Blog Posts

MIDI Bass Guitar

We see a lot of Teensy projects that bring the noise, but how many bring the funk? While it’s hard to say for certain without audio proof to back it up, Lokki’s MIDI bass controller certainly looks capable of putting some serious stank on it.

This unique Teensy 3.6-based instrument gives the approximate appearance of a four-string bass guitar, but is in fact a (left-handed!) MIDI controller! In a manner similar to the Otamatone, long, thin, soft membrane potentiometers are used in place of strings for pitch, and a further four force-sensitive resistors enable additional keyboard expression (or…guitar expression as the case may be!). A joystick enables whammy-like pitch bending, and an accelerometer in the neck enables ancillary gestural control.

The Teensy’s USB host capabilities allow control of up to seven USB MIDI devices, as well as the embedding of a Keith McMillen K-Board mini keyboard controller for triggering samples. We’d love to hear some of the funk this thing may bring, but for now we can just look at the pictures as we put on our best stank faces and imagine.

Parallel Battery Charger

What do you do when you’ve got a pile of quality Panasonic NiMH batteries and power-hungry robots that need high-capacity charged packs?

If you’re the folks over at PDX Hackerspace, a community-focused collective in Portland, Oregon, you assemble them into bot-ready packs and design a Teensy-powered board to charge them!

Teensy monitors the ambient and internal battery temperatures in order to prevent over-charging, and appears to incorporate a piezo speaker to indicate charge completion or problems.

MDV microSynth

Marco De Vivo demonstrates (video) with his MDV microSynth even a fairly simple Teensy-based synth leveraging the Teensy Audio Library can produce excellent results!

In this project he creates a powerful instrument from a Teensy and Audio Adapter, plus an LCD display, potentiometer, a 5-Pin DIN MIDI jack, and a few buttons — all on a breadboard!

We weren’t able to find a ton of info beyond the video below, which gives a great demonstration of its capabilities. The synth is monophonic with four oscillators, low and high-pass filters, ADSR envelope control, and various effects including stereo delay, portamento, and morphing via modulation wheel.

Horizon OBD2 CAN Programmable Module

Sebastian Yousef of SIGMAGAMMALabs has created an Arduino-compatible OBD-II device in the form of the Teensy-based Horizon OBD-Interface Module.

Hidden under the dash in most modern cars is a secret portal to a wealth of data and diagnostics. Once purely the domain of repair shops, OBD-II dongles are now available inexpensively with Bluetooth and other secondary connections to allow them to easily connect to other devices for analysis.

The module can be programmed and flashed over USB in order to extend the capabilities of the example firmware, with the same interface providing access to ODB-II data such as RPM, ETH, LOAD and SPEED. Built-in Bluetooth and an optional BLE radio further facilitate data collection, plus the Teensy’s microSD card slot can be used for onboard data logging.

More information about the project can be found on the SIGMAGAMMALabs web site.

Motorized Table Saw Fence

KrisKasprzak is fairly prodigious in terms of Teensy-based output, so it was no surprise to see his Teensy-based motorized table saw fence project, complete with detailed pictures, video, and source code!

The CNC motorized system is compatible with Craftsman, Dewalt, and Rigid table saws, and features two NEMA-17 stepper motors with A4899 drivers, a 2.8″ LCD, and a Teensy 3.2. Simply enter your desired fence location, and the steppers do the rest.

A simple “garage-made” PCB ties it all together, though it could just as easily be breadboarded. The video below shows how to make your own, with source available on GitHub.

Teensy FX Effects Unit

Matt Venn, famous for Tiny Tapeout, wanted a Teensy 4-powered effects unit in the Pocket Operator-style form factor, and called it Teensy FX.

Unlike a typical Teenage Engineering Pocket Operator, the Teensy FX lacks an LCD screen, instead indicating everything via LEDs (e.g. brightness to represent parameter value). Additionally, whereas POs typically feature a grid of buttons and a couple of knobs, the FX features 12 knobs, which better lend themselves to tweaking effects levels.

The design is based off of the similarly Pocket Operator-esque Teensy Beats Shield, and uses the same SGTL5000 low-power stereo codec. The FX’s patch was created using the Audio System Design Tool, and features filtered reverb, ping-pong filtered delay as a noise source, and more. The device also features PO sync to chain it with other Pocket Operators, and automation on each knob. Source, schematic, gerbers and more can be found on the project’s GitHub page, and an accompanying video series can be enjoyed below.

Plotbot

Sei had two things: a bare wall in their apartment, and a tendency to (their words!) “waste money on useless electronics” — and thus Plotbot was born.

Powered by a Teensy 3.1 and a pair of Nema 17 stepper motors with SilentStepStick TMC2209 drivers, the system uses an extruded aluminum frame and arms in conjunction with a system of pulleys to drag a pen over a large sheet of paper, creating the desired drawing.

More information can be found on the project’s Hackaday page and GitHub repo, with a quick demonstration in the video below.

POCSAG Pager Transmitter

EverestX on SOLDIERX yearned for the simpler times of the beeper, and decided to bring them back at a personal scale with a custom Teensy-powered POCSAG pager transmitter.

In the days before everyone carried boring black slabs of always-on hyperconnectivity around in their pockets all day, being reachable away from your desk or home was actually fairly unusual — the domain of doctors, network admins, and … certain other high-income individuals. But with a growing desire among many to disconnect and simplify, the former status symbol of wearing a pager might today appeal as a minimalist messaging solution.

In addition to the Teensy LC and custom PCB, the system incorporates an RFM23BP ISM radio transceiver and HC-05 Bluetooth module. Adopting the Featherwing format resulted in some tight tolerances, but is great for prototyping, and results in a compact build that can be powered by a LiPo battery and charged via USB. EverestX didn’t even have to write any code thanks to the pocsag Arduino library by on1arf on GitHub. Read more about the project’s background, philosophy, and build notes on SOLDIERX.

Commander Keen Game Emulator

Ryzee119 demonstrates the Teensy 4.1’s superior performance with a port of the Commander Keen “Commander Keen in Goodbye Galaxy!” series!

Perhaps best known for first-person shooters like Wolfenstein, Doom, and Quake, id Software’s Commander Keen, the side-scrolling adventure based on their Super Mario Brothers 3 clone for PC, was also an incredible shareware success.

Ryzee119 used the Omnispeak C clone for Windows and Linux as the basis for his Teensy emulator. Requiring just a 64Mbit of PSRAM and an ILI9341 TFT LCD Display, OmnispeakT4 supports save games via SD, Xbox 360 controller input via USB, and with an optional YM3812 OPL2 FM-synthesizer board, genuine OPL AdLin audio synthesis too!

Wiring and compilation details for OmnispeakT4 are available on GitHub, and a video of it in action (complete with sound) can be found on Imgur.

DIY Polyphonic Synth

Florian Loretan bought an old Bontempi keyboard, but it stopped working. Instead of consigning it to the scrap heap, he ended up on a journey to create a custom polyphonic Teensy-based synth, with the only remaining part of the original keyboard being the keys and matrix.

In addition to the Teensy 3.1, an Audio Adaptor Board is used, though not in the typical stacked orientation. Multiplexers handle the keyboard matrix and the custom potentiometer-based interface. More detail on the electronics can be found in a separate video, as can specifics on building the case, and a demo of everything together can be seen below. The source code, which is still a work in progress, can be found on GitHub.