MAD 1.1 Eurorack Module

With over ten thousand Eurorack modules already available in the world, you’d want to be MAD to create a whole new suite of them.

But Michele Perla is just our type of bonkers, and has created a set of Modular Audio Devices that work together as a bridge between analog synths, MIDI keyboards, PCs, and audio interfaces.

The Teensy 3.6-powered CORE module features USB communication with a host PC, 5-pin DIN MIDI in and out jacks, eight CV outs, 8 gate outs, one clock in and one clock out, and a TFT display with four potentiometers for configuration. The “lite” version features a Teensy 3.2.

The CTRL module connects to the CORE via I2C, and adds up to 24 analog sensors, buttons and LEDs, with three address bit jumpers allowing up to eight CTRL modules to be used together. The intuitively-named CODEC module adds an AK4558 CODEC featuring stereo inputs and outputs, as well as a headphone jack, and aux in/out connectors. VCO, VCF, and VCA modules flesh out the line completely.

A demonstration of the CORE prototype can be found in the video below, with more information available on Hackaday, Facebook, and Instagram.

Minimalist USB Host Shield

While the Teensy 4.1 includes a 5-pin USB host header, the smaller 4.0 board, which intrinsically supports the same USB host functionality, exposes bottom-side pads to do so.

The Teensy 4.0 also foregoes the current-limiting circuitry that allows the safe hot-swapping of USB devices. Enter the Teensy 4.0 Minimalist USB Host Shield, the creation of Dave Madison aka Parts Not Included.

The Minimalist USB Host Shield (hereon: MUHS) adds a soft-start current limiter, allowing the host port to slowly ramp up current and handle small surges. It also features ESD protection, a power-conditioning LC filter, and a 500 mA polyfuse to protect the attached Teensy board.

Using standard headers and 12mm pogo pins, all required pads can be connected without any soldering, and a second set of headers enables the resultant stack to be used for breadboarding. Two M3 holes facilitate case mounting of the unified USB unit. KiCAD files, Gerbers, and the complete BOM can be found in the MUHS GitHub repo, and our own USB Host Library is all you need to interface with any connected devices!

AMC8 – Automated MIDI Controller

While nowadays it’s possible to carry an entire studio in your pocket thanks to smartphone apps like FL Studio Mobile and Cubasis, not long ago the idea of computerizing analog studios was still a relatively new and expensive proposition.

King among such solutions was Digidesign’s Pro Tools — a hardware/software hybrid that cost thousands or even tens of thousands of dollars, yet quickly established itself as the industry standard. As Digidesign opened their software platform to other hardware vendors, the Human User Interface (HUI) was developed in order to facilitate communication with 3rd-party control surfaces. Rather than scoring an old Procontrol off of eBay, PJRC forum member rotabox took the ambitious path of creating their own HUI-compatible automated MIDI controller, powered by dual Teensy 3.6s.

The custom control surface features eight motorized faders and OLED displays, a total of 31 buttons, and a custom PCB and enclosure to tie them all together. The video below demonstrates the controller being used with Pro Tools — somehow it’s still just as cool watching those faders fly today!

Voice Recording Phone

Sometimes projects just need a little help from the community to get over the finish line. Forum user letNic posted to our Audio Projects category asking how to monitor a user’s voice while recording it from the microphone, for a more authentic and intuitive “phone” experience.

Veteran forum user oddson jumped in with some suggestions, which worked great and allowed letNic to complete their project. We in turn thought it looked very impressive and worthy of featuring on our blog, hence the post that you are currently reading! So there we have it: another Teensy forums success story! Maybe yours will be the next we feature — send us a tip via the Blog Project Submission category!

Modular Datalogger System

Sophisticated, mature home automation systems like Home Assistant allow us to easily set up and monitor sensors around our houses without writing code or developing custom hardware. But where’s the fun in that!?

We think these are the types of thoughts Teensy forum user Fenichel may have been having when he decided to create his own data logging system from scratch, and deploy it around his house in various ways.

The system consists of multiple Teensy 3.5 sensor stations, each based on the same design, though evolving as requirements and applications develop over time. Data is logged to the Teensy’s onboard mSD card, or sent to a Teensy-based base station over XBee. Real-time clocks on the stations’ custom PCBs help keep things in sync.

Bespoke Windows software provides detailed reporting on the collected data, as well as a board manager for configuring the stations. The project is extensively documented in a 46-page user manual, and schematics can be found on the author’s web site.

Teensy 3.2 End Of Life

With great sadness, we’re discontinuing Teensy 3.2.

Teensy 4.0 and 4.1 will continue.  We’re able to get the new 600 MHz chips in sufficient quantity.

But the sad reality is we simply can’t get enough of the old 72 MHz chips.  The ongoing problems with old chip supply has become a huge distraction which is impeding progress on Teensy 4.x development.

Teensy LC, 3.5, 3.6 were discontinued earlier this year.  When the small stock we have remaining for Teensy 3.2 runs out, it too will be gone.