop as LEDs are turned on. Each LED draws around 60mA at full brightness, so [Tim] sequentially turned on each LED and watched the ADC for slight voltage changes. If the voltage changed, there must be an LED at that address. [Tim] does note that this method is extremely dependent on the power supply used and only works on short strips. Check out his blog post for more details.

Extreme Repair Of An All-in-One PC

November 18, 2014 by Adam Fabio 11 Comments

While browsing a local auction site, [Viktor] found himself bidding on a beat up Lenovo A600 all-in-one PC. He bid around $50 and won. Then came the hard part – actually making the thing work. The front glass was cracked, but the LCD was thankfully unharmed. The heat pipes looked like they had been attacked with monkey wrenches. The superIO chip’s pins were mangled, and worst of all, the MXM video card was dead.

The first order of business was to fix the superIO chip’s pins and a few nearby discrete components which had been knocked off their pads. Once that was done, [Viktor] was actually able to get the computer to boot into Linux from a USB flash drive. The next step was bringing up the display. [Viktor] only needed a coding station, so in addition to being dead, the video accelerator on the MXM wasn’t very useful to him. The Lenovo’s motherboard was designed to support video on an MXM card or internal video. Switching over meant changing some driver settings and moving a few components, including a rather large LVDS connector for the display itself. A difficult task, compounded by the fact that [Viktor’s] soldering tools were a pair of soldering guns that would be better suited to fixing the bodywork on a ’57 Chevy. He was able to fashion a hot wire setup of sorts, and moved the connector over. When he was done, only one tiny solder bridge remained!

The end result is a new coding battle station for [Viktor] and a computer which was a basket case is saved from the landfill. If you like this hack, check out [Viktor’s] low power PSU, or his 1 wire network!

‘Nutclough’ Circuit Board Design Is Stylishly Amplified

November 18, 2014 by Sarah Petkus 17 Comments

Though there is nothing wrong with the raw functionality of a plain rectangular PCB, boards that work an edge of aesthetic flare into their layout leave a lasting impression on those who see them. This is the philosophy of circuit artist [Saar Drimer] of Boldport, and the reason why he was commissioned by Calrec Audio to create the look for their anniversary edition amplifier kit. We’ve seen project’s by [Saar] before and this ‘Nutclough18’ amplifier is another great example of his artistic handy work.

For the special occasion of their 50th anniversary, Calrec Audio contacted [Saar] requesting he create something a bit more enticing than their standard rectangular design from previous years. With their schematic as a starting point, [Saar] used cardboard to mock-up a few of his ideas in order to get a feel for the placement of the components. Several renditions later, [Saar] decided to implement the exact proportions of the company’s iconic Apollo desk into the heart of the design as an added nod back to the company itself. In the negative space between the lines of the Apollo desk there is a small perforated piece depicting the mill where the Calrec offices are located. The image of the mill makes use of different combinations of copper, silk and solder mask either absent or present to create shading and depth as the light passes through the board. This small piece that would have otherwise been removed as scrap can be snapped off from the body of the PCB and used as a commemorative keychain.

With the battery and speaker mounted behind the completed circuit board, [Saar’s] design succeeds in being a unique memento with a stylish appeal. There is a complete case study with detailed documentation on the Nutclough from cardboard to product on the Boldport website. Here you can also see some other examples of their gorgeous circuit art, or checkout their opensource software to help in designing your own alternative PCBs.

Using MIDI And Magnets To Produce Tones With Tines

November 18, 2014 by Sarah Petkus 18 Comments

Normally you’d expect the sound of a pipe organ to come from something gigantic. [Matthew Steinke] managed to squeeze all of that rich melodic depth into an acoustic device the size of a toaster (YouTube link) which uses electromagnetism to create its familiar sound.

[Matthew ’s] instrument has a series of thin vertical tines, each coupled with a small MIDI controlled electromagnet. As the magnet pulses with modulation at a specific frequency, the pull and release of the tine causes it to resonate continuously with a particular tone. The Tine Organ is capable of producing 20 chromatic notes in full polyphony starting in middle C and can be used as an attachment to a standard keyboard or a synthesizer app on a smart phone. The classic style body of the instrument is made out of mahogany and babinga and houses the soundboard as well as the mini microcontroller responsible for receiving the MIDI and regulating the software oscillators sending voltage to the magnets.

[Matthew’s] creation is as interesting to look at as it is to listen to, so I’d recommend checking out the video below to hear the awesome sound it produces:

Continue reading “Using MIDI And Magnets To Produce Tones With Tines” →

Hackerspace Tours: MuCCC

November 18, 2014 by Brian Benchoff 9 Comments

Our trip to Germany wouldn’t be complete without a trip to a proper European hackerspace, and the Munich Chaos Computer Club was more than accommodating in allowing us to invade their space.

Before even walking in the door, you’re greeted with one of the coolest displays you’ve ever seen. Half of the front of their building is a gigantic flipdot display. It’s astonishing in person, and although no dots were flipped during our visit, we can imagine the noise would be deafening. Simply awesome.

Walking in the door, you’re greeted with the general meeting area, conference room, couches, and a Twilight Zone pinball machine. The machine didn’t quite work when we arrived, but within five minutes, [Sprite_TM] was behind the backglass and had everything fixed within an hour.

The back room and basement have the usual assortment of tools – a 3D printer, CNC, lathe, and electronics workbench. If you need a key made, head to the basement. You’ll also find an ATM in the basement. The story with that is that the news station in Munich wanted to do a story on how easy it was to get USB access to the Windows system in an ATM. The station couldn’t do it – but they faked it – and put the ATM up on eBay. Not much money later, the ATM found its way to the space’s basement.

MuCCC is more than just a space with tools, though: in the european hackerspace tradition, there are frequent presentations and talks that would fit in at an academic conference. Last Tuesday, [nicolas] presented a few techniques to protect cryptographic keys from physical integrity attacks, i.e. an evil maid attack or a SWAT team invading your router closet. It’s a daemon that listens to an AVR loaded up with sensors through a GPIO pin. If there is physical intrusion in the device – barometric pressure or light – keys resident in memory can be erased.

You can check out a gallery of pics from the space below.

The stores of Club Mate. There was also a vending machine.

Components

Flip dot display in a junk box.

Iambic keyer

This test equipment was donated, but it’s still amazingly good

No, that’s not a Darwin. It’s close, though, and the only printer of this design I’ve seen at a hackersapce

Keys

There’s an ATM in the basement. Apparently, a news station in Munich bought an ATM to demonstrate how easy it is to crack. The news station couldn’t crack it. It was then sold on eBay and wound up at the space. Yes, you can now play Solitaire on it.