Newton USB Keyboard Adapter

Fans of classic Apple keyboards rejoice! Jim Lombardo shared to our forum his recipe for creating a custom USB adapter that allows older keyboard models that use an 8-pin DIN input to serve as modern USB keyboards.

Jim took on the project when he found himself needing a keyboard for a custom Raspberry Pi computer he assembled. He found the perfect mini keyboard for his mini computera 10″ Apple Newton keyboardon hand in his spare parts bin but to his surprise found that no USB adapter already existed for the Newton’s 8-pin DIN F port. Naturally, he took it upon himself to engineer one.

To remap the serial data to USB, Jim uses a Teensy 2.0, a hacked 8-pin mini-DIN M/F or F/F cable to connect to the keyboard, and a USB A to mini B cable to connect the Teensy to the computer. On the software end, Jim created a nice and tidy library which translates the keyboard’s key scan code into ASCII.

As Jim mentions in his blog, the Newton keyboard was originally designed for use with the Newton PDA (Personal Digital Assistant) system which Apple produced in the late 80s and early 90s. While the system was a flop due to high cost and low performance, it did pave the way for Apple’s later multi-touch device successes like the iPhone and the iPad.

Photo by Blake Patterson from Alexandria, VA, USA – Newton and iPhone: ARM and ARM, CC BY 2.0,


Burning Man Art – 6400 LED Solar Tricycle

Burning Man art car builder Loren Carpenter has taken Teensy’s ability to drive LEDs to the next level with a solar-powered installation built around a tricycle that uses a Teensy 3.6 to drive 6,400 RGB WS2812 LEDs.

The 32 channel system is capable of outputting ~1.3 million RGB pixels per second, achieving over a 200 Hz frame rate for smooth animations. In the forum post linked above, Carpenter dives deep into the technical details, including his source code for those who want to try it out themselves.

The project was first built around a golf cart but the latest build uses a tricycle as a frame with a control box directly underneath that includes relays and battery chargers. Here you can see a video of Loren’s creation in action from a night on the playa at Burning Man in 2015.


Easy MIDI Chord Controller

French musician and composer Emmanuelle Presselin developed a sound controller which generates MIDI chords on touch.

Presselin, who doesn’t play keyboard but often begins his compositions by layering chords together, was looking for an easy solution to generate complete chords. Presselin explains in his post to our forum where he also kindly shares his source code, that each note on the controller is capable of producing twenty chord structures with four basses per note. Additional knobs can be used to adjust volume, invert chords, change velocity, control octaves, and add arpeggios. Combining these along with additional features like style banks and custom chords, the controller offers numerous avenues for musical experimentation with just a few simple presses of the keys.

Presselin used pressure sensitive conductive sheets (a material known as Velostat or Linqstat) to create force sensitive resistors (FSRs) that act as triggers for MIDI chords based on measuring applied pressure. Velostat is often used as a packaging material to protect electronics which are susceptible to damage from electrostatic charge but can also be used in wearables or to make custom sensors as seen in this project. Presselin’s controller uses the material to make 168 discreet FSRs, allowing the user to create a wide range of sounds and even generate complete compositions by combining tools like Ableton Live as demonstrated in the video below.


Draw Bar Organ Module

Vintage effects and musitronics repair specialist Richard Lingenberg has created an open source 9 draw bar MIDI/ USB Host keyboard organ module that he shared to our forum.

The organ uses one Teensy 4.0 to drive the Rev. D audio board and one Teensy 3.6 to drive a ILI9341 touch display. The organ makes use of the Teensy’s audio libraries and built-in SD card reader to store up to 105 patches including 22 preset patches. It also includes settings for Attack, Hold, Decay, Sustain and Release.

A draw bar, as it usually appears on a traditional hammond organ, is a metal slider that controls the volume of a particular sound component such as a harmonic or fundamental of the note being played as it slides in and out. When the bar is fully pressed inward, the sound output of that component is zero or completely silenced. This allows the operator to selectively mix the sounds produced by the organ’s tonewheel. If you’re curious to hear what the organ sounds like, you can listen to a demo Richard put together on SoundCloud.

Audio Codec Breakout Board

Teensy forum user kxmx_kaugummi has made a multi-channel audio codec breakout board for their modular synth set up using the Teensy and a Cirrus Logic CS42448.

An audio codec is a device that translates an analog audio signal into digital signals and turns digital back into analog. This gives us both an analog-to-digital converter (ADC) and digital-to-analog converter (DAC) that run off the same clock signal. The Cirrus Logic CS42448 is a popular 6 input, 8 output audio codec supported by the Teensy Audio library.

Teensy forum user kxmx_kaugummi used the Cirrus Logic CS42448 with a Teensy, breaking out the 6 input and 8 output differential audio signal pairs of the CS42448 and routing the digital signaling (TDM) and control (I2C) to the Teensy. This gives lots of audio channel in and out of Teensy, in a smaller, more modular form factor than other CS42448 boards.

You can find the schematic and bill of materials for both the Teensy 3.5/6 and the Teensy 4.0 over on kxmx_kaugummi’s EasyEDA page.

1930s Teletype with USB Interface

Hardware hacker Trammell Hudson used a Teensy and a handful of components to control a mechanical 1930s Teletype machine.

Model 15 teletype operation

Teletype machines from the 1930s are beautiful mechanical objects. Trammell Hudson was able to control one from his laptop using a Teensy and a handful of electronics components on a protoboard small enough to fit inside an Altoids tin.

Hudson has published a blog post detailing his approach and also a Flickr gallery of the project, including many close up images of the beautiful vintage mechanical Teletype machine and videos of it in action. Hudson has also published the schematics and source code for this project on his website.

This project was completed by Hudson while he was a member of NYC resistor, a hacker collective in Brooklyn, New York. The collective was founded in 2008, making NYC Resistor one of the first hackerspaces founded in the USA. The space is open to the public for workshops and weekly open days if you’re in New York and want to check it out.

Images by Trammell Hudson, shared under the CC-BY license.

Harmonicade: Arcade Button Synth

The Harmonicade is an impressive synth made of over 200 arcade buttons, a Teensy 3.6 and a lot of 3D printing.

The person behind KOOP Instruments wanted to learn to make music, but the traditional piano layout didn’t suit him. So, he started making his own range of musical midi devices, which are now all immaculately written up and shared over on the KOOP Instruments site.

The Harmonicade is a multi-channel MIDI keyboard using arcade push-buttons in a Wicki-Hayden style button layout, a musical keyboard layout based on hexagons. It uses over 200 arcade buttons feeding into a single Teensy 3.6 via two sets of DB25 connectors – an ingenious solution to his wiring problem!

As with all the other KOOP Instruments releases, the Harmonicade has been impeccably documented, including step-by-step build instructions with detailed wiring instructions, 3D modelling files, and helpfully commented code.

You can also read a write up of the Harmonicade on the Hackaday blog.