Blog Posts

ChrisT had an idea for a MIDI pedal board that could send MIDI messages to his laptop while playing guitar, to trigger samples, change effects, and play synth pad chords.

After prototyping in software using HTML and JavaScript, ChrisT built a prototype using plastic multi-purpose compartment organizers that might ordinarily be used for storing hardware of the fastener variety rather than electronics.

In addition to the Teensy 4.1 and the plastic box, the foot pedal controller features ten soft-touch footswitches and a 2.8″ ILI9341 TFT touchscreen. A JSON file is used to configure the GUI and functionality, and copied to the Teensy in mass storage device mode, meaning that changes can be made without having to compile and re-flash the firmware. In the initial prototype, five of the buttons send chords (defined in the JSON file), while the other six are used to adjust settings. See it in action in the video below, and check out the source (including for the HTML version) on GitHub.

MikeSound found two old phones from the 50s and 70s in his parents’ basement. Still in good working order, and visually striking compared to today’s drab black slabs, Mike decided to give them new lives as Microsoft Teams/Zoom-compatible headsets using Teensy 4.0.

In addition to headset functionality via the Teensy Audio Adaptor Board, the phone dialer has been retrofitted to output the corresponding digits as a USB keyboard. The ringer really functions (when an audio signal is detected), and lifting the handset sends the corresponding keyboard macro to to the PC application to answer (or plays the 440Hz dial tone when there is no call).

Replacing the handset similarly ends the call, and of course, there’s a Mute button. Schematics and source are available on GitHub, so you too can surprise and delight your colleagues with a retro re-fit of your favorite old Bakelite or candlestick telephone!

A hybrid piano translates traditional acoustic piano action into MIDI (unlike a purely digital MIDI keyboard), giving pianists the best of both worlds.

Greg Zweigle had long wanted to build his own, and has gotten all 88 keys working, using two Teensy 4.1s and a Kawai grand piano action.

Greg is working on several different architectures in parallel; while the aforementioned uses two Teensy 4.1s to handle all 88 keys, a higher-performance version uses two 4.1s for every eight keys plus two for a pedal unit (i.e. 24 for a complete piano).

The system measures and sends hammer velocity and optionally damper velocity over MIDI and can also output the data to optional Adafruit 2.8″ TFT touch screens. Schematics, firmware, documentation and more can be found in the project’s GitHub repo, and if you want to get really nerdy, Greg has published data from piano and piano action measurements in another repo. Much of the journey is also published on Greg’s YouTube channel, such as the latest progress below.

Benkster had a dream of creating the perfect custom joystick for Elite Dangerous.

The dream was a lengthy one, spanning two years and numerous iterations. The current version is a leviathan 3d-printed affair with two 3-axis joysticks, one 2-axis joystick, a heap of buttons, and a tiny OLED display to tell you what’s going on, all powered by a Teensy 4.0.

But beyond their dream keyboard, Benkster ended up creating a wealth of information of value to anyone looking to create their own custom keyboard – which has now been assembled into a comprehensive guide. Because sometimes it’s not the joystick, but the instructions we make along the way.

Lucian_dusk has created a self-described “functional Teensy 4.1-based breakout board for Eurorack modular synth(s).”

Based around the versatile Cirrus Logic CS42448 audio codec, the board features CV input and multichannel audio I/O, with an auxiliary PCB multiplexing five channels into one analog pin. More detail, including schematics, can be found in the original forum thread.

Madgrizzle’s FloydTheRobot is an ongoing DIY ‘bot project with ever-evolving capabilities, the latest being the addition of two quite versatile-looking Teensy 4.1-powered arms.

The controller has four TI DRV8874 H-bridge motor drivers and four ports for Hiwonder HX-35HM Serial Bus Servos. Two PWM servos control pan/tilt of the robot’s camera, and integrated fan management keeps the servos cool.

See it all in action in the video below, driven by the ROS MoveIt motion planning framework.

Sylvain Van Iniitu has open-sourced their Teensy 4.1-based polyrythmic errorist and stochastic MIDI sequencer, Piccolo meant for generative and process-based music.

Featuring MIDI in and out, tap tempo, 16 channels x 4 layers, and 64 layer memories (save/load as .txt on mSD), the system boasts 1ms precision and unlimited notes per layer and loop duration. Delay, variable delay, transposition, harmonization, modulation and other transformations can be applied to sequences — more than 100 in total.

Source code and schematics are available on GitHub, and over an hour of experimental output during its development can be experienced in the video below.

John Semmens reached out to us to share his Voyager Sailing Drones — a pair of low-cost autonomous ocean-going boats, powered by Teensy 4.1.

The drones are four and six feet in length respectively, constructed of fiberglass over a foam core, similar to a surfboard. The self-trimming sail is controlled via Bluetooth. An Ebyte 433MHz E32 LoRa module provides short-range telemetry and waypoint updates, while a u-blox SAM-M10Q GNSS antenna module provides positioning detail.

An Astronode S+ satellite module handles long-range comms. The Teensy’s onboard mSD card is used for datalogging and debugging after a mission is complete.

While solar charging was originally planned, underclocking the Teensy to 24MHz has allowed almost a full month of operation, making the need for additional charging redundant. Follow the project on its dedicated blog, and see it in action in the video below!

PJRC forum member blackcoffee has created a Thermal Imaging Camera based on Kris Kasprzak’s original Teensy 3.2-based project, using the same AMG8833 infrared array sensor, but updated to use Teensy 4.0.

The unique enclosure holds a homemade PCB, in addition to the sensor, batteries and LCD display. STL files and Gerbers can be found on Thingiverse, and a demonstration of the device in action can be seen in the video below.

Ted Fried of MicroCore Labs picked up a 1975 HP 1600A/1607A logic analyzer set over the weekend, his first instinct was to throw a Teensy at it!

The Teensy 4.1 was just the thing to provide 32 data signals and two clock outputs to the HP1600A logic analyzer, which provided some stimulus to the device and tinkerer alike, but then Ted discovered the “MAP” function! This allowed him to write to a 64×64 pixel map, the results of which can be seen below. This evolved into full-on monochrome BMP display, including a utility to convert the files to the MAP format, as seen in the first image. We can’t wait to see what Ted does with it next, and we’re guessing we’ll find out what that is on his blog.

Ted has is someone you’ll find all over our blog and forums with many interesting projects.