Developed on Hackaday: Need Card Art — Who Likes to Draw?

Our offline password keeper project (aka Mooltipass) is quite lucky to have very active (and very competent) contributors. [Harlequin-tech] recently finished our OLED screen low level graphics library which (among others) supports RLE decompression, variable-width fonts and multiple bit depths for fonts & bitmaps. To make things easy, he also published a nice python script to automatically generate c header files from bitmap pictures and another one to export fonts.

[Miguel] finished the AES encryption/decryption schemes (using AES in CTR mode) and wrote an awesome readme which explains how everything works and how someone may check his code using several standardized tests. We highly encourage readers to make sure that we didn’t make any mistake, as it was one of you that suggested we migrate to CTR mode (thanks [mate]!).

On the hardware side, we launched into production the top & bottom PCBs for Olivier’s design. We’re also currently looking for someone that has many Arduino shields to make sure that they can be connected to the Mooltipass. A few days ago we successfully put the Arduino bootloader inside our microcontroller and made the official Arduino Ethernet shield work with it.

Finally, as you may have guessed from the picture above our dear smart card re-sellers can pretty much print anything on them (these are samples). If one of you is motivated to draw something, please contact me at mathieu[at]hackaday.com!

On a (way) more childish note, don’t hesitate to give a skull to the mooltipass on HaD projects so it may reclaim its rightful spot as “most skulled“.

Designing a WakeUp Light

[Akhil] and his wife recently finished their WakeUp Light project. As the name suggests, this kind of morning alarm uses light to wake you up in the morning. The main constraints when starting this relationship-strengthening adventure were cost, ability to work with any table lamp, and having a simple but effective control interface, all while keeping all the design open. The created platform (put in the wooden box shown above) is built around a Stellaris Launchpad (ARM Cortex M4 based) and uses an AC dimmer circuit found in this instructable. For our readers interested in those, [Akhil] mentions two very interesting articles about their theory of operation here and here.

An Android application has been made to set up all the alarm parameters, which uses the phone’s Bluetooth to communicate with the (well-known) HC-05 Bluetooth transceiver connected to the Launchpad. For safety, the current design also includes an LM4876 based audio amplifier connected to the microcontroller’s PWM output. The next revision will integrate a Digital to Analog Converter and an SD-Card slot for better quality and music diversity. A presentation video is embedded after the break and you can find the official repository at GitHub.

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Copper Oxide Thermoelectric Generator Can Light An LED

On Hackaday, we usually end up featuring projects using building blocks (components, platforms…) that can be bought on the market. We however don’t show many hacks that rely on basic physics principles like the one shown in the picture above.

In the video embedded below, [nylesteiner] explains that copper oxide can be formed when heating a copper wire using a propane flame. When two oxidized wires are placed in contact with each other, an electrical current is produced when one wire is heated much hotter than the other. The trade-off is that the created thermocouple generates a small voltage but a ‘high’ current. However, when you cascade 16 junctions in series you can generate enough voltage to light up an LED. Even though the complete system isn’t particularly efficient at converting heat into electricity, the overall result is still quite impressive in our opinion. We advise our readers to give a look at [nylesteiner]‘s article and blog to discover his interesting adventures.

 

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Monitoring your Gas Consumption with a JeeNode and a nRF24L01+

[Sven337] just blogged about a gas consumption monitoring setup he finished not long ago. As his gas meter was located outside his apartment and nowhere near any electrical outlet, a battery-powered platform that could wirelessly send the current consumption data to his Raspberry Pi was required. His final solution therefore consists of a JeeNode coupled with the well known nRF24L01+ wireless transmitter, powered by 3 supposedly dead alkaline batteries.

[Sven337] carefully looked at the different techniques available to read the data from his meter. At first he had thought of using a reflective sensor to detect the number 6 which (in France at least) is designed to reflect light very well. He then finally settled for a magnetic based solution, as the Actaris G4 gas meter has a small depression intended for magnetic sensors. The PCB you see in the picture above therefore has a reed sensor and a debug LED. The four wires go to a plastic enclosure containing the JeeNode, a couple of LEDs and a reset switch. Using another nRF24L01, the Raspberry Pi finally receives the pulse count and reports it to an eeePC which takes care of the storage and graphing.

Meet Lynx, a (costly) Offline Password Keeper

Maybe because he didn’t want to wait for the Mooltipass to be produced, [davidhend] built himself his own offline password keeper, named Lynx.

It is based around an Arduino Pro 328, a 2.8″ TFT touch screen, an RFID card reader, an FTDI basic breakout and finally a li-ion battery. Lynx is therefore self-powered and uses an RFID card to later read the XOR-encrypted passwords located in a SD card. A USB serial connection is used to send the passwords to the computer, which also charges the battery. The current BoM cost is around $220 but we’re quite sure it can be made for much cheaper when not using pre-made boards. Looking at the official GitHub repository tells us that the XOR key is stored inside the microcontroller and that Lynx checks the RFID card code to allow encryption/decryption.

On a side note, we recently published a FAQ on the official Mooltipass GitHub. You’re welcome to let us know what questions we may have forgotten.

GEVCU – an Open Generalized Electric Vehicle Control Unit

At Hackaday we’re very happy to see the increasing number of open hardware devices that appear everyday on the internet, and we’re also quite thrilled about open-source electric cars. Pictured above is the GEVCU, an open source electric vehicle control unit (or ECU). It is in charge of processing different inputs (throttle position, brake pressure, vehicle sensors) then send the appropriate control commands to electric motor controllers (aka inverters) via CAN bus messages or digital / PWM signals.

The project started back in December 2012 and was originally based on an Arduino Due. Since then, the GEVCU went through several revisions and ultimately a complete custom board was produced, while still keeping the Cortex M3 ATSAM3X8E from the Due. As you may have guessed, the board also includes a Wifi transceiver so users may adjust the ECU parameters via a web based platform. All resources may be downloaded from the official GitHub.

Listening to Electromagnetic Interference with a RTLSDR Dongle

Being curious by nature, [Marios] decided to see what kind of radio-frequency emissions may be generated by an Arduino connected to a simple breadboard wire, and more importantly try to pick them up using a RTLSDR dongle. Electromagnetic interferences are disturbances that affect electrical circuits due to either electromagnetic induction or electromagnetic radiation. Before going into the market, all electrical devices are thoroughly checked for unwanted electromagnetic emissions so they usually aren’t obvious suspects when such problems arise.

Using the Arduino embedded PWM controller in fast PWM mode and by manipulating the duty cycle, he actually managed to create a primitive form of amplitude modulation and was able to transfer a very simple audible signal at several frequencies up to 1.75GHz. Embedded after the break here is video of the system at work.

As a side note, did you know that during the solar storm of 1859 the EMI were so strong that the telegraph operators received several shocks? Pipelines maintenance systems also have to be aware of such events, that can lead sensors to provide inaccurate results.

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