Blog Posts

Musical String Winder

Some things are more complicated than they appear at first glance. Take, for example, the metal strings of a musical instrument.

How are these made? Forum user jpk generously shared the results of the two years he spent building his own metal musical string winder.

To accomplish the project, jpk used a Teensy 3.5 to handle button input, display output, and calculations and a Teensy 3.6 that handles motor movements, both set into custom PCBs. The machine can also be used to spool wire. Jpk has made his source code for the project available on Github as well as a timing library and a debouncing library he developed for use with the project. Below is a photo of a completed wound wire that uses copper and aluminum to produce a string that is 0.7mm in diameter.

Knitted Keyboard

MIT Media Lab have developed the new and improved Knitted Keyboard II using electrically conductive, capacitive and piezoresistive fabrics and fibers.

The Knitted Keyboard II, from Irmandy Wicaksono and team, is a multi-modal, soft and stretchable e-textile musical interface. It responds to touch, including keystrokes, pressure, squeezing and pulling, and continuous proximity, such as hovering and waving. This means that you can play it in a range of ways: like a keyboard, a theremin or as something that is a mixture of the two. You can even wear it like a scarf.

MIT’s Knitted Keyboard II runs on a Teensy 4.0 and uses five MPR121 proximity/touch controllers. It uses MIDI and can therefore sound like any software instrument you have access to, making it incredibly versatile.

Check out Hackaday’s coverage of the Knitted Keyboard II or read the MIT project overview for more detail on this project.

Teensy TV: JPGs on an Analog TV

Hardware hacker Hypothete has hooked up a Teensy 4.0 to an analog TV, to display JPG and PNG images in the NTSC video format.

This Teensy is taking in uploaded jpgs and outputting an analog TV signal?! I'm interested! … Thanks for bringing in and sharing your project @hypothete! More info at

Posted by Ctrl-H on Wednesday, February 5, 2020

The cozy hackerspace Ctrl-H in Portland runs an event twice a month called DorkbotPDX, which is where Hypothete came to show off Teensy TV, their super cool analog TV hack. The Teensy TV is made up of two parts: a Teensy 4.0 running an Arduino sketch, and a Node.js server sending data to the Teensy.

The whole project has been written up over on Hypothete’s GitHub, including wiring instructions, code and reference links if you want to dive further into the world of analog video hacking.


Sky Vane – Acoustic Art Installation

The Sky Vane is a reactive sound installation that generates a stunning ethereal soundtrack based on readings from atmospheric sensors.

The sounds you can hear in the tweets below are created from readings taken from a simple set of sensitive weather sensors (temperature, pressure, humidity, and light). These readings are dynamically assembled, manipulated, and evolved in real time using both a Raspberry Pi and Teensy microcontroller.

The Sky Vane is designed by pyka, a team that designs interactive sound tools and makes engaging experiences. Check out more projects from pyka on their website, their Twitter account or over on Instagram.

Digital Saxophone/Clarinet

The Vindor ES is an electronic saxophone / clarinet from Vindor Music with has a sophisticated and easy-to-play design.

The Vindor ES is a USB MIDI controller with a built-in synthesizer, speaker, headphone jack, plus a 1/4″ jack output for an amplifier or guitar pedal. Developed for the educational market, it comes with online and mobile education software.

The digital saxophone is controlled with a Teensy 3.1. Vindor used SPI (for the SD card), TSI (touch sensors for individual buttons) and DAC (for the audio generation, including the fabulous audio library). There is also a Freescale pressure sensor to measure breath and an amplifier/speaker.

Find more information and check out more feature demos over on the  Vindor Music website.




YaRC Vehicle Series

Welters Hackz has published details of a series of radio controlled vehicles, the YaRC 1 and 2 and the latest addition, YaRC mark 3.

The acronym YaRC stands for Yet another RC vehicle. The first YaRC was made out of Lego bricks and used a Teensy 3.2, a Raspberry Pi and various motors. The second YaRC added in a camera for video transmission and a WiFi dongle to help with communication. The third YaRC kept the software of the previous two projects but upgraded almost all of the hardware, including a chassis upgrade and a newer Raspberry Pi.

Welters Hackz has done a great job of documenting the evolution of this RC project, with build logs, schematic diagrams, component lists, useful explanations and links to helpful code repositories. Check out the YaRC project pages for the YaRC 1 and 2 and YaRC mark 3 on

Convolution Software Defined Radio

PJRC forum user DD4WH made the Teensy Convolution SDR, a software defined radio for long wave, medium wave, short wave and wide band FM stereo.

Software defined radio (SDR) is a radio communication system in which the traditional hardware systems — such as mixers, amplifiers and filters — are replaced with software.

DD4WH used a Teensy 3.6, a PJRC audio board, a quadrature sampling detector (QSD), an oscillator capable of being tuned by I2C, three encoders and an antenna to make the Teensy Convolution SDR. DD4WH chose to do the main filtering and demodulation in the frequency domain using a fast convolution approach, enabling much steeper filters than the usual phasing approach.

Detailed specifications and a project guide for the Teensy Convolution SDR project have been published on DD4WH’s GitHub. The original forum post about the project is also really worth checking out, with helpful comments about sourcing components and troubleshooting the code.