Hacklet 117 – NFC Projects

Near Field Communication (NFC) is something we take for granted these days. Nearly all smartphones have it. We even have NFC interfaces for all our favorite development boards. NFC’s history goes back all the way to 1997, when an early version was used in Star Wars special edition toys. Radio Frequency Identification (RFID), which NFC builds on, goes back even further. The patent citation trail leads all the way back to 1983 in a patent awarded to [Charles Walton]. NFC is much more than RFID though. The idea of two way communication between devices opens up tons of possibilities for projects and hacks. This week on the Hacklet we’re checking out some of the best NFC projects on Hackaday.io!

ctrl0We start with [Patrick] and Ctrl-O. Somewhere in the hackerspace bible there is a clause that states “Thou shalt build an electronic access control system”. In [Patrick’s] case, a door lock became a complex membership subscription management database. Members who have paid can use an NFC tag to gain access to the hackerspace. The system consists of a Raspberry Pi with an NFC interface. A relay allows the Pi to control the door lock. The Pi can be manually configured through a web interface. It connects to Paypal to verify that each user’s membership has actually been paid. Of course a project like this is never done. The last we heard from [Patrick], he was planning future upgrades such as startup company memberships with multiple people.

keyduinoNext up is [Pierre Charlier] and KeyDuino. KeyDuino is an Arduino compatible board with all the NFC hardware baked right in. The board is based upon the Arduino Leonardo, with an ATmega32u4 processor. [Pierre] must be on to something, because the KeyDuino had a successful Kickstarter back in 2015. It’s also open source hardware, so you can build your own whenever you want. The real gem is checking out [Pierre’s] other projects. He’s documented all his KeyDuino example projects right on Hackaday.io. These include an NFC Controlled infinity mirror coffee table, a locking wooden gift box, and NFC controlled car door locks, just to name a few.

nfcringNext we have [John McLear] with 2016 NFC Ring. [John] jumped into wearable technology with one of the toughest form factors imaginable – a ring. Between the tiny amount of space and the lack of batteries, you might think there isn’t much you can do with a ring. Undaunted, [John] managed to fit two NXP NFC chips and their antennas inside a standard ring. This is the upgraded 2016 version of the ring. [John] was nice enough to supply several hundred of the earlier models to hackers at the Hackaday Supercon back in 2015. [John’s] rings would be hard for the average hacker to reproduce. [Sean Hodgins] comes to the rescue here with his own project, DIY NFC Bentwood Ring.

pressureFinally, we have [CaptMcAllister] with RFID air pressure sensor. As the name implies, this sensor measures air pressure. It could be in open air, a tire, or even a football used by the New England Patriots. Sure, cars all have Tire Pressure Monitoring Systems (TPMS) sensors which do something similar. [CaptMcAllister’s] design has one important difference – it has no batteries. The heart of the system is a Texas Instruments RF430FRL15X, a device with the NFC radio and a low power MSP430 microcontroller in one chip. The system is energy harvesting, being powered by an external reader. As you can imagine, tuning the antenna was critical to this design. You can read all about it in [CaptMcAllister’s] 24 project logs.

If you want to see more NFC projects and hacks, check out our new near field communication projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 116 – Audio Projects

If the first circuit a hacker builds is an LED blinker, the second one has to be a noisemaker of some sort. From simple buzzers to the fabled Atari punk console, and guitar effects to digitizing circuits, hackers, makers and engineers have been building incredible audio projects for decades. This week the Hacklet covers some of the best audio projects on Hackaday.io!

vumeterWe start with [K.C. Lee] and Automatic audio source switching. Two audio sources, one amplifier and speaker system; this is the problem [K.C. Lee] is facing. He listens to audio from his computer and TV, but doesn’t need to have both connected at the same time. Currently he’s using a DPDT switch to change inputs. Rather than manually flip the switch, [K.C. Lee] created this project to automatically swap sources for him. He’s using an STM32F030F4 ARM processor as the brains of the operation. The ADCs on the microcontroller monitor both sources and pick the currently active one. With all that processing power, and a Nokia LCD as an output, it would be a crime to not add some cool features. The source switcher also displays a spectrum analyzer, a VU meter, date, and time. It even will attenuate loud sources like webpages that start blasting audio.


muzzNext up is [Adam Vadala-Roth] with Audio Blox: Experiments in Analog Audio Design. [Adam] has 32 projects and counting up on Hackaday.io. His interests cover everything from LEDs to 3D printing to solar to hydroponics. Audio Blox is a project he uses as his engineer’s notebook for analog audio projects. It is a great way to view a hacker figuring out what works and what doesn’t. His current project is a 4 board modular version of the Big Muff Pi guitar pedal. He’s broken this classic guitar effect down to an input board, a clipping board, a tone control, and an output stage. His PCB layouts, schematics, and explanations are always a treat to view and read!

pauldioNext we have [Paul Stoffregen] with Teensy Audio Library. For those not in the know, [Paul] is the creator of the Teensy family of boards, which started as an Arduino on steroids, and has morphed into something even more powerful. This project documents the audio library [Paul] created for the Freescale/NXP ARM processor which powers the Teensy 3.1. Multiple audio files playing at once, delays, and effects, are just a few things this library can do. If you’re new to the audio library, definitely check out [Paul’s] companion project
Microcontroller Audio Workshop & HaD Supercon 2015. This project is an online version of the workshop [Paul] ran at the 2015 Hackaday Supercon in San Francisco.

drdacFinally we have [drewrisinger] with DrDAC USB Audio DAC. DrDac is a high quality DAC board which provides a USB powered audio output for any PC. Computers these days are built down to a price. This means that lower quality audio components are often used. Couple this with the fact that computers are an electrically noisy place, and you get less than stellar audio. Good enough for the masses, but not quite up to par if you want to listen to studio quality audio. DrDAC houses a PCM2706 audio DAC and quality support components in a 3D printed case. DrDAC was inspired by [cobaltmute’s] pupDAC.

If you want to see more audio projects and hacks, check out our new audio projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Ask Hackaday: Does Apple Know Jack About Headphones?

If you’ve watched the tech news these last few months, you probably have noticed the rumors that Apple is expected to dump the headphone jack on the upcoming iPhone 7. They’re not alone either. On the Android side, Motorola has announced the Moto Z will not have a jack. Chinese manufacturer LeEco has introduced several new phones sans phone jack. So what does this mean for all of us?

This isn’t the first time a cell phone company has tried to design out the headphone jack. Anyone remember HTC’s extUSB, which was used on the Android G1? Nokia tried it with their POP Port. Sony Ericsson’s attempt was the FastPort. Samsung tried a dizzying array of multi-pin connectors. HP/Palm used a magnetic adapter on their Veer. Apple themselves tried to reinvent the headphone jack by recessing it in the original iPhone, breaking compatibility with most of the offerings on the market. All of these manufacturers eventually went with the tried and true ⅛” headphone jack. Many of these connectors were switched over during an odd time in history where Bluetooth was overtaking wired “hands-free kits”, and phones were gaining the ability to play mp3 files.

Continue reading “Ask Hackaday: Does Apple Know Jack About Headphones?”

Parallel Compressors for Sandblasting without Crashing Your Grid

[Hannah] is restoring a 1962 Volkswagen Bug. The goal is to get the car on the road in time for her driver’s test. This is no easy task, as the lower 3 inches of all the body work is rusted out, and the engine is…. well, missing. Basically, the car needs a frame off restoration. This means that [Hannah] will have a lot of metal bodywork to clean up. One of the easiest ways to do that is sandblasting.

Large scale sandblasting is a bit different from most air-powered operations. Sandblasting needs only a modest air pressure, but a high air flow. [Hannah] need 25 Sustained Cubic Feet Per Minute (SCFM) at 80 PSI for sandblasting. Most compressors can easily supply that pressure, but 25 SCFM is asking quite a lot. She could go with an expensive 3 phase unit, or rent a diesel screw compressor. However, [Hannah] decided to connect 4 compressors in parallel to give her the flow she needed.

Connecting the air outputs in parallel is easy. The problem is the electricity. Each compressor is rated for 9 amps while running. They draw quite a bit more while starting up. The compressors have to be wired to individual 15 amp circuits to avoid blowing fuses. They also need to be started in sequence so they don’t pull down the AC for the entire house while starting.

Hannah could have used any sort of delay for this, but she chose an Arduino. The Arduino’s wall wart is wired up to the master compressor. Turning on the master powers up the Arduino which immediately starts a 2 second delay. When the delay times out, the Arduino fires up the second compressor. After several delay loops, all 4 compressors are running together.

hannah-schThe Arduino’s GPIO pins can’t handle 9 amp AC loads, so [Hannah] wired them to TIP120 transistors. The TIP120s drive low power relays, which in turn drive high current air conditioning relays. The system works quite well, as can be seen in the video below the break.

If you’re interested in air compressor projects, check out this setup made from an old refrigerator compressor. For more background on the TIP120, check out this article about these useful transistors.

Continue reading “Parallel Compressors for Sandblasting without Crashing Your Grid”

TritiLED Lights Up The Night, Doesn’t Make You Glow

Tritium, or 3H is an isotope of hydrogen which has been used as everything from radiolabel in analytical chemistry to a booster to kickstart the chain reaction of nuclear weapons. Lately tritium’s most common use has been in key chains and jewelry. A small amount of tritium is stored in a phosphor coated glass tube. The beta decay of the tritium causes the phosphor to glow. The entire device is called a Gaseous Tritium Light Source (GTLS).

In the USA, GTLS devices are only allowed to be used in specific cases such as watches, compasses, and gun sights (MURICA!). Key chains and jewelry are considered frivolous uses and are prohibited by the nuclear regulatory commission. Of course, you can still order them from overseas websites.

The safety of GLTS devices have been hotly debated on the internet for years. They’re generally safe, unless you break the glass. That said, we’re happy getting our radiation exposure through cool hacks, rather than carrying a low-level source around in our pockets.

Enter [Ted Yapo], an amateur astronomer. After tripping over his telescope tripod one time too many, he decided to take matters into his own hands. He’s designing TritiLED, a dim LED light source which can last for years. [Ted] is using a  Luxeon Z LED, driven with PWM by a PIC 12F508 8 bit microcontroller. Running at 26.3 μA, he estimates about a year of run time on a CR2032 watch battery, or a whopping 15 years on a pair of lithium AA cells. Sure he could have done it with a 555 timer, but using a micro means more features are just a few lines of code away. [Ted] took advantage of this by adding a high brightness mode, blink modes, and an exponential decay mode, which emulates the decay of GLTSs.

Best of all it’s all open source. [Ted] is publishing under the (CC-BY-SA) license on Hackaday.io.

Hacklet 115 – More Quick Tool Hacks

Some of the best hacks are the tools people make to help them complete a project. I last looked at quick tool hacks back in Hacklet 53. Hackers have been busy since then, and new projects have inspired new tools. This week on the Hacklet, I’m taking  a look at some of the best new quick tool hacks on Hackaday.io.

pickupWe start with [rawe] and aquarium pump vacuum pickup tool. Tweezers work great for resistors and caps, but once you start trying to place chips and other large parts, things quickly become frustrating. Commercial machines use high dollar vacuum pickup devices to hold parts. [rawe] built his own version using a cheap Chinese hand pickup tool and an aquarium pump. With some pumps, switching from air to vacuum is easy. Not with [rawe’s] pump. He had to break out the rotary tool and epoxy to make things work. The end result was worth it, a vacuum pickup tool for less than 10 Euro.



Next we have [David Spinden] with ViaConnect Circuit Board Test Tool, his entry in the 2016 Hackaday Prize. [David] wanted a spring loaded pin which could be used in .100 holes in printed circuit boards. He ended up using pins from one connector, shell from another, and packaging the whole thing up into a new tool. ViaConnect essentially makes any PCB as easy to use as a solderless breadboard. No headers required. This is great both for testing new designs and for the education sector.

Allen tool holderNext up is our favorite quick tool hacker, [Alex Rich] with Improved Allen Wrench / Hex Key Holder. If [Alex] looks familiar, that’s because he’s the creator of the Stickvise. This time he’s come up with a new way to store and organize your Allen wrenches. Inspired by a similar device seen on a YouTube video from [Tom Lipton], [Alex] opened up his CAD software and started designing. The original used a steel spring to keep the wrenches in place. [Alex] switched the spring to a rubber o-ring. The o-ring securely holds the wrenches, but allows them to be easily pulled out for use. Of course the design is open source, so building your own is only a couple of hours of printing away!



solderdoodFinally we have [Solarcycle] with Cordless Foam Cutting Tool – USB Rechargeable. Soldering irons make a lot of heat in a small area to melt metal. Foam cutters make heat in a larger area to cut Styrofoam. [Solarcycle] saw the relation and converted a Solderdoodle Pro cordless soldering iron into a banjo style hot wire foam cutter. A barrel connector converts the soldering iron tip output to two stiff wires. The stiff wires carry current to a 3 cm length of Kanthal iron-chromium-aluminium (FeCrAl) heating element wire. If you don’t have any Kanthal around, ask your local vape enthusiast – they have tons of it. The result is the perfect hand-held tool for carving and sculpting in foam. Just make sure to have lots of ventilation.

If you want to see more of these hacks, check out our newly updated quick tool hacks list! See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Triple Monitor Travel Battlestation

[AbyssalUnderlord’s] schedule has him packing up and moving between school, home, and internships every three months. Not an easy task when your computer is a triple monitor CAD and gaming powerhouse. To make his moves easier, he built this portable computer / monitor frame.

The design started with a CAD model. The basic materials for the build are aluminum angle and steel-slotted angle stock. There was no welding involved in this build. Pop rivets, nuts, and bolts hold just about everything together. An angle grinder was used for all of the cutting. [AbyssalUnderlord] used drawer slides to move his monitors from stored to deployed position. The small red extensions at the end of the drawer slides allow the monitors to be positioned in a standard 3 wide triple monitor setup. It’s a clever design.

This schedule isn’t going to last forever so [AbyssalUnderlord] didn’t want to make any permanent mods to his tower or monitors. Blue camping foam acts as a cushion between the hardware and the new case.

We’ll admit that this isn’t the prettiest of builds, but it looks plenty rugged and it gets the job done. As mentioned in the Reddit thread, a few coats of spray paint would go a long way toward improving the aesthetics. Just don’t spend too much time playing Overwatch, [AbyssalUnderlord].

If you like DIY portable setups, check this Transformers-themed portable workbench, or our Hacklet all about portable work stations and toolboxes.