Developed On Hackaday: The Current Project State

February 11, 2014 by Mathieu Stephan 22 Comments

It has been quite a while since we updated our readers with the current state of the Mooltipass, the offline password keeper project developed by the Hackaday staff and community.

A few weeks ago we presented you the designs that our mechanical contributors had thought of. We organized a poll to get a feeling of what the favorite designs may be and around one thousand people expressed their opinions. The first three favorite designs with their corresponding votes were:

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Introducing The SquareWear Mini, With Its Chainable Color LED Matrix

February 10, 2014 by Mathieu Stephan 8 Comments

[Ray] just tipped us about his latest project: the SquareWear Mini, which basically is an improved version of the SquareWear 2.0 that we featured a month ago. For our readers that may have missed it, the SquareWear is essentially a wearable Arduino platform running at 3.3V and 12MHz. Both versions are based on an ATMega328 microcontroller running the V-USB library to provide USB connectivity, put together with diverse onboard peripherals.

As you can see in the picture above, the Mini includes 2 N-MOSFETs, one temperature sensor, one light sensor, a 16KB EEPROM memory, one buzzer, a one cell LiPo battery connector together with one charging controller, and finally a power switch (USB/battery). It is supposed to be 25% smaller than the SquareWear 2.0 and is optimized to work with a WS2812B-based 5×7 RGB LED matrix that [Ray] also designed. The latter can easily be cascaded in X/Y directions with other LED matrices in order to expand the overall display.

At last, [Ray] created a software to design animations and upload them to the SquareWear . A presentation video of the complete system is embedded after the break and you can download all the design files on GitHub.

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Sniffing And Decoding Bluetooth LE Advertising Packets And NRF24L01+ Comms. For Under $30

January 22, 2014 by Mathieu Stephan 9 Comments

[Omri] just documented his journey to sniff and decode the protocol used by the popular NRF24L01+ transceiver off the air for very cheap. As he was designing a mesh network code and needed a way to monitor/debug the overall network performance, [Omri] decided to look for some RF hardware.

We’re sure that most of our readers are familiar with Software Defined Radio (SDR), which not so long ago became popular when some engineer discovered hidden registers inside Realtek RTL2832U chip, allowing many DVB-T dongles to be converted into RF listening devices. Unfortunately for [Omri], most of them have a maximum listening frequency of 2.2GHz, while the NRF24L01+ emits at 2.4GHz. The solution? Buy a 2.2-2.4GHz antenna from Aliexpress with a low-noise block downconverter (LNB), used for a Multichannel Multipoint Distribution Service (MMDS). The LNB therefore takes the 2.2-2.4GHz signal and downconverts it to around 400MHz, allowing any RTL-SDR-compatible DVB-T dongle to listen to the NRF communications. A program was then written to decode the RF signal and output the sniffed data in realtime.

Final Key : A Mooltipass-like Device

January 21, 2014 by Mathieu Stephan 5 Comments

Since the Hackaday community started working on our offline password keeper, Mooltipass, we’ve received several similar projects in our tips line. The Final Key may be the most professional looking one yet. Similarly to the Mooltipass, it is based on an Atmel ATMega32U4 but only includes one button and one LED, all enclosed in a 3D printed case.

The Final Key is connected to the host computer via USB and is enumerated as a composite Communication Device / HID Keyboard, requiring windows-based devices to install drivers. AES-256 encrypted passwords are stored on the device and can only be accessed once the button has been pressed and the correct 256 bit password has been presented through the command line interface. Credentials management and access is also done through the latter. Unfortunately, the Arduino source code can’t be found on [cyberstalker]’s website, so if you see interesting features that you would like to be integrated in Mooltipass you may send us a message to our Google Group.

Developed On Hackaday: The Designs

January 20, 2014 by Mathieu Stephan 34 Comments

We know that many of our readers have been impatiently waiting to discover what the Hackaday community-developed offline password keeper project will look like. Today we present you several designs that our mechanical contributors came up with and we will ask you to give your opinion about them. Obviously these are just preliminary cases that may evolve along the way, but we will only produce the electronics for the designs you prefer.

All the designs are embedded after the break, with a multiple-choices poll to express your interest. You may also want to join the Mooltipass Google Group in case you’d want to talk about the designs in more depth or meet their creators. On the firmware side, I just finished soldering many mooltipass prototypes that will be shipped in the coming days to our firmware developers. As you may have noticed, this project is gaining speed!

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Making A 20dB Low Noise Amplifier For A 400MHz Radio

January 19, 2014 by Mathieu Stephan 21 Comments

[Will] recently tipped us about a 400MHz Low Noise Amplifier (LNA) module he made. His detailed write-up starts by explaining the theory behind an amplifying chain. Assuming a 50 Ohm antenna system receives a -70dBm signal, the total peak to peak voltage would be less than 200uV (.0002 volts). If the first amplifying stage doesn’t consist of an LNA, then the added noise would later be amplified by the other elements of your system.

[Will] then detailed how he picked his LNA on Digikey, mainly by looking for one that had a less than 1dB Noise Figure. His final choice was the Sky65047: a small budget-priced 0.4-3.0GHz low noise amplifier with a theoretical gain of 20dB at 400MHz. He made the PCB you can see in the picture above, removing the soldermask on the signal path in order to lower the permitivity. Because of a few mistakes present in the application note, it took [Will] quite a while to get his platform up and running with a 20dB gain but a 4.5dB NF. He also measured the input return loss using a directional coupler, which ended up being quite close to the datasheet’s 14dB number.

Three Axis Position Indicator With Digital Calipers

January 19, 2014 by Mathieu Stephan 22 Comments

[Malte] just finished a little project for his Wabeco F1200 milling machine: a compact external display for three digital sliding calipers (Translated from German). As you may have already guessed, [Malte] was lucky enough to be able to fit disassembled calipers onto the machine and use them for positioning. Before embarking on this adventure, he noticed that there were similar projects present on the internet, but all of the calipers used had different data interfaces and protocols. The calipers that [Malte] bought have a mini USB connector, even though the interface itself isn’t USB. As he couldn’t find any information on that interface, he turned to his oscilloscope to decode the protocol.

[Malte] then built an AVR-based platform that reads out the three calipers and shows the position data on the dot matrix LCD shown above. The AVR firmware is written in a mixture of Basic and assembler language. The source code, schematics, and other resources can be downloaded from the project’s web page. We are impressed on the professional aspect of the final result.

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