Blog Posts

Electronic String Instrument

Peter Wiessenthaner has created an Electronic String Instrument in collaboration with Thomas Perizonius and Ulf Schaedla.

Peter uses a  Teensy 3.6 and a PJRC library for the PWM control, which allows a great amount of fine adjustment.  There are two pickups on the right and left of the string, allow composition to represent different overtone curves over the speakers. The fast movements of the motors can lead to highly rhythmic patterns. Peter posted about the project as well as uploading a demonstration to his YouTube channel.

Hal9000 Self-Balancing Robot

In his latest robotics project, Youtube-renown maker and engineer James Burton revisits the question of how to design a robot which can successfully balance on a large ball.

This is Burton’s second version of the project which he started in 2015 with the invention of the robot BB-8. In lieu of brushed motors, this new version uses brushless motors and ODrive controllers granting the robot speed, agility, and accuracy. It also includes an MPU6050 inertial measurement unit module as well as a nRF2401 module for radio control, all driven by a Teensy 4.1.

Not only does the new version of the ball-balancing robot perform its task with great ease, but the robot’s appearance has also seen a striking upgrade. This current version is built to resemble Hal 9000 the sinister computer from 2001 A Space Odyssey featuring a glowing red light positioned in the center (it does not, however, address the user as “Dave”). In the hilarious video above Burton describes the making of the project and also demonstrates the robot balancing on an oversized disco ball.

Pierre-Loup’s Replica Minimoog Synthesizer

Paris-based maker and musician Pierre-Loup M. has recreated the iconic 1970s Minimoog synthesizer to stunning detail using a Teensy 4.0 and the Teensy audio library.

In his project released on Hackaday, Pierre-Loup shares all the details behind the manufacturing of this DIY version of the Minimoog including laser cutting the modulation and pitch bend wheels to cutting the body out of a retired walnut dining room table. The keyboard itself is taken from an old Bontempi electric piano.

For those who would like to try their hand at making their own Minimoog, he has released the source code on Github for the Minimoog as well as the Minimoog Mega (versions 1 and 2). In an interview with Hackster, he mentions that his version of the synth “implements the same functions as the real one, plus or minus a few ones.” You can hear the Minimoog in action in a version of popcorn Pierre-Loupe posted to SoundCloud where all sounds are made by the synth aside from the drum effects.

Robot Missions Bowie Brain Kit

If you’re an intermediate maker hoping to take your hands-on robotics skills to the next level but aren’t exactly sure how to get started, the Bowie Brain Kit might be just the thing.

Built by Robot Missions the Bowie Brain Kit comes with everything you’ll need to assemble your own “robot brain” including sensors, motor drivers, coin cell battery, speaker, enclosure and a Teensy 3.6 among other smaller but necessary parts like diodes and resistors. Most importantly, the kit comes with full instructions that will walk you through how to assemble the brain including soldering and attaching components to the board.

In the video below, a couple members of the Robot Missions team perform brain surgery on a weather-sensing environmental robot to show how each of the components work together.

Robot Missions⁠—whose self-declared mission is to build low-cost robotics systems for environmental applications⁠—has, among other interesting projects, deployed rover-style versions of robots that use the Bowie brain to clean up public beaches by sifting sand for trash.

Aiie! Apple //e emulator

Jorj Bauer has made a full-speed handheld Apple //e emulator using a Teensy 3.6. – UPDATE NOW USES TEENSY 4.1

Aiie! is an Apple //e emulator, made by Jorj Bauer using a Teensy 3.6. The Apple //e is a vintage desktop computer that was released by Apple in 1983. It was a popular first home computer for many people and was manufactured and sold for 11 years, making it the longest living computer in Apple’s history. Aiie! is named after a sound effect in the classic 1981 Apple //e game Ali Baba and the Forty Thieves.

Bauer copied the ROM from a vintage Apple //e and has replicated it in three prototypes: one in the original desktop form factor and two scaled down handheld versions using 3″ and 5″ LCD screens. Happily for us, Bauer has documented his work on Aiie! extensively. You can see his code on GitHub along with a readme file full of helpful notes aimed at other people who might want to try making a similar project. You can also check out the informative build logs for the Aiie! Apple //e emulator on the project page, see or follow Bauer’s work on Twitter.

Rotorphon – An Electro-Acoustical Synthesizer

If you’ve ever struggled to learn how to play guitar and thought to yourself, “there must be another way” then you’ll be delighted by this guitar synthesiser project that creator Mike Utz recently shared to the Teensy forum.

Mike Utz, a Swiss sound engineer, has created this clever and unusual synthesizer that at heart is a guitar that actually plays itself. The synth uses a number of mechanical actuators attached to the body of a guitar driven by a Teensy 3.2. By combining analog and digital processes, Utz creates an interesting combination of sounds by way of producing vibrations against the guitar’s body.

Utz’s project, which he’s dubbed the “Rotorphon,” includes DC moving coils, servos, DC motors, and stepper motors that can be controlled using MIDI via USB. Below you can see the Rotorphon in action playing the theme to Knight Rider (a true test of musical excellence) or head over to Youtube to see it perform the theme from Super Mario or Kraftwerk’s Die Roboter. You can see more of Utz’s sound and engineering-focused projects on his website.


ARDOP – HF Radio Modem

Developer Tom Lafleur has created this development board for testing a new HF radio modem called ARDOP (short for Amateur Radio Digital Open Protocol) for use on the Winlink network.

Winlink is a global radio email service that uses radio pathways to communicate in spaces where the internet isn’t available. Winlink is used by Amateur radio operators worldwide, as well as the Red Cross, TSA and many government agencies who use it as an alternative method of relaying information in spaces where the internet can’t reach. The service is developed and maintained by volunteers via the Amateur Radio Safety Foundation.

ARDOP, which can be used on a number of operating systems and devices, is compatible with both HF and VHF radio transmissions. The protocol can operate over a wide range of data rates by automatically adjusting for optimized performance under poor multi-path conditions.

Lafleur’s development board makes use of the full processing power of a Teensy 3.6 as well as the 16 bit ATD and 12 bit DAC. The board features aux, radio frequency control, and can interface with a PC or tablet via serial or Bluetooth 4.2.

Octo-Bouncer Automatic Ping Pong Bot

For years, maker and blogger Tobias Khun carefully considered the question: what would it take to build a robotic ping pong player capable of keeping a ball in motion for hours on end? The result, the Octo-Bouncer, is the perfect mechanical juggler.

The ping pong paddle takes the form of a horizontally-aligned clear acrylic plate which is carefully controlled by four servo motors driven by a Teensy 4.0. In order to determine when it’s time to move the plate (and how including angle and force), the Octo-Bouncer turns to computer vision analysis of a camera feed for a See3CAM_CU135 camera module located beneath the clear plate.

The analysis is performed using openCV running in Unity at a whopping 120 frames per second. The program uses a custom ball detection algorithm and includes data visualization of the ball’s location. Having iterated on the project for over five years, Khun is still making improvements to the programming which he’s open sourced including most recently adding plate tilt visualization, hit position prediction, and analytical tilt control. The project is also a marvel of manufacturing with over 150 CNC-ed parts that and Khun has generously provided the Fusion360 files for on Github.