Developed on Hackaday: Security and Arduino Compatibility


Some of our readers noticed that the Hackaday community open-source offline password keeper (aka Mooltipass) has two incompatible characteristics: being secure and Arduino compatible.

Why is that? Arduino compatibility implies including a way to change the device firmware and accessing the microcontroller’s pins to connect shields. Therefore, some ill-intentioned individuals may replace the original firmware with one that would log all user’s inputs and passwords, or in another case simply sniff the uC’s signals. The ‘hackers’ would then later come to extract the recorded data. Consequently, we needed a secure tamper-proof Mooltipass version and an Arduino-compatible one, while allowing the former to become the latter.

Olivier’s design, though completely closed, will have several thinner surfaces directly above the Arduino headers. As a compromise, we therefore thought of sending a bootloader-free assembled version to the people only interested in the password keeper functionality, while sending a non-assembled version (with a pre-burnt bootloader) to the tinkerers. The Arduino enthusiasts would just need to cut the plastic at the strategic places (and perhaps solder headers to save costs). The main advantage of doing so is that the case would be the same for both versions. The drawback is that each board would have a different firmware depending on who it is intended for.

What do our reader think? For more detailed updates on the Mooltipass current status, you can always join the official Google group.

A 3-Axis Paper Cutting Mini Laser


Laser are awesome, and so are projects that use lasers. A recent Instructable by [kokpat] gives an overview of how to create a fully functional laser paper cutter using CDROM stepper motors and an Arduino.

What is special about this build, is that it showcases how easy it can be to build a 3-axis mechanical system used for laser cutters, CNC machines, and 3D printers. Using a stepper stage that consist of a motor screw with a nut slider based carriage, the mechanical system can be put together quite easily and cost effectively. Luckily, from an electronics and software perspective, everything is quite standardized with the proliferation of the RepRap and similar machines. Simply pick any three stepper drivers, find the most pertinent firmware, and voilà! You’re done! Well, almost. Don’t forget a 100mW violet laser!

We have seen a ton of really cool laser cutters before, but this has to be one of the cheapest. See the laser cutter in action after the break.

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Temperature Controller Gets Open Source Firmware Upgrade


Beer lovers rejoice! [Mats] has reverse engineered a temperature controller and written new open source firmware for it. This effectively gives all us homebrewers a low cost, open source software driven controller. The STC-1000 is a cheap (under $20 USD) temperature controller mass-produced in the far east. The controllers do work, but have several limitations. The programming options are somewhat limited to basic set points for heat and cool. The controller also is only programmed for temperature display in Celsius, which is a bit of an annoyance for those of us who think in Fahrenheit. Under the hood, the STC-1000 utilizes a Microchip PIC16F1828 microcontroller. Unfortunately the PIC’s protection bits were set, so the original code would have been extremely difficult to extract. Not a problem, as [Mats] reverse engineered the hardware and wrote his own firmware. A 10k NTC thermister acts as the temperature probe. The probe is read by the PIC’s ADC. These probes are not very linear, so a look up table is used to convert from volts to degrees Celsius or Fahrenheit.

[Mats] new firmware allows for up to 6 profiles. Each profile has up to 10 set points and a time duration to hold each of the set points. Hysteresis and temperature offset values are also programmable via the front panel. PIC software is often written in C using Microchip’s MPLAB tool chain, and programmed with the PICkit 3 In Circuit Serial Programming (ICSP) tool. [Mats] decided to buck the system and wrote his C code using Small Device C Compiler. To keep things simple for homebrewers who may not have Microchip tools, [Mats] used an Arduino Uno for flashing duties. Thankfully the unholy matrimony of a PIC and an AVR has not yet caused a rift in time and space. The firmware is still very much in the beta stage, so if you want to help out, join the discussion on the homebrew talk forum. If you see [Mats] tell him we owe him a Haduino which he can use to almost open his beer.

[Thanks for the tip Parker!]

Black Orb Just Wants Someone To Talk With


A team at the Royal College of Art has created Space Replay, a floating black orb that records and plays back conversations from passers-by. Space Replay is a neutrally buoyant helium balloon carrying a small payload. An Arduino, an Adafruit Wave Shield, and a small speaker make up the balloons’ brain. The team used the waverp library to record and play back sounds through their shield. 3 lithium coin cells power the system. A small vacuum formed plastic housing keeps all the internal parts together, as well as acts as a small speaker cone to amplify sounds entering and leaving the orb.

As the video shows, the final result is rather creepy. A slight breeze in a subway station caused the orb to move slowly down the hallway. One would think that space replay would freak a few people out, or at least entice the curious to touch it. Other than one amused elevator rider, the unflappable London public paid no mind to it. Maybe if it had some tea…

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A Cocktail Shaker With Android And Arduino


The most rewarding part of any project must be sitting down to see the fruits of your labors set in action for the first time and relaxing with a nice drink. [Tony DiCola] is really showing off his ability to think ahead, because his smart cocktail shaker takes care of the post-build celebration, measuring out drinks with exacting precision.

The build measures out precise amounts of any liquid with the help of a small electronic scale [Tony] picked up from Harbor Freight. Instead of trying to interface with the electronics in the scale, he instead connected a INA125 instrument amplifier to the load cell. An Arduino micro measures the weight on the load cell, and with the known densities of gin, vermouth, and Kahlua, [Tony] can get a very good idea of how much liquid is in the cocktail shaker.

The really neat part of this build is the interface: [Tony] wrote an Android app for his tablet that talks to the Arduino with an Adafruit Bluefruit Bluetooth adapter. The app receives the current weight on the load cell, displays the current amount of liquor in the cocktail shaker, and provides step-by-step instructions for making any cocktail.

It’s a handy little device to keep around the liquor cabinet, and with an absurd amount of pumps and valves could easily become the basis for a very cool cocktail bot.

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The Tannin DIY MIDI Controller


[Shantea] needed a DJ controller. While there are commercial controllers out there, none of them fit what he was looking for. He solved the problem by building the Tannin DIY MIDI controller. Tannin features 19 buttons, 16 potentiometers, and 4 LEDs. Buttons can send different MIDI messages for short presses and long presses. Pots can send 6 note on/off messages as well as MIDI control messages depending on their position. The LEDs blink in beat with the MIDI in clock. Everything is programmable and can be mapped thousands of different ways. The heart of the system is an Arduino Nano. [Shantea] used the hairless-midi library to convert MIDI to serial. The Arduino interfaces to a PC via serial over USB. On the host PC side, he ran loopbe30 to create a virtual MIDI cable to Traktor, his DJ software.

We love a build that looks just as good on the inside as on the outside, and Tannin doesn’t fail to impress in this respect. The frame is MDF, and the control panel is laser etched plastic on 3mm of Plexiglass. We really like Tannin’s flavone flair. Inside the case, wiring is kept organized and neat by zip ties and strips of wood below the button grid. [Shantea] had some noise issues connecting pots to flying wires, so he used a custom printed circuit board with a ground plane to gang the pots into 2 banks of 8. The results are something any controllerist would be proud of. Click past the break to see Tannin in action.

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A Low Cost Arduino FPGA Shield


[technolomaniac] is kicking butt over at Hackaday Projects. He’s creating a low cost Arduino based FPGA shield. We’ve seen this pairing before, but never with a bill of materials in the $25 to $30 range. [technolomaniac's] FPGA of choice is a Xilinx Spartan 6. He’s also including SDRAM, as well as an SPI Flash for configuration. Even though the Spartan 6 LX9 is a relatively small FPGA, it can pack enough punch that the Arduino almost becomes a peripheral. The main interconnect between the two will be the Arduino’s ability to program the Spartan via SPI. Thanks to the shared I/O pins though, the sky is the limit for parallel workflow.

[technolomaniac] spent quite a bit of time on his decoupling schematic. Even on a relatively small FPGA power decoupling is a big issue, especially when high speed signals come into play. Thankfully Xilinx provides guides for this task. We have to mention the two excellent videos [technolomaniac] created to explain his design. Documenting a project doesn’t have to be hours of endless writing. Sometimes it’s just easier to run a screen capture utility and click record. As of this writing, the schematic has just been overhauled, and [technolomaniac] is looking for feedback before he enters the all important layout stage. The design is up on his github repository in Altium format. Due to its high cost, Altium isn’t our first pick for Open Hardware designs. There are free viewers available, but [technolomaniac] makes it simple by putting up his schematic in PDF format (PDF link). Why not head over to projects and help him out?

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