Hacklet 126 – Teensy Projects

The Arduino has proved to be a great platform for electronics projects. The same goes for the Raspberry Pi. However, there are some projects that fall in the gap between these two options. Projects that need more memory or processing power than the ATmega microcontrollers have to offer, but not so much as to require a full Linux/ARM powerhouse. For those projects, there is the Teensy series. [Paul Stoffregen] created these lilliputian boards, and he’s been adding features ever since. The thousands of Teensy projects out there stand as proof that these little boards have been well received by the hacker community. This week’s Hacklet is about some of the best Teensy projects on Hackaday.io!

beatsWe start with [Jonathan Payne] and Beats by Teensy. Beats is an all in one music machine. A sampler, sequencer, and MIDI control surface; all powered by the Teensy 3.1 and the Teensy Audio Board. The audio board gives Beats the ability to record and playback 16 bit audio at a sampling rate of  up to 44.1 kHz. [Jonathan’s] inspiration came from devices such as the Akai MPC, and the MIDI Fighter. He utilized the incredible Teensy audio library on the software side. A project like this needs a serious case. [Jonathan] designed and built the perfect panel and case utilizing arcade buttons and a 128×64 LCD from Adafruit.

sabNext we have [RF William Hollender] and Teensy Super Audio Board. Not satisfied with CD quality 44.1 kHz audio, [William] decided to add a high quality audio codec to Teensy’s bag of tricks. He picked the CS4272 codec from Cirrus Logic. Capable of sampling rates up to 192 kHz, with a THD+N of -100 db, this codec should please all but the most discerning audiophiles. The high noise immune design doesn’t stop there though. [William’s] design isolated the Teensy and the rest of the interfaces from the codec to prevent ground loops. Connectivity is via standard I2S for the audio stream and I2C for control. This means the super audio board can be used with Raspberry Pi’s and the like.

spinoNext up is [Spino] with Spino. Teensy boards can do a lot more than just audio. Spino is a POV display with 32 spinning RGB LEDs. Spino can do more than just show pretty pictures though. With a Teensy 3.2 and bluetooth radio on board, the spino team is able to play games on their display. LEDs don’t work exactly like CRTs and LCDs though, so some color changes were necessary. The team utilized cell shading with a sobel filter to make Doom look even better than ever. The Teensy is even powerful enough to handle live webcam video sent over USB. The video is rendered and displayed on the spinning LEDs.

megsyFinally we have [Tim Trzepacz] with Megsy? A homebrew Teensy 3++. [Tim] is working on Megsy as part of his  residency at the Supplyframe Design Lab. Teensy’s have lots of edge mounted IO pins. There isn’t enough real estate for all the pins though, so some are routed to pads on the bottom. Megsy is a Teensy carrier board that breaks these pads out to pins. The idea is to solder the Teensy directly do the Megsy. As [Tim] calls it, “a poor man’s BGA”. The problem is getting the solder hot enough to melt while sandwiched between two insulating PCBs. [Tim’s] first attempt netted him a rather scorched Megsy board. Blacked as it may have been, the board did work!

If you want to see more Teensy projects, check out our new Teensy projects list. Notice 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!

Artificial Skylight Brings Sunlight To Any Room

Humans aren’t supposed to be cooped up indoors all day, but who wants to be bothered by UV rays, insects, allergens, traffic, physical activity, and other people? On the other hand, a gloomy living space generally inhibits productivity — if not making it difficult to find what you’re looking for. So, if you’re looking to illuminate any room in your place, and you have the cash and the patience to wait for its widespread release, CoeLux is a skylight that needs no sky or sun — not that you’ll be able to tell the difference.

The Italian developers [CoeLux Srl] are perhaps wisely remaining tight-lipped on how the effect is achieved, but confirm that nanoparticles in the skylight mimic the effect of atmospheric fluctuations, compressing that vast deep blue into a few milimetres while maintaining the perception of infinite depth.

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Now is the Golden Age of Artisanal, Non-Traditional Tube Amps

Earlier in the month, [Elliot Williams] quipped that it had been far too long since we saw a VFD-based amplifier build. Well, that dry spell is over. This week, [kodera2t] started showing off his design for a VFD headphone amp.

Here’s the thing, this isn’t using old surplus vacuum fluorescent displays. This is actually a new part. We first covered it about 18 months ago when Korg and Noritake announced the NuTube. It’s the VFD form factor you would find in old stereo and lab equipment, but housed in the familiar glass case is a triode specifically designed for that purpose.

Check out [kodera2t’s] video below where he walks through the schematic for his amplifier. Since making that video he has populated the boards and taken it for a spin — no video of that yet but we’re going to keep a watchful eye for a follow-up. Since these parts can be reliably sourced he’s even planning to sell it in his Tindie store. If you want to play around with this new tube that’s a pretty easy way to get the tube and support hardware all in one shot. This is not a hack, it’s being used for exactly what Korg and Noritake designed it to do, but we hope to see a few of these kits hacked for specific tastes in amp design. If you do that (or any other VFD hacking) we want to hear about it!

And now for the litany of non-traditional VFD amps we’ve grown to love. There is the Nixie amp where [Elliot] made the quip I mentioned above, here’s an old radio VFD amp project, in this one a VCR was the donor, and this from wayback that gives a great background on how this all works.

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See a Cheap Smoker get an Automation Power Up

[Jason] learned a lot by successfully automating this meat smoker. This is just the first step in [Jason’s] smoker project. He decided to begin by hacking a cheaper charcoal-fed unit first, before setting his sights on building his own automatic pellet-fed smoker. With a charcoal smoker it’s all about managing the airflow to that hot bed of coals.

automated-meat-smoker-air-valve
Custom mount for servo was actually one of the more challenging things to get just right.

[Jason] started by making sure the bottom was sealed off from stray airflow, then he cut a hole into the charcoal pan and attached a length of steel pipe. The opposite end of the pipe has a fan. Inside the pipe there is a baffle separating the fan from the charcoal pan. The servo motor shown here controls that valve.

The pipe is how air is introduced into the smoker, with the fan and valve to control the flow rate. The more air, the higher the temperature. The hunk of pipe was left uncut and works fine but is much longer than needed; [Jason says] the pipe is perfectly cool to the touch only a foot and a half away from the smoker.

With the actuators in place he needed a feedback loop. A thermocouple installed into the lid of the smoker is monitored by an Arduino running a PID control loop. This predicts the temperature change and adjusts the baffle and fan to avoid overshooting the target temp. The last piece of hardware is a temperature probe inside the meat itself. With the regulation of the smoker’s temperature taken care of and the meat’s internal temperature being monitored, the learning (and cooking) process is well underway.

There are many, many smoker automation projects out there. Some smokers are home-made electric ones using flower pots, and some focus more on modifying off the shelf units. In a way, every PID controlled smoker is the same, yet they end up with different problems to solve during their creation. There is no better way to learn PID than putting it into practice, and this way to you get a tasty treat for your efforts.

Hackaday Prize Entry: Catch The IMSI Catchers

An IMSI catcher is an illicit mobile phone base station designed to intercept the traffic from nearby mobile phones by persuading them to connect to it rather than the real phone company  tower. The IMSI in the name stands for International Mobile Subscriber Identity, a unique global identifier that all mobile phones have. IMSI catchers are typically used by government agencies to detect and track people at particular locations, and are thus the subject of some controversy.

As is so often the case when a  piece of surveillance technology is used in a controversial manner there is a counter-effort against it. The IMSI catchers have spawned the subject of this post, an IMSI catcher detector app for Android. It’s a work-in-progress at the moment with code posted in its GitHub repository, but it is still an interesting look into this rather shadowy world.

How them you might ask, does this app hope to detect the fake base stations? In the first case, it will check the identity of the station it is connected to against a database of known cell towers. Then it will try to identify any unusual behaviour from the base station by analysing its traffic and signal strength. Finally it will endeavour to spot anomalies in the implementation of the cell phone protocols that might differentiate the fake from the real tower.

They have made some progress but stress that the app is in alpha stage at the moment, and needs a lot more work. They’re thus inviting Android developers to join the project. Still, working on projects is what the Hackaday Prize is all about.

Home-made Adjustable Knife Jig

When sharpening a knife, it is critical to have the knife at the right angle. A knife jig handles this for you, letting you focus on getting the edge right. You could just buy one, but where’s the fun in that? [origamimavin] decided to make his own adjustable knife jig using bits he bought from the hardware store for $27, and which you might have in your junk pile. Fortunately for us, he’s written up the process in excellent detail, explaining the how and why of each step.

He used a couple of tools that you might not have lying around (a bandsaw and a belt sander), but these could be easily replaced with their manual cousins, or your local hackerspace will doubtless provide you access to them. Either way, it’s a simple build which could help your knives keep their clean, sharp edge for years to come.

From Audio, To 3D Printed Sculpture, And Back Again

Have you ever wondered what a song looks like? What it feels like in your hands?

Those odd questions have an answer that has taken shape over at [Reify], which has developed a way to turn sound waves into 3D-printed sculptures. These visualizations made manifest can be made from any audio — speeches, the ambience of a forest, classical music, a rocket launch — and rendered in coconut husk, plastic, bronze and more.

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