Blog Posts

Last time we saw The Sketchy Maker on the PJRC blog, it was in the form of a giant 3d-printed LEGO Luke Skywalker, in celebration of Star Wars day. Now they’re back, but have taken a turn to the dark side, with a giant Darth Vader minifigure.

The more sinister effigy follows the same formula as the previous project, with a servo-powered arm, WS2812B-enhanced light saber, and a speaker for sound effects, all driven by our Prop Shield. Just like last time, the models were displayed publicly for the local community to enjoy, and thankfully avoided any dodgy Scottish weather and made it back safely to the shelf after their exhibition.

After four years in development, Guilherme Martins has released Vimana, a multi-track MIDI step sequencer. Vimana is designed to be open and flexible in terms of software and UI.

Vimana features 16 tracks, with a main clock and division/multiplication per track. Step parameters include pitch, velocity, gate, retrigger, chord, inversions and sustain. Play modes range from the expected “forward” to the interesting “pendulum” to the shocking “drunk!”

A built in quantizer features various predefined scales plus the possibility to define custom, and a Euclidean Generator adds complex generative beats. Check out the video below for a walkthrough of its features!

Flok works with big, expensive IBM iSCSI (Internet Small Computer System Interface) boxes, so the thought occurred: what about the opposite extreme with a microcontroller and SD card? This experiment on Teensy and other boards yielded interesting benchmark results.

Usually benchmarks measure performance of 1 subsysten. But iSCSI requires simultaneous performance from networking and storage systems. Even if each can perform well on its own, what matters is how well they perform when used together.

Based on a Teensy 4.1 with Ethernet, the system yields speeds of up to 6MB/s while reading the SD card, significantly faster than other widely used microcontrollers as shown in the results below.

The device can be used as a SAN (Storage Area Network) by a remotely-connected PC via iSCSI, allowing, for example, the booting of a VMWare cluster from a SD card. Of course a microcontroller and SD card aren’t practical for real-world SAN usage. This project is really only useful as an academic exercise and way to benchmark the relative performance of microcontroller platforms when used with a demanding application which requires simultaneous networking and storage performance.

More information can be found on the project’s web page, with source available on GitHub.

Salil Parekh has been using Teensy LC for e-textile projects, but found it difficult to use while testing and debugging due to its small size, which gave birth to the Soft Breakout Board for Teensy LC.

Similar to a regular breakout board, the Soft Breakout Board brings all of the Teensy pins out for easy access, but rather than an FR-4 PCB, is made of denim.

This breakout was then used to develop this touch reactive art piece.

Magnet wire connects the real pins to large snaps in place of vias, which can then easily be connected to with alligator clips during prototyping. Copper tape can be affixed to the snaps for a more robust solution, then removed and rearranged in subsequent projects. See it in action on Salil’s blog.

XForce has created a programmable controller for WS2812B LED strips. The system is based around the Teensy 4.1 and a Nextion display and features remote operation over radio.

The home screen has five shortcuts for favorite effects, which can be combined, looped, and stored on mSD. Strips of up to 4,000 LEDs can be controlled with the current firmware. Learn more in the original thread.

Sometimes the simplest solutions are the best. KD5RXT (Mark)’s “fairly simple” Teensy RV Leveling Helper (TRLH) may not be uncomplicated as a spirit level, it’s a clever solution to a common problem for RV owners.

The helper is placed on RV’s counter to measure whether the surface is level enough. Adjustment info is sent wirelessly to another unit outside, used to adjust the leveling ramps.

Based around a Bosch BMA400 accelerometer, ILI9341 touchscreen display, and a Teensy 4.0, this simple system takes the guesswork out of leveling your RV.

Using vector information from the accelerometer, the pitch and roll angles are then calculated, in turn providing the number of inches that each wheel on the RV (or wheel and hitch on a trailer) needs to be raised or lowered. A built-in LiPo battery with Adafruit PowerBoost 1000 USB charger ensures portability. A new update even allows two units to cooperate inside and outside of the vehicle using nRF24L01 wireless modules. Source, schematics, CAD files and more can be found on the project’s GitHub repo.

Behringer’s 2001 FCB1010 “MIDI Foot Controller” is a curious device. Ten assignable control pedals and expression pedals let you do — well, anything that you can do using MIDI, from controlling instruments, to lighting and effects, to automation.

But what if it could do even more? This was the question the PJRC forum user Expensive Notes asked themselves as they hatched a plan to gut and replace the internals with a Teensy 4.1 and Teensy Audio Adaptor Board.

The project’s forum thread and accompanying videos detail its evolution into a mono synth, drum machine, and sequencer with SD storage. More detail and generously-documented code can be found in the project’s GitHub repository.

DragonSF has created a Web GUI for Teensy 4.1 with a focus on audio projects. The system consists of a Node server (with some HTML/JS/CSS magic) and a Teensy library, which communicate via Ethernet to allow interactions with the GUI to affect firmware on the Teensy board.

As such, the project requires the Ethernet Kit for Teensy 4.1, as well as 8MB PSRAM and our USB Host Cable for MIDI. The web server and library code can be found on GitHub, and an example implementation, TMSidekick2, is also available on GitHub, including source code and schematics.

Marius4560 created a pretty rad project for their Human-Computer Interaction course assignment: a Teensy 4.0-based looping pedal that even provides its own unique ideas for beats!

The Audio Adaptor Board-based project generates random rhythms and drum sounds, plus lets the user record a chord progression to jam along to. An HTML template generator expands options even further. The video below gives a great overview of its usage, and the GitHub repo contains not just source code, but also more detail on the project.

Douglas Engelbart gave “The Mother of All Demos” in 1968, introducing concepts such as the computer mouse, highlighting text, and hyperlinking documents, which profoundly impacted computing.

Less well-remembered, however, was Engelbart’s chording keyset, a five-button keyboard-like device that allows the input of characters when pressed in specific combinations. Russ Nelson wanted to bring awareness to the forgotten device with his entry in the Odd Inputs and Peculiar Peripherals contest.

Consisting of a Teensy 4.1, a custom PCB, and five mechanical key switches, all wrapped up in a custom enclosure housing the five keys, the hardware is actually quite simple. The Teensy’s USB Host capabilities are leveraged to incorporate mouse inputs before passing fused key codes to a PC, expanding the 5 buttons’ 32 combinations (enough for A-Z) to 256 thanks to the three additional buttons on the mouse. Further information, as well as source code and schematics can be found on the project’s Hackaday page.