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Amateur radio has been a popular hobby for decades, and can be an expensive rabbit hole to fall down.

It’s easy to spend thousands of dollars on equipment, such as the FLEX-6600 series of SDR (software-defined radio) transceivers, and even then you still need a Maestro Control Console or PC in order to interact with it. Unless, that is, you have a Teensy 4.1, the Arduino Flex library, and a little ingenuity, as PJRC forum member KD0RC demonstrated with their TeensyMaestro Controller for Flex 6000 ham radios.

The TeensyMaestro leverages the Flex TCP/IP API to control the transceiver, via an interface built from nine mechanical encoders, two optical encoders, 20 multiplexed switches, and an Adafruit HX8357 TFT touchscreen. The snazzy-looking front panel is simply aluminum covered with laser-printed graphics under a clear plastic shield. A GitHub repo is available with schematic, BOM, builder’s guide, and user manual.

The average Major League Baseball pitcher throws the ball at over 90mph, with the number of 100mph pitches increasing in recent years. But the average cannon…or…well, we’re not sure if it’s average, but this cannon in particular fires balls at up to 135mph…maybe?

Whether or not it does, jpswensen has created an Teensy 4.1-based advanced measurement system that can calculate the velocity of baseballs being shot out of  cannon at up to 135mph!

The system consists of four emitter boards and four sensor boards. Each emitter is comprised of 34 laser diodes, with a corresponding 34 PIN photodiodes and transimpedance amplifier circuits on each sensor board being read by a Teensy 4.1. The Teensy-powered sensor boards are in turn connected via I2C to a Raspberry Pi 4, which performs the necessary calculations to determine the incoming and rebound velocity. Watch the whole system in action in this super-slow motion video.

We love seeing all of the many creative projects that folks use Teensy boards for, and the plethora of musical instruments bring us particular joy. This is especially the case with ETMoody3’s capacitive touch MIDI keytar.

The birch plywood body resembles the classic 80s styling of the Yamaha SHS-10 Sholky (Shoulder Keyboard), but the underlying ideas could be applied to any form factor. Four MPR121 capacitive touch sensor breakouts on each of the four available addresses handle the 37 keys, with an ST7789 LCD and seven additional touch sensors providing the user interface. An ADS1015 ADC and simple LED/photoresistor pairing in the headstock serves as an optical pitch bend. The keys are copper foil tape, covered with vinyl. A pair of XBee radios provide wireless communication to a Teensy 3.6-powered receiver, which in turn outputs MIDI. The BOM, blueprint, and source for both the controller and receiver can be found on GitHub, including bitmap data for the adorable namesake Platypus who is depicted on the LCD rocking out with its own tiny keytar!

Model rockets are a great way to capture the thrill of the awe-inspiring full scale vehicles in a safe, budget-friendly form factor. But as the real thing evolves and adopts new features, enthusiasts like T-Zero Systems scale these advanced systems down to fit the miniature version,

as is the case with their 1/70th scale Falcon 9 rocket, which features real thrust vector control (TVC) like the big one.

The Teensy 3.6-powered guidance system even has aspirations to land vertically, although unfortunately the code is not available due to legal concerns. STL files and more information are available on the T-Zero Systems Patreon, however. The latest evolution of the software, which apparently borrows code from the space shuttle, can be seen in the video below.

We’ve covered PJRC forum member CryHam’s Teensy 3.2-powered KC Keyboard Controller before, but now it’s back with a significant upgrade, in the form of the Teensy 4.0-based K.C.4 controller for matrix keyboards.

If you have an inexpensive dome-switch keyboard that lacks the features of higher-end mechanical keebs, like key mapping, layers, macros, and a screen that can run demos, games, and an RTC-backed clock…although…wait — we’re not sure we’ve seen that on any keyboard, come to think of it?! — so maybe give K.C.4 a look regardless!

Configuration starts as simply as a Teensy 4.0 and ILI9341 TFT LCD display. Adding serial EEPROM such as a 25LC256, a DS18B20 1-wire temperature sensor and 4.7k resistor, and LED/photoresistor will get you all of the bells and whistles, such as temperature graphs, and an external 5V power supply will even let you display and retain data without PC power.

A wealth of information can be found on the project page, with source and schematic available on GitHub, and various demos available on YouTube, as well as the one below.

What do you get when you cross a Teensy 3.6 with a Raspberry Pi 3B, 2448 RGB LEDs, a thousand pieces of origami, and a papier-mâché sculpture?

If you’re PJRC forum member beil, the answer is Wefted Waveforms, an “interdisciplinary light sculpture” completed as part of their Visual Arts degree at Queensland University of Technology in Brisbane, Australia.

The project uses gLEDiator to animate the LEDs, along with our OctoWS2811 Adaptor to wire them up. A detailed write-up can be found on the Core Electronics project site, and a rather hypnotic video of the Wefted Waveforms in action can be seen in the video below.

Mike Mayfield’s 1971 Star Trek was a strategy game designed for computers with no graphical display.

While Teensy boards are more than capable of driving advanced graphical displays, PJRC forum member jim lee ported the BASIC source to Arduino with the help of Arduino forum member WildBill, and then added a GUI to provide keyboard input, and … an entire Teensy 3.2-based handheld unit for on-the-go play. The source, available on GitHub, also provides a version that runs on the Arduino IDE’s serial monitor, so that you can try it without any extra hardware.

A popular meme pokes fun at the DIY mechanical keyboard community by suggesting that enthusiasts must surely realize significant savings by building their own keyboards rather than purchasing a commodity preassembled unit,

whereas anyone who has ever even dipped their toe into that rabbit hole knows that this is typically far from the case. Rather than toss some keycaps, switches, a board and a case into a shopping cart and whacking them all together, however, PJRC forum user stefan.jakobsson took things to the next level with a scratch-built, Teensy LC-based 60% keeb.

We’re not sure what switches or caps are in use here, but the plate is 3d-printed, and the matrix is hand-soldered, dead bug-style, rather than using a PCB. A bespoke 1.5 steel plate forms the bottom case. Custom firmware, written using the Keyboard class, supports a standard layer plus second Fn layer, and has a simple built in debouncing handler. Source code is available in the thread, although Stefan is still working through some issues with sleep mode.

‘Twas the night before Christmas, when all through the house, not a creature was stirring, not even a mouse – which was frustrating,

because the Mr. Christmas “The Night Before Christmas House” was supposed to be playing audio and flashing light bulbs that correspond to the story, but a previous failed repair attempt had rendered it inoperable. That is, until PJRC forum member edseitz replaced the cassette player and associated electronics with a Teensy 3.6 and Prop Shield!

The seventeen light bulbs were replaced with LEDs, and a custom class was added to simulate the warming and dimming of traditional bulbs. The Teensy’s microSD storage was ideal for .WAV files of the original cassette audio, with their playback facilitated by the Prop Sheild’s integrated 2-watt audio amp. And we heard edseitz exclaim, as he hid the wiring out of sight – “Happy Christmas to all, and to all a good night!”

We’ve covered plenty of Teensy-powered grooveboxes on the blog here before, but this Reddit post unveiling the Audio Enjoyer XR-1 really caught our eye. If you’re looking to go DAWless, this Teensy 4.1-powered drum machine, sampler, and synthesizer looks like a great all-in-one machine.

Modeled after Roland TR-909 sequencing conventions, it has 16 banks of 16 patterns of 16 tracks, with up to 64 steps per track.

Around back are standard stereo in/out and 5-pin DIN MIDI jacks, and eight 0-10V CV/gate outputs. Mono RAW or stereo WAV samples are stored on microSD, along with project data. The unit also features a capacitive touch keyboard and hard buttons arranged in an MPC-style 4×4 grid, plus an OLED display for presenting the UI. A demonstration of the XR-1 can be seen below, and Audio Enjoyer have a signup form on their website for more info.