Alex Lorman had two things: a 2006 4Runner and a desire for year-round posterior comfort. So he picked up some OEM switches. And some commodity seat heaters. And a whole bunch of knowledge along the way!

The project culminated in a custom PCB, primarily as a home for the MOSFETs required to drive 10A per channel to the heaters. And to manage state and the MOSFETs, a Teensy 3.2 was employed.

One interesting aspect of the project was the employment of low-rate PWM to allow the MOSFETs to avalanche while capitalizing on the high resistance of the heated heaters to enable self-regulation. A GitHub repository serves as a clearing house for information and resources related to the product, with two further repos for the PCB and code.

Jigglypuff works in a noisy office, and wanted to avoid the complaints that their built-in laptop mic was garnering during Teams meetings.

Instead of juggling muting in the software itself, they converted a vintage Turner CB desk mic into a digital USB microphone using Teensy 4.0.

After an initial prototype proved unsatisfactory, Jigglypuff switched to the Teensy Audio Shield and a PUI AOM-5024 series electret condenser mic. Unfortunately, the Teensy Audio Shield would not fit inside the Turner, leading to the creation of a custom shield without unwanted features like the mSD slot and line in/out. The final device features push-to-talk with an LED if the mic is active, a pot for mic gain adjustment, a 125Hz high-pass filter, and the all-important ability to present itself as a microphone, not a full-duplex sound card (since it has no output capabilities). Pretty impressive for someone who claims “EE and software is not my primary background.” Learn more and follow the journey in the PJRC forum thread.

Long-time PJRC forum contributor ghostintranslation is back with a new version of the Drone Eurorack module, dubbed Drone 2.0 for its basis on the updated Motherboard 2.0 platform.

The module features four voices with sine and resonant noise oscillators, FM control voltage (CV), individual volts per octave, and a TRS MIDI.

The Motherboard platform underpinning all this was designed to facilitate the creation of new modules, without having to start from scratch every time, and itself features 16 inputs and outputs, MIDI in/out, 10-pin Eurorack power, and Teensy 4.0-based firmware and examples.

Drone 2.0 is available as a PCB/panel kit with SMD components prepopulated. The required BOM, as well as firmware and schematics, can be found in the project’s GitHub repo. Listen to example sounds below!

In addition to our standard form-factor boards, Teensy is available as a member of SparkFun’s MicroMod range of M.2 mix-and-match processors. Maker Evan Rust selected this board to pair with SparkFun’s MicroMod Machine Learning Carrier for a simple yet powerful keyword recognition project.

Using publicly available datasets, Evan uploaded clips of half a dozen keywords to Edge Impulse, along with “noise” samples, and trained a Keras neural network with 92.7% recognition accuracy. Combining the resultant Arduino library generated by Edge Impulse with Teensy’s Audio Library, then downsampling from 44.1KHz to 16KHz in order to match the dataset’s samples, the inference results are displayed on an ILI9341-driven TFT in real time as a bar graph of sorts reflecting the model’s confidence. A detailed walk-through of how to recreate the project can be found on Hackster.

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.