Blog Posts

Members of the Teensy community will be familiar with our Audio Adaptor Board, which adds CD-quality sound to your Teensy 4.x projects.

It uses the low-power SGTL5000 stereo codec from NXP, but forum user Bob Larkin performed a detailed exploration of this chip’s performance vs. TI’s PCM1808, resulting in the creation of his own audio adapter board based on the TI ADC.

One of the challenges Bob encountered was keeping the same footprint as the original, so they can be used interchangeably. The resulting board lacks microphone hardware, an SD card socket, or the original’s pads for adding optional RAM, but offers dual stereo audio inputs and outputs instead of single, and based on Bob’s analysis, the dynamic range of the ADC is significantly improved. Example code is provided, since the hardware functionality differs significantly, and in addition to Kicad files being available on Bob’s site, the unpopulated PCB can be conveniently purchased directly from OSH Park. Find out more and join the conversation in the Audio Adaptor PCM1808/5102A thread on the PJRC forums!

Various makers have created “working” Transformers over the years, but most of them can’t be ridden in since they’re full of … robot.

YouTuber James Bruton, who we’ve featured on the blog before, solved this problem by creating a Transformer that you can ride on, like a Power Wheels car. He chose a Teensy 4.1 to power his transforming Power Wheels.

The Teensy controls not only the motors and servos involved in transforming into ambulatory form, but also the fancy blue LEDs that give the futuristic police cruiser-inspired-rig a little extra flair. “Hoverboard” wheels provide propulsion in car mode. Code and CAD files are available on GitHub and as always, a fantastic video explaining how the entire project came together is available on YouTube.

Haybur has shared a template to help developers get started with Teensy-based music visualization projects.

While it is designed for use with a custom PCB, it can be adapted to any Teensy/Audio Adaptor Board project. The project assumes a 16×16 LED matrix, and takes care of all the FFT beat detection and timing, facilitating animated responses based on the FFT data.

Pattern lists allow the storage of animations for application to various triggers or situations.

But this is just a starting point — Haybur has used this system for large installations such as the two 4×4′ panels below, and more. The template is available on GitHub, and more information and pictures can be found via the original forum thread.

Brad shares a project from the depths of COVID lockdown: a budget DIY mechanical keyboard. As a student, Brad yearned for a fancy mech, but a lack of funds resulted in a far more impressive route: soldering a Teensy directly to the switches of a completely DIY typing tool.

The soldering alone took about three days, but it lasted for several years, until Brad had the budget for a commercial keeb, and still brings back fond memories. Now working on combat robotics, Brad relishes every opportunity to reuse the knowledge gained from this early project.

The bizarre Suzuki Omnichord looks a bit like a prop from a weird 80s sci-fi show, but is in fact a real instrument, developed to create harp-like arpeggios, and first introduced in 1981, then re-introduced as the OM-108 in 2024.

Those familiar with its odd shape and interface will see immediate echoes in Benjamin Poilve’s open-source minichord synthesizer.

The pocket-sized instrument allows anyone to create pleasant-sounding chord progressions, without requiring extensive knowledge of music theory. Strumming the “harp touch zone” allows any of twelve notes to be triggered and, with continued contact, held. The Teensy 4.0-based instrument can also act as a MIDI device over USB. Having won Seeed’s Co-Create competition, the minichord is now available for purchase. The hardware and firmware to build your own is available on GitHub, and excellent assembly instructions and a user manual can be found on the project’s web site. You can also connect with the project creator on the PJRC forums.

We’ve all dreamed of flight, but Nick Rehm’s dRehmFlight VTOL brings that dream closer for hobbyists and hackers looking to get their weird contraptions airborne.

Based on a Teensy 4.0 plus TDK MPU-6050 six-axis IMU, the project is intended to teach flight control and stabilization concepts, rather than competing with more specific platforms.

Out of the box, dRehmFlight VTOL supports six speed controllers over OneShot125, with a further seven PWMs for servos or traditional ESCs. The code is extensively documented in order to facilitate learning, and a further 72 pages of documentation, as well as extensive YouTube tutorials and examples make getting started as quick and painless as possible.

Yang Zhang, Wolf Kienzle, Yanjun Ma, Shiu S. Ng, Hrvoje Benko, and Chris Harrison have created ActiTouch: robust touch detection for on-skin AR/VR interfaces. Instead of traditional handheld controllers, the system uses the body as an input device.

A smartwatch-style wristband contains a Kinetis K20 microcontroller running firmware prototyped with Teensy and a AD5930 waveform generator, as well as a LiPo battery to power the system. Electrodes on the wrist and headset, combined with computer vision enables both high tracking precision and robust touch detection, permitting touchscreen-like interactions on the wearer’s own skin. Learn more on Chris’s web site, in the original paper, or in the video below.

Adrian wanted to create a silly surprise for their friend and avid player of the rhythm game OSU!, with the bonus goal of getting a chance to learn about electronics. The result of this was an adorable two-key keyboard based around a Teensy.

Combining some spare keyboard switches and a 3d-printed case and caps with Teensy’s built-in Human Interface Device (HID) mode, the gag gift gives off a surprisingly professional vibe, not to mention a fair number of laughs. Despite being intended as a joke, the keyboard could be useful for video editing, or … using Stack Overflow!

Aaron Todd is the eponymous hacker behind the One Hacker Band — a social media sensation that uses electronics to make musical instruments play themselves via MIDI. Guitars, percussion, a Novation keyboard, vocals — OHB’s got it all, and it’s all powered by Teensy!

Aaron takes us behind the scenes of the band’s servo-controlled self-playing keyboard in the video below:

We’ll be taking a deeper dive into some of the individual instruments, but for now, check them out on all the socials, and enjoy this cover of Come as You Are by Nirvana!

YouTuber James Bruton wanted to create a prosthetic arm with natural control. At first, the idea was to use a brain-computer interface, but obtaining reliable data this way proved more difficult than expected.

So James pivoted to using machine learning to train the arm to mimic his real arm based on the position and posture of other parts of his body — using a bunch of Teensy boards while he was at it!

The motion capture solution is based on five Teensy LC boards with TDK MPU-6050 six-axis gyro/accelerometer sensors for motion, with the four “limb” units also adding AMS AS5047 magnetic rotary position sensors for joint position. A central Teensy 4.1 connected to each of them orchestrates data collection. Dynamixel servo actuators power the arm using an Arduino MKR-style shield connected to the 4.1. After training the system using all of his real limbs, James then swapped in the 3d-printed prosthetic for his right arm, and it continued to mimic the poses used in training, as you can see in the video below!