Blog Posts

Dean Blackketter’s Expansion Add-On for Teensy 4.0

Dean Blackketter created an add-on board which makes Teensy 4.0’s bottom-side pads available as a second row of normal pins!

It attaches underneath with castellated holes to solder to Teensy 4.0’s bottom-side pads.

If you’ve wanted a way to plug Teensy 4.0 into a sturdy through-hole socket and have access to all the signals, this looks like a really nice way to gain easy access to those bottom-side pads.

Dean shared this PCB on OSH Park and the Kicad files on Github.  Much more detail is available on Dean’s forum post and conversation which follows.

Lilla MIDI Expander

Sandro Grassia made Lilla, an neat, open source,  polyphonic MIDI expander.

Lilla’s controls features 12 rotary encoders and 8 pushbuttons and includes MIDI in, MIDI thru, and stereo out.  It can read files from and SD card as well as internal memory.

Additional details as well as code for the project can be found on GitHub.

 

Acoustic Levitator

Arvind Singh (forum user vindar) made an amazing acoustic levitator.

An acoustic levitator uses sound waves to levitate small objects, and until a few years ago were expensive to construct using Langevin horns that required tight tolerances and operate at high voltages.  Asier Marzo from Bristol University published a paper demonstrating how an acoustic levitator can be constructed from off the shelf parts and run on low-voltage.

Arvind built a levitator from an Instructible project based on an Arduino Nano, then decided to improve upon it by building one with a Teensy 3.2.  The processing power and memort of the Teensy 3.2 allowed for additional options to be added such as a TFT display and a joystick.

The casing was 3D printed using wood PLA then stained and varnished making for a beautiful device.

Code, schematics, and STL files are available on Git Hub.

RCA 118 “tombstone” MP3 Player

Mike Mitchell (dundakitty of the forum) took an old RCA 118 radio and turned into a very classy looking MP3 player.

The radio was stripped down to it’s chassis, retaining the original tuning dial and the knobs.  A couple of small speakers and a 20-watt stereo amplifier that are both controlled by a Teensy 3.6.

MP3 files of old radio broadcasts were collected and loaded onto a micro SD card.  The Teensy reads the capacitance of the tuner to randomly select a directory and file on the SD card to play.   The Teensy Audio Library was used to add a “hissing” sound between stations for an authentic old-time radio effect.  The project is housed in a beautiful, custom-made cabinet.

 

Larry’s Coffee Roaster

Larry McGovern (elkayem) developed a very cool coffee roaster that can roast up to a half pound of coffee using a custom roasting profile.

This fluid-bed style roaster can run in one of two modes – auto, where the temperature and fan speed are controlled by a settable profile; or manual, where the temperature and fan speed can be controlled in real time.    Temperatures, set value, fan speed, and heater duty cycle measurements are saved to an SD card while roasting as a CSV file for later analysis.

The roaster also has the ability to interface with Artisan Roaster Scope, an open-source software program for coffee roasting that records, analyzes, and controls roast profiles.  While the Teensy 3.5 used in the project collects roast data to the SD card, Artisan includes some nice features to analyze your roast.

There is a great detailed write up on this Git Hub page.  It not only includes code for the project, but schematics, Eagle files, files for the 3D printing of a few parts, and files to laser cut the the case.

Teensyboy by Catskull Electronics

David DeGraw of Catskull Electronics has developed Teensyboy, an awesome little MIDI adapter for a Nintendo Gameboy.

This compact little shield is about the size of thumb drive and uses USB MIDI.  Simply plug it into into a computer and fire up your favorite digital audio workstation (DAW) and you’ll be jamming with your Gameboy before you know it.

There is also a Teensyboy Pro that includes a variety of modes to accommodate Little Sound DJ (LSDJ), Nanoloop and mGB.  It also has convenient mounting holes for installation into a case.

Vague Robots has some tutorial videos on using the Teensyboy Pro with LSDJ

The software is available on catskull’s gitHub repository.  It’s a fork of this Arduinoboy software by trash80.