OpenDrop V2 is an updated design for an open-source digital microfludics platform, which was initiated by GaudiLabs in Luzern, Switzerland and developed by several communities including hackteria | open source biological art, BioFlux and digi.bio. The device is part of a much larger ecosystem focused around digital biology with hopes of making personal lab automation accessible to more people.
OpenDrop runs on a new technology called “electro-wetting” to control small droplets of liquids, which allows anyone to carry out digital biology experiments. Potential applications are not only limited to science, but the art, music, gaming and education fields as well.
One such example is OpenDropper, an 8-bit video game based on the OpenDrop. You can see it below!
Finding a product that is everything you want isn’t always possible. Making your own that checks off all those boxes can be. [Peter Clough] took the latter route and built a small Bluetooth speaker with an LED visualization display that he calls Magic Box.
A beefy 20W, 4Ohm speaker was screwed to the lid of a wooden box converted to the purpose. [Clough] cut a clear plastic sheet to the dimensions of the box, notching it 2cm from the edge to glue what would become the sound reactive neopixel strip into place — made possible by an electret microphone amplifier. There ended up being plenty of room inside the speaker box to cram an Arduino Pro Mini 3.3V, the RN-52 Bluetooth receiver, and the rest of the components, with an aux cable running out the base of the speaker. As a neat touch, neodymium magnets hold the lid closed.
We gotta say, a custom speaker with LED visualization makes for a tidy little package — aside from the satisfaction that comes from building it yourself.
High-altitude ballooning is becoming a popular activity for many universities, schools and hacker spaces. The balloons, which can climb up to 40 km in the stratosphere, usually have recovery parachutes to help get the payload, with its precious data, back to solid ground safely. But when you live in areas where the balloon is likely to be flying over the sea most of the time, recovery of the payload becomes tricky business. [Paul Clark] and his team from Durham University’s Centre for Advanced Instrumentation are working on building a small, autonomous glider – essentially a flying hard drive – to navigate from 30 km up in the stratosphere to a drop zone somewhere near a major road. An important element of such a system is the locator beacon to help find it. They have now shared their design for an “Iridium 9603 Beacon” — a small Arduino-compatible unit which can transmit its location and other data from anywhere via the Iridium satellite network.
The beacon uses the Short Burst Data service which sends email to a designated mail box with its date, time, location, altitude, speed, heading, temperature, pressure and battery voltage. To do all of this, it incorporates a SAMD21G18 M0 processor; FGPMMOPA6H GPS module; MPL3115A2 altitude sensor; Iridium 9603 Short Burst Data module + antenna and an LTC3225 supercapacitor charger. Including the batteries and antenna, the whole thing weighs in at 72.6 g, making it perfectly suited for high altitude ballooning. The whole package is powered by three ‘AAA’ Energizer Ultimate Lithium batteries which ought to be able to withstand the -56° C encountered during the flight. The supercapacitors are required to provide the high current needed when the beacon transmits data.
The team have tested individual components up to 35 km on a balloon flight from NASA’s Columbia Scientific Balloon Facility and the first production unit will be flown on a much smaller balloon, launched from the UK around Christmas. The GitHub repository contains detailed information about the project along with the EagleCAD hardware files and the Arduino code. Now, if only Santa carried this on his Sleigh, it would be easy for NORAD to track his progress in real time.
Say hello to the newest member of the Arduino family! The MKRZero–now available on our stores at the price of $21.90/€20.90 (+ tax)–shrinks the functionality of the Arduino Zero down into an Arduino MKR1000 form factor, making it a great educational tool for learning about 32-bit application development.
Like the Zero, the latest board is based on a Microchip SAM D21 ARM Cortex®-M0+ MCU. An integrated SD connector with dedicated SPI interfaces (SPI1) allows you to play with files without any extra hardware, while an analog converter enables you to monitor its battery voltage.
The MKRZero’s features in a nutshell:
small form factor
number crunching capability
low power consumption
integrated battery management
USB host
integrated SD management
programmable SPI, I2C and UART
Interested? You can explore the MKRZero in more detail, including its technical documentation, via the links below:
If you use the Arduino IDE, you will need to add the new Intel SAMD Core, selecting Tools menu, then Boards, and last Boards Manager on the Arduino Software (IDE).
Watch out music makers, we’ve got some news for you! We have released two libraries for your enjoyment:
Arduino Sound library – a simple way to play and analyze audio data using Arduino on SAM D21-based boards.
I2S library – to use the I2S protocol on SAMD21-based boards. For those who don’t know, I2S (Inter-IC Sound) is an electrical serial bus interface standard for connecting digital audio devices.
This robust DIN-rail mountable, Leonardo-compatible controller enables you to take your existing Arduino projects and swiftly transform them into permanent installations. The prototyping area and screw connectors allow you to install your own circuitry and reliably connect to accessories.
In the video below, Industruino co-founder Loic De Buck discusses these key features and more with Davide Gomba. (You can also find an extended version here.)
The team recently created an excellent tutorial showing how you to build an Arduino-based electricity consumption monitor with the Industruino PROTO platform. You can use it to measure AC power of your appliances, including a water cooker, TV, laptop charger, or anything else plugged into a wall socket. Alternatively, you can even use it in your electricity cabinet to evaluate the power consumption throughout your entire house (at least one phase).
The challenge is to measure an AC of a relatively high voltage (220-240V) with a direct current 5V Arduino MCU.
This may seem dangerous, but we will use a non-invasive Current Transformer (CT), so our Arduino remains galvanically isolated from the high voltage AC.
This prototype is based on the excellent open source project OpenEnergyMonitor. It uses parts of the its standard emonTx hardware and software to report the AC apparent power consumption, based on measurements of a Current Transformer as in the picture on the left. The original project also allows to measure 3 phase and/or real power, but for our prototype here we are only measuring the current of one phase, not its voltage which would require an AC/AC adaptor.
“The great thing about standards is that there are so many to choose from.” Truer words were never spoken, and this goes double for the hobbyist world of hardware hacking. It seems that every module, every company, and every individual hacker has a favorite way of putting the same pins in a row.
We have an entire drawer full of adapters that just go from one pinout to another, or one programmer to many different target boards. We’ll be the first to admit that it’s often our own darn fault — we decided to swap the reset and ground lines because it was convenient for one design, and now we have two adapters. But imagine a world where there was only a handful of distinct pinouts — that drawer would be only half full and many projects would simply snap together. “You may say I’m a dreamer…”
This article is about connectors and standards. We’ll try not to whine and complain, although we will editorialize. We’re going to work through some of the design tradeoffs and requirements, and maybe you’ll even find that there’s already a standard pinout that’s “close enough” for your next project. And if you’ve got a frequently used pinout or use case that we’ve missed, we encourage you to share the connector pinouts in the comments, along with its pros and cons. Let’s see if we can’t make sense of this mess.
FTDI TTL Serial
The de-facto standard for a hacker’s TTL serial pinout is definitely the layout that FTDI uses for their USB/TTL serial cables. Said cable is just so handy to have on hand that you’d be silly to use any other pinout for the job. And the good news is that the rest of the world has basically joined in. From the Chinese “Pro Mini” cloneduinos to the Hackaday Edition Huzzah ESP8266 board, and from Adafruit’s FTDI Friend to Modern Device’s USB-BUB, almost everyone uses this pinout. A victory for the common man!
There is one slight point of contention, however, and that’s whether pin 6 is DTR or RTS#. We never use either, so we couldn’t care less, but if you’re counting on your programmer sending the DTR signal to enter programming mode on the device (we’re looking at you Arduino!) then you’ll want DTR on pin 6, and the original FTDI cable, ironically, has the “wrong” pinout. Perhaps that’s why Sparkfun avoided the whole debacle and went their own way, breaking out every signal off the FTDI chip into their own unique configuration.
If you’re only going to break out TTL serial lines, you’d be a fool to use any other pinout.
Modules and Other Communications
Unlike the case with simple serial, connecting various kinds of modules to mainboards is a difficult problem. Creating a single pinout or connector specification for many potential protocols or arbitrary signals is a Herculean task. Surprisingly, it’s been done a few times over. Here are some notables.
Pmod
Digilent makes a wide range of FPGA demo boards, and they needed an in-house standard pinout that they could use to plug into various add-on peripheral modules that they sell. Thus Pmod was born. It has since become a full-fledged, and trademarked, open standard that you can use in your designs. Here’s the PDF version of the specification for you to print out, so you know they mean business.
There are a few aspects of Pmod that we think are particularly clever. First, the number of pins involved is “just right” at six, and it’s easily expandable. They use standard 0.1″ pitch pins and headers. Two lines carry power and ground, leaving four free pins for SPI, UART, or whatever else. The specification is that all power and signal voltages are 3.3 V because they’re designed for FPGAs after all. You can mix and match if you know what you’re doing, but they won’t let you call it Pmod(tm).
Eric Brombaugh’s iceRadio FPGA SDR, plugged together with Pmods
If you need more than four signals, there’s a twelve-pin version which is just two six-pin Pmods stacked into a double-row header. The extra power and ground are redundant, but it makes a twelve-pin output very flexible, because nothing stops it from being used as two sixes. The standard also says that the twelve-pin headers are to be spaced at 0.9″ center-to-center, so you can even connect two of them together when you need sixteen board-to-board signal connections. We like the modularity and expandability.
Pmod connectors are multi-protocol, but for each protocol there is a single pinout. So there’s an SPI Pmod and an I2C Pmod, and the pins are always in the same place. There isn’t a Pmod standard for every conceivable application, of course, so there’s a GPIO pinout that gives you free rein over what goes where. We think that it would be nice if some additional notable protocols (I2S? one-wire? servos? analog stereo audio?) were included in the specs, but the community can also handle these lower-level details.
In our eyes, Pmod is nearly perfect. It uses cheap hardware, is easily expandable, and the smallest incarnations are small enough to fit on all four sides of a one-inch-square board. If you’re willing to pay the brand-name premium, Digilent makes an incredible range of modules. We want to see more hackers outside of the FPGA scene get on it.
mikroBUS
What Digilent is to development boards in the US, MikroElektronika is in Europe. While Pmod aims to be capable of doing anything, Mikro-E’s mikroBUS connector wants to do everything, which is to say it has I2C, SPI, UART, two voltages, and even a few extra signals all on the same pinout. Physically, it’s two single rows of eight pins, spaced 0.9″ apart side-to-side, which means it fits into a breadboard nicely. Here’s the spec in PDF.
The tradeoff here, relative to Pmod, is that a lot of pins go unused on any given design. With (only) one “analog” channel, you wouldn’t choose mikroBUS to send stereo audio, whereas nothing stops you from calling the Pmod’s GPIO lines analog and sending four channels of sound. But that mikroBUS gains is fool-proofness. (Well, they could have also made it asymmetric…) There’s no chance of a newbie plugging an SPI module in where an I2C module is expected and scratching their heads. With mikroBus, it should just work.
Microchip has added a mikroBus port to their Curiosity boards, and MikroElektronika makes a ton of modules. If your audience consists of beginners, and one footprint for all protocols, it’s worth considering.
Seeed’s Grove
Meanwhile in China, Seeed Studios makes open-source modules, and makes them cheap. Their Grove connector uses only four pins, with power and ground among them. The have standard pinouts for UART, I2C, and for servo motors. Sensors and other analog peripherals are allocated one “primary” pin and one “secondary” and it’s assumed that you know what you’re doing. The idea behind their system is that you add a shield to your microcontroller board, and they break out the relevant pins into these four-pin Grove headers.
This is great for small things and I2C devices, which is Seeed’s catalog, but there just aren’t enough signal pins to run SPI or an analog RGB LED, for instance. But because of the small number of pins, they use very inexpensive polarized cables and shrouds that you can’t plug in the wrong way, and that take up relatively little board space. That’s Grove’s design trade-off.
Servo Motor control
One of these things is not like the others…
Hobby servo motors need three wires: voltage, ground, and a signal to tell them where to point. There are three distinct ways to arrange these wires, but Futaba, HiTec, Tower, GWS, and JR servos all chose to put them in SVG (or GVS) order, and there’s no reason to buck the trend. (Airtronics, what were you thinking?!)
SVG is also a handy pinout to use for all sorts of one-signal sensors or actuators where space is a premium, and we’ve seen this in a few designs (here and here, for instance). But we’re torn. Relative to the Grove, for instance, you’re just saving one pin. Even the Pmod would work with only three pins’ overhead. Is that worth complicating your life with another pinout? If you need a lot of powered one-signal devices, or servos, it probably is, and you can hardly beat SVG or GVS, whichever way you look at it.
Arduino
Viewed in the light of any of the other module interconnection systems, the Arduino is the worst of all worlds. It’s monolithic like mikroBUS, but it’s gigantic — you have to build a 55×73 mm board and accommodate 30 pins and pass-throughs if you’d like it to be stackable. The pins have a funny spacing (that gap!), that doesn’t fit any normal protoboard. Nobody goes through the trouble of building a shield just for an I2C connection. No wonder most Arduino projects look like a breadboard hedgehog. About the only good thing we can say about it is that it’s hard to plug one in backwards.
There’s also the tiny little factor that there’s a million Arduino shields out there, a huge community built around them, and widespread support for them. Which turns out to trump all of the reasonable design concerns. (Shakes head.)
Miscellany
Of course, there are other very specific pinouts that one might encounter, like the old ESP-01 module, or the XBee, or the nRF24. Adapting modules to fit boards is always going to be a pain, because the manufacturers will pick whatever suits them on that day. Programmer pinouts for specific microcontrollers are a similar story, as is JTAG, which is a beautiful standard with a dogs’ breakfast of pinout possibilities. (We could do a whole column!)
Faced with this inevitability, and the need for many one-off adapters, what can you do? What we do is buy a lot of those cheap “Dupont” female-to-female cables, get the connections working and tested, and then tape them permanently together and label them. It’s not as pretty as a dedicated PCB adapter, but it’s quick and easy and gets you moving on to what you wanted to do in the first place.
Wrapup and Recommendations
The goal of connectors, and their standards, is putting parts together. If you’re designing a sensor module with more than a couple components, and you want it to be maximally easy for yourself and others to hook up to whatever mainboard they’ve got, this is no easy task. The end result is a proliferation of translators, adapter boards, hats, shields, capes, or whatever else. We have a drawer and a half full, and we bet you do too.
Yes, I do see what I’m suggesting here. [source: xkcd 927]We’d be happy to see the world settle on Pmod for most needs, honestly, and we’d even throw away our beloved FTDI serial pinout in the name of standardization (or make an adapter). We can also see the need for exceptions like SVG / servo connectors when small sensors or multiples are in play. There will always be the need for dedicated on-board connectors as well, of course. Nobody said hardware was easy.
What’s your solution to the ultimate connector conundrum? Are there important connector systems that we’ve left out? What are their design tradeoffs? How stoked would you be if things could just plug together? Let us know!
As we’ve mentioned previously, the integrity of your vehicle in an era where even your car can have a data connection could be a dubious bet at best. Speaking to these concerns, a soon-to-be published paper out of the University of Birmingham in the UK, states that virtually every Volkswagen sold since 1995 can be hacked and unlocked by cloning the vehicle’s keyfob via an Arduino and software defined radio (SDR).
The research team, led by [Flavio Garcia], have described two main vulnerabilities: the first requires combining a cyrptographic key from the vehicle with the signal from the owner’s fob to grant access, while the second takes advantage of the virtually ancient HiTag2 security system that was implemented in the 1990s. The former affects up to 100 million vehicles across the Volkswagen line, while the latter will work on models from Citroen, Peugeot, Opel, Nissan, Alfa Romero, Fiat, Mitsubishi and Ford.
The process isn’t exactly as simple as putting together $40 of electronics and walking away with a vehicle. The would-be thief must be close in order to detect the fob’s unique key — although they only need to do so once for that vehicle! — as well as reverse-engineer the other half of the code from the vehicle’s internal network. Exploiting HiTag2’s vulnerabilities to unlock the vehicle can be achieved within a minute by a well-prepared thief. [Garcia] and his team note that only the VW Golf 7 has been spared from this exploit.
If thievery is not your thing and you’re looking to white-hat hack your vehicle, Volkswagen still has the best option in the form of the loveable Beetle.
Enigma machines are fascinating devices, especially for young Makers looking to explore the world of electronics. Awhile back we featured a similar project from Italy, and we’re once again amazed by the work of 14-year-old Andy Eggebraaten, who built a retro-modern gadget of his own. The project, which was for his high school’s science fair, took nine months to complete.
These electro-mechanical rotor cipher machines were developed in the early 20th century to protect commercial, diplomatic and military communication, used especially by German military intelligence during World War II.
In the video below, Andy opens the machine to show its inner workings: the unit runs on Arduino Mega along with 1,800 other parts and 500 color-coded wires. We can see that he evolved the rotors into electronic modules that plug into D-Sub sockets, and the interface is made using a 16-segment display showing the rotor position as well as an LCD screen to read the plain- and the encoded text.
It is likely that many of us will at some time have experimented with motion detectors. Our Arduinos, Raspberry Pis, Beaglebones or whatever will have been hooked up to ultrasonic or PIR boards which will have been queried for their view of what is in front of them.
[Connornishijima] has stumbled on a different way to detect motion with an Arduino, he’s polling an ADC pin with a simple length of twisted pair hooked up to it and earth, and reliably generating readings indicating when he (or his cat) is in its vicinity. He’s calling the effect “Capacitive turbulence”, and he’s open to suggestions as to its mechanism. He can only make it work on the Arduino, other boards with ADCs don’t cut it.
Frequent Hackaday featuree [Mitxela] may have also discovered something similar, and we’ve hesitated to write about it because we didn’t understand it, but now it’s becoming unavoidable.
It’s always dangerous in these situations to confidently state your opinion as “It must be…” without experimental investigation of your own. Those of us who initially scoffed at the idea of the Raspberry Pi 2 being light sensitive and later had to eat their words have particular cause to remember this. But this is an interesting effect that bears understanding. We would guess that the Arduino’s fairly high input impedance might make it sensitive to mains hum, if you did the same thing to an audio amplifier with a phono input you might well hear significant hum in the speaker as your hand approached the wire. It would be interesting to try the experiment at an off-grid cabin in the woods, in the absence of mains hum.
If you’d like to give his experiment a try, he’s posted his sketch on Pastebin. And he’s put up the video below the break demonstrating the effect in action, complete with cats.
We like to see people pushing the boundaries of what is possible with their microcontroller I/O lines, it furthers our collective knowledge as a community. We’ve seen people making TV transmitters from ESP8266s, and not so long ago a Raspberry Pi ADC port as further examples. Please, keep them coming!
Electrospinning is a fascinating process where a high voltage potential is applied between a conductive emitter nozzle and a collector screen. A polymer solution is then slowly dispensed from the nozzle. The repulsion of negative charges in the solution forces fine fibers emanate from the liquid. Those fibers are then rapidly accelerated towards the collector screen by the electric field while being stretched and thinned down to a few hundred nanometers in diameter. The large surface area of the fine fibers lets them dry during their flight towards the collector screen, where they build up to a fine, fabric-like material. We’ve noticed that electrospinning is hoped to enable fully automated manufacturing of wearable textiles in the future.
[Douglas Miller] already has experience cooking up small batches of microscopic fibers. He’s already made carbon nanotubes in his microwave. The next step is turning those nanotubes into materials and fabrics in alow-cost, open source electrospinning machine, his entry for the Hackaday Prize.
As always in fundamental research projects, a whole lot of parameters have to be tuned just right. To speed up the process of finding suitable values for the electric potential, dosing feed rate, emitter to collector plate distance, temperature, and humidity, [Douglas] build his machine with a CNC controlled vertical axis and syringe pump, that can dispense even the smallest amounts of a given solutions accurately. Temperature and humidity control will be added as the project progresses. A host software and GUI allows for easy control of all parameters and will also save and recall presets for different spinning solutions once everything has been dialed in. [Douglas] already ran a few tests, spraying saline solution from an old 3D printer nozzle, and we can soon expect first tests with polymer solutions from the better-suited syringe nozzles he installed.
To keep the build affordable and easy to reproduce for other makers, [Douglas] uses available materials and came up with a few design tricks that could also be applied to other projects. The belt-driven vertical axis is based on PVC pipes, on which a 3D-printed bushing block slides up and down, adjusting the distance between the nozzle and the collector plate. An acrylic door with a safety switch prevents the polymer spray from escaping from the spinning chamber. In the heart of the machine sits an Arduino Uno with a gShield, controlling the stepper motors and talking to the host computer. The 3D-printed syringe pump, a custom design, swings out from the side of the machine to allow for easy refilling. Submerged in mineral oil, which may have been chosen to reduce the risk of overheating and arcing, lies a half-wave series voltage multiplier, cranking up the voltage from an AC power supply to a maximum of 30 kV DC.
