Tag Archives: hardware

A LIN Bus Signal Injector

via Hackaday» hardware

LIN bus signal injector

[Zapta] tipped us about his latest project: a LIN bus signal injector. For our unfamiliar readers, the LIN bus is a popular automotive bus that is used to interface with buttons, lights, etc. As [Zapta] was tired of having to press the Sport Mode button of his car each time he turned the ignition on, he thought it’d build the platform shown above to automatically simulate the button press.

The project is based around an ATMega328 and is therefore Arduino IDE compatible (recognized as an Arduino Mini Pro), making firmware customization easy. In the car, it is physically setup as a proxy between the LIN master and the slave (which explains the two 3-wires groups shown in the picture). It is interesting to note that the injection feature can be toggled by using a particular car buttons press sequence. The project is fully open source and a video of the system in action is embedded after the break.


Filed under: Arduino Hacks, hardware

Measuring Frequency Response with an RTL-SDR Dongle and a Diode

via Hackaday» hardware

[Hans] wanted to see the frequency response of a bandpass filter but didn’t have a lot of test equipment. Using an RTL-SDR dongle, some software and a quickly made noise generator, he still managed to get a rough idea of the filter’s characteristics.

How did he do it? He ‘simply’ measured his noise generator frequency characteristics with and without the bandpass filter connected to its output and then subtracted one curve with the other. As you can see in the diagram above, the noise generator is based around a zener diode operating at the reverse breakdown voltage. DC blocking is then done with a simple capacitor.

Given that a standard RTL-SDR dongle can only sample a 2-3MHz wide spectrum gap at a time, [Hans] used rtlsdr-scanner to sweep his region of interest. In his write-up, he also did a great job at describing the limitations of such an approach: for example, the dynamic range of the ADC is only 48dB.


Filed under: hardware, wireless hacks

Building a Mesh Networked Conference Badge

via Hackaday» hardware

[Andrew] just finished his write-up describing electronic conference badges that he built for a free South African security conference (part1, part2). The end platform shown above is based on an ATMega328, a Nokia 5110 LCD, a 433MHz AM/OOK TX/RX module, a few LEDs and buttons.

The badges form a mesh network to send messages. This allows conversations between different attendees to be tracked. Final cost was the main constraint during this adventure, which is why these particular components were chosen and bought from eBay & Alibaba.

The first PCB prototypes were CNC milled. Once the PCB milling was complete there was a whole lot of soldering to be done. Luckily enough [Andrew]‘s friends joined in to solder the 77 final boards. He also did a great job at documenting the protocol he setup, which was verified using the open source tool Maltego. Click past the break to see two videos of the system in action.


Filed under: hardware, wireless hacks

Developed on Hackaday: Olivier’s Design Rundown

via Hackaday» hardware

The Hackaday writers and readers are currently working hand-in-hand on an offline password keeper, the Mooltipass. A few days ago we presented Olivier’s design front PCB without even showing the rest of his creation (which was quite rude of us…). We also asked our readers for input on how we should design the front panel. In this new article we will therefore show you how the different pieces fit together in this very first (non-final) prototype… follow us after the break!

This is the bottom PCB, containing the main micro-controller, the Arduino headers and the FPC connector for the OLED screen. Finding low profile standard .1″ female connectors was one of our longest Google searches. The ones you can see above are pass-through connectors, which means that the pins can go through the PCB.

This is the CNC-milled prototype case. On the bottom you may notice two slots having a smaller depth to the other end, positioned right on top of the Arduino connectors. As previously mentioned in our Developed on Hackaday articles, we want to give the final users the ability to convert their secure password keeper into an Arduino platform. As you may have guessed, converting the Mooltipass will be as simple as cutting this thin plastic layer (see top of the picture) to access the Arduino headers and unlock the platform.

This is how the bottom PCB fits into the case. 4 screws can be used to keep everything in place. The large elevated plastic area serves as a flat surface for the smartcard:

The OLED screen then rests on the case’s sides:

Enough space is left behind the screen for the flex PCB to comfortably bend. Finally, the top board fits in the remaining space and the acrylic panel is put on top of the assembly:

As our last article stated, we obviously still have some things to perfect. In the meantime, we are going to hand solder a few prototypes and ship them out to our current developers.

Want to stay informed? You can join the official Mooltipass Google Group or follow us on Hackaday Projects.


Filed under: Featured, hardware

Developed on Hackaday: The Top PCB dilemna

via Hackaday» hardware

The Hackaday community offline password keeper is slowly coming together. A few days ago we received the top PCB for Olivier’s design (shown above). If you look at the picture below, you may see the problem we discovered when opening our package: the soldermask was the wrong color! Given the board is meant to be placed behind a tinted acrylic panel, this was quite a problem…

After using some spray paint, we managed to get to the point shown in the bottom left of the picture. The next task was to find the best way to illuminate the input interface with reverse mount LEDs. Using a CNC mill we machined openings (top right PCB) but also removed some epoxy on both PCB’s sides, thinking it would provide a better light diffusion. We then wrote part of the Mooltipass PWM code and took these pictures:

Using the FR4 to diffuse the light

Cut through openings

We hope you agree that the ‘FR4 version’ looks better. The other version, which has the cut openings, illuminates unevenly because the smartcard isn’t under all of the LEDs. This raises several questions that we hope our dear Hackaday readers can answer:

  1. Can this kind of machining be done in standard PCB fabs?
  2. Instead of leaving the bare FR4 on top, should we cover it with white soldermask?
  3. Instead of leaving the bare FR4 on top, should we cover it with white silkscreen?

Keep in mind that we would only need to machine one PCB’s side.

Another concern is the top panel. As previously mentioned we’re currently using a tinted acrylic panel, which may not be the best solution to prevent scratches. We’re thinking to use glass in the future (corning gorilla glass?) so we may also hide everything around the display’s active area. Do you guys have any experience with this? Would it be expensive in relatively small quantities?

As you can see, we still need to find the best compromises and we hope you can help us. Please post a quick message in the comment section below or contact the team in the official Mooltipass Google Group.

 


Filed under: Hackaday Columns, hardware

DIY Linear Actuators For A Flight Sim

via Hack a Day» hardware

linear

[Roland] has already built a few very cool and extremely realistic flight sims, but his latest project will put his current rig to shame. He’s building a six degree of freedom simulator based on homebuilt linear actuators of his own design.

The actuator is powered by a large DC motor moving timing belts along the length of the enclosure. These timing belts are connected to a shaft that’s coupled to the frame with a few bungee cords. The bungee cords are important; without them, the timing belts would be carrying all the load of the sim – not a good thing if these actuators are moving an entire cockpit around a living room.

Also on [Roland]‘s list of awesome stuff he’s building for his flight sims is a vibration system based on the BFF Shaker. This board takes data in from sim software and turns it into vibrations produced by either unbalanced DC motors or one of those ‘bass kicker’ transducers.

It’s all very cool stuff, and with all the crazy upgrades [Roland] is doing to his sim rig, he’s doing much better than paying $300/hour to rent a Beechcraft Baron.

 


Filed under: hardware, robots hacks

ISPnub – A Stand-Alone AVR In-System-Programmer Module

via Hack a Day» hardware

[Thomas] tipped us about his latest project: a stand-alone AVR programmer module named ISPnub. As you can see in the picture above, it is a simple circuit board composed of a main microcontroller (ATmega1284p), one button and two LEDs. Programming a target is a simple as connecting the ISPnub and pressing the button. The flashing operation success status is then shown using the green/red LED.

ISPnub gets its power from the target circuit so no external power supply is needed. It works over a wide voltage range: 1.8V to 5.5V. The module also features a programming counter which can be used to limit the number of programming cycles. A multi-platform Java tool is in charge of embedding the target flash contents with the ISPnub main firmware. The complete project is open source so you may want to check out the official GitHub repository for the firmware and the project’s page for the schematics.


Filed under: hardware

Developed on Hackaday: 2 Days Left to Submit your Design!

via Hack a Day» hardware

We’re sure that many of Hackaday readers already know that one of the two main components of the Mooltipass project is a smart card, containing (among others) the AES-256 encryption key. Two weeks ago we asked if you’d be interested coming up with a design that will be printed on the final card. As usual, many people were eager to contribute and recently sent us a few suggestions. If you missed the call and would like to join in, it’s not too late! You may still send your CMYK vector image at mathieu[at]hackaday[dot]com by sunday. More detailed specifications may be found here.

In a few days we’ll also publish on Hackaday a project update, as we recently received the top and bottom PCBs for Olivier’s design. The low level libraries will soon be finished and hopefully a few days later we’ll be able to ship a few devices to developers and beta testers. We’re also still looking for contributors that may be interested in helping us to develop browser plugins.

The Mooltipass team would also like to thank our dear readers that gave us a skull on Hackaday projects!


Filed under: Hackaday Columns, hardware

Fake Audiophile Opamps Revealed

via Hack a Day» hardware

chip

The OPA627 is an old, popular, and very high-end opamp found in gear cherished by the most discerning audiophiles. This chip usually sells for at least $15, but when [Zeptobars] found a few of these expensive chips on ebay going for $2, his curiosity was piqued. Something just isn’t right here.

[Zeptobars] is well known for his decapsulating and high-resolution photography skills, so he cut the can off a real OPA627, and dissolved one of the improbably cheap ebay chips to reveal the die. Under the microscope, he found an amazing piece of engineering in the real chip – laser trimmed resistors, and even a nice bit of die art.

The ebay chip, if it were real, would look the same. It did not. The ebay chip only contained one laser trimmed resistor and looks to be a much simpler circuit. After a bit of research, [Zeptobars] found it was actually an AD774 opamp. The difference is small, but the AD774 still has much higher noise – something audiophiles could easily differentiate with their $300 oxygen-free volume knobs.

This isn’t the first instance of component counterfeiting [Zeptobars] has come across. He’s found fake FTDI chips before, and we’re counting the days until he gets around to putting a few obviously fake ebay 6581 SID chips under the microscope.


Filed under: hardware

Using SIMMs to Add Some Extra RAM on your Arduino UNO

via Hack a Day» hardware

 

A Single In-line Memory Module (SIMM) is a type of memory module containing Random Access Memory (RAM) which was used in computers from the early 1980s to the late 1990s (think 386, 486, Macintoshs, Atari STE…). [Rafael] just made a little library that allows you to interface these modules to the Atmega328p-based Arduino UNO in order to gain some memory space. His work was actually based on the great Linux on the 8bit ATMEGA168 hack from [Dmitry Grinberg] but some tweaks were required to make it work with [Rapfael]‘s SIMM but also to port it to the Arduino platform. The 30-pin SIMM shown above is capable of storing up to (hold on to your chairs…) 16MB but due to limited amount of available IOs on the Atmega328p only 256KB can be used. Our guess it that an SPI / I2C IO extender could lift this limitation. A quick (shaky) video is embedded after the break.


Filed under: Arduino Hacks, hardware

Dirt Cheap Dirty Boards Offers Dirt Cheap PCB Fab

via Hack a Day» hardware

Dirt Cheap PCB

 

When your project is ready to build, it’s time to find a PCB manufacturer. There are tons of them out there, but for prototype purposes cheaper is usually better. [Ian] at Dangerous Prototypes has just announced Dirt Cheap Dirty Boards, a PCB fabrication service for times where quality doesn’t matter too much. [Ian] also discussed the service on the Dangerous Prototypes forum.

The boards are definitely cheap. $12 USD gets you ten 5 cm by 5 cm boards with 100% e-test and free worldwide shipping. You can even choose from a number of solder mask colors for no additional cost. [Ian] does warn the boards aren’t of the best quality, as you can tell in the Bus Pirate picture above. The silkscreen alignment has some issues, but for $1.2 a board, it’s hard to complain. After all, the site’s motto is “No bull, just crappy PCBs.”

The main downside of this service will be shipping time. While the Chinese fab house cranks out boards in two to four days, Hong Kong Post can take up to 30 days to deliver your boards. This isn’t ideal, but the price is right.


Filed under: hardware

Raspberry Pi Compute Module: new product!

via Raspberry Pi

As regular readers will know, it’s been a busy time here at Pi Towers recently with the launch of our new website, free educational materials and £1m education fund.

On the engineering side of things we’ve also been very busy over the past year, and not to be outdone by the education team, we are ready to take the wraps off something special, this time aimed at business and industrial users.

What's this little thing? Read on to find out.

What’s this little thing? Read on to find out.

From humble beginnings, the Raspberry Pi platform has grown and matured: the software is now full-featured and stable, and is still constantly improving thanks to the continuing hard work of our heroic community of volunteers; as well as targeted injections of funding to solve some specific issues. The Pi, and the Broadcom BCM2835 SoC at its heart, are also steadily becoming more open.

We love hearing about what users are doing with their Raspberry Pis, and are constantly amazed at the range of projects, as well as the inventiveness and creativeness of the community. We are also aware that there are a very significant number of users out there who are embedding the Raspberry Pi into systems and even commercial products. We think there needs to be a better way to allow people to get their hands on this great technology in a more flexible form factor, but still keep things at a sensible price.

Like proud parents, we want to free the core technology of the Raspberry Pi to go forth and become an integral part of new and exciting products and devices, and so today we are announcing the forthcoming Raspberry Pi Compute Module.

CM_and_pi-small

Compute Module on the left. What does it do? Read on to find out.

The compute module contains the guts of a Raspberry Pi (the BCM2835 processor and 512Mbyte of RAM) as well as a 4Gbyte eMMC Flash device (which is the equivalent of the SD card in the Pi). This is all integrated on to a small 67.6x30mm board which fits into a standard DDR2 SODIMM connector (the same type of connector as used for laptop memory*). The Flash memory is connected directly to the processor on the board, but the remaining processor interfaces are available to the user via the connector pins. You get the full flexibility of the BCM2835 SoC (which means that many more GPIOs and interfaces are available as compared to the Raspberry Pi), and designing the module into a custom system should be relatively straightforward as we’ve put all the tricky bits onto the module itself.

So what you are seeing here is a Raspberry Pi shrunk down to fit on a SODIMM with onboard memory, whose connectors you can customise for your own needs.

The Compute Module is primarily designed for those who are going to create their own PCB. However, we are also launching something called the Compute Module IO Board to help designers get started.

Empty IO board on the left: Compute Module snapped into place on the right.

Empty IO Board on the left: Compute Module snapped into place on the right.

The Compute Module IO Board is a simple, open-source breakout board that you can plug a Compute Module into. It provides the necessary power to the module, and gives you the ability to program the module’s Flash memory, access the processor interfaces in a slightly more friendly fashion (pin headers and flexi connectors, much like the Pi) and provides the necessary HDMI and USB connectors so that you have an entire system that can boot Raspbian (or the OS of your choice). This board provides both a starting template for those who want to design with the Compute Module, and a quick way to start experimenting with the hardware and building and testing a system before going to the expense of fabricating a custom board.

IO Board

IO Board

Initially, the Compute Module and IO Board will be available to buy together as the Raspberry Pi Compute Module Development Kit.

These kits will be available from RS and element14 some time in June. Shortly after that the Compute Module will be available to buy separately, with a unit cost of around $30 in batches of 100; you will also be able to buy them individually, but the price will be slightly higher. The Raspberry Pi Foundation is a charity, and as with everything we make here, all profits are pushed straight back into educating kids in computing.

I’m sure people will be keen to get their design process started; initially we are releasing just the schematics for both the Compute Module and IO Board, but we will be adding plenty more documentation over the coming days and weeks.

Happy creating!

*But don’t go plugging the Compute Module into your laptop – the pins assignments aren’t even remotely the same!

CPLD Tutorial: Learn Programmable Logic the Easy Way

via Hack a Day» hardware

739px-Altera_MAX_7128_2500_gate_CPLD

The guys over at hackshed have been busy. [Carl] is making programmable logic design easy with an 8 part CPLD tutorial. Programmable logic devices are one of the most versatile hardware building blocks available to hackers. They also can have a steep learning curve. Cheap Field Programmable Gate Arrays (FPGA) are plentiful, but can have intricate power requirements. Most modern programmable logic designs are created in a Hardware Description Language (HDL) such as VHDL or Verilog. Now you’ve got a new type of device, a new language, an entirely new programming paradigm, and a complex IDE to learn all at once. It’s no wonder FPGAs have sent more than one beginner running for the hills.

The tutorial cuts the learning curve down in several ways. [Carl] is using Complex Programmable Logic Devices (CPLD). At the 40,000 foot level, CPLDs and FPGAs do the same thing – they act as re-configurable logic. FPGAs generally do not store their configuration – it has to be loaded from an external FLASH, EEPROM, or connected processor. CPLDs do store their configuration, so they’re ready as soon as they power up. As a general rule, FPGAs contain more configurable logic than CPLDs. This allows for larger designs to be instantiated with FPGAs. Don’t knock CPLDs though. CPLDs have plenty of room for big designs, like generating VGA signals.

[Carl] also is designing with schematic capture in his tutorial. With the schematic capture method, digital logic schematics are drawn just as they would be in Eagle or KiCad. This is generally considered an “old school” method of design capture. A few lines of VHDL or Verilog code can replace some rather complex schematics. [Carl's] simple designs don’t need that sort of power though. Going the schematic capture route eliminates the need to learn VHDL or Verilog.

[Carl's] tutorial starts with installing Altera’s Quartus II software. He then takes the student through the “hardware hello world” – blinking an LED.  By the time the tutorial is done, the user will learn how to create a 4 bit adder and a 4 bit subtractor. With all that under your belt, you’re ready to jump into big designs – like building a retrocomputer.

[Image via Wikimedia Commons]


Filed under: FPGA, hardware

Open Source Power Line Communication

via Hack a Day» hardware

Power Line Communication Filtering

 

Since we all have wires running throughout our houses to provide mains power, there’s a number of devices that piggyback on mains lines for communication. For his thesis project, [Haris Andrianakis] developed his own power line communication system.

The basic principle of the system is to inject a signal onto the power lines at a much higher frequency than the 50 or 60 Hz of the AC power itself. Using both active and passive filters, the signal can be separated from the AC power and decoded. This system uses frequency-shift keying to encode data. This part is done by a ST7540 modem that’s designed for power line applications. The modem is controlled over SPI by an ATmega168 microcontroller.

[Haris]‘ write up goes into detail about some of the challenges he faced, and how to protect the device from the high voltages present. The final result is a remote display for a weigh scale, which communicates over the power line. Schematics, PCB layout, and software are all available.


Filed under: hardware, home hacks

Building an Inductive Loop Vehicle Detector

via Hack a Day» hardware

[Trax] was asked by a friend to build a device that could detect the presence of a car in front of his garage gate for it to open automatically. After searching the web for such a project and trying many of them, he decided to build his own detector based on an induction loop. As you may have guessed, this kind of detector works by detecting an inductance change in a wire loop (aka coil) buried in the road. Having a car pass several inches on top of it produces such an effect.

[Trax]‘s write-up shows a very well thought and professional design. All the detector parameters can be adjusted using DIP switches and buttons: detection type (presence/pulse), signal filtering, main frequency and sensitivity. The wire loop is isolated from the main sensor electronics using a 1:1 isolation transformer and a Colpitts oscillator is used to drive the latter. Moreover, gas discharge tubes are also used for lightning protection.

The change in inductance translates to a change in resonant frequency which is later detected by the main microcontroller. The board is 24V AC powered and a diode bridge + LM2596 SMPS step-down converter are in charge of generating the required +5V in an efficient way.

As if this was not enough, [Trax] also made a PC-based tool that can change other platform settings using a serial connection. All the resources can be downloaded from his website and a few videos are embedded after the break.


Filed under: hardware, transportation hacks