Blog Posts

LED Audio Meter

Nicolas Toussaint has made a two channel audio meter using a Teensy 3.1, a PJRC audio adapter and two strips of NeoPixel strips from Adafruit.

An audio meter is an essential device in music production, displaying a visual representation of audio signal level. Toussaint has made DIY audio equipment using the Teensy before, and this time he wanted to try making an LED audio meter using a combination of the StereoPeakMeter example in the Teensy audio library with the FastLED library by Dan Garcia.

Toussaint’s helpful project post on the PJRC forum has a components list, his code, projects images and some great bonus information in a follow up comment from Rob Soles, the person behind the AudioPeak object.


Retrofitted Rodgers 32B Organ

John Kinkennon has retrofitted a classic Rodgers 32B organ using a Teensy 3.6 and custom hardware console.

John Kinkennon retrofits old organ consoles with new hardware, allowing them to be used with virtual pipe organ software such as Hauptwerk, Miditzer, or JOrgan. He used a Teensy 3.6 to retrofit a classic Rodgers 32B console, a process involving building custom hardware for the audio encoder, including input boards for pedals, stop tabs and pistons.

Kinkennon’s Rodgers 32B retrofit uses the Teensy 3.6 and plenty of chained 74HC165N shift registers. It has eight analog inputs plus eight GPIO open collector outputs which Kinkennon uses to control solid state relays that turn on audio power.

Kinkennon has helpfully provided code, schematics and other useful information for a number of his projects on his website. You can also find details about another one of his Teensy organ projects, a MIDI message receiver, on the PJRC forum.

Bionic Arm Exoskeleton using Pneumatic Muscles

James Hobson, better known as The Hacksmith on YouTube, has created a Bionic Arm Exoskeleton that features a Teensy 3.5 at the heart of its 86-component controller board. It is a fully functioning pneumatic steel arm based on the “nanosuit” from the first-person shooter Crysis.

In Crysis, the nano-muscle suits are worn by soldiers to increase their physical strength, speed, agility, and ability to defend themselves. In a video posted to his channel, Hobson and team walk us through the process of designing one part of the suit, a bionic arm, as a demonstration of the process needed for creating a full-body suit.

In a post on, Hobson further describes the research that went into the project including examining existing Pneumatic Artificial Muscle (PAM) systems that have existed since the 50s and comparisons to human musculature systems. Hobson also shares the schematic for the circuit for those who are curious to try their hand at the project.

Hobsons other projects include light sabers, the thermal vision helmet from Predator, and Wolverine claws. If you’ve been wanting to take your cosplay to the next level, his channel is worth checking out!

Sound Generation Board

This audio utility board was designed by Arthur Sobel to facilitate the construction of simple audio devices, and is showcased on on

On this board you will find a footprint for the Teensy 3.2 , a single channel PAM8302M speaker amp, MicroSD breakout board, and connectors for keyboard, switches and pots. It’s based on the NXP ARM Cortex M4 MK20DX256VLH7, which has AnalogIO with one DAC pin. It runs at 72Mhz, using a modified  MPR121 test library.

Waveonoi LED Wall Art Installation

The Waveonoi is a light installation, first featured in the Amsterdam Light Festival as part of a larger piece called From Twente with Love.

The project was a collaboration between six students (Edo de Wolf, Jorik Ordelmans, Han de Jong, Lubo Andreev, Wouter Deenik and Emiel Harmsen) from the DesignLab at the University of Twente, as well as the Twentse Ambassade and artist Randy van Lingen.

Initially using eight panels of LEDs and a Teensy 3.6, the piece used a Voronoi pattern to depict a wave rising up from the canal. Visitors could touch the inside of the wave, triggering a beam of “love” that traveled through the wave to sculptures behind, which blew kisses to the boats on the canal. Emil and Wouter have written about their contributions.

One of the panels was upgraded by Emil with a Teensy 4.0 which increased its frame rate from 40 FPS to 140 FPS. The Voronoi pattern is created by 1761 LEDs supported by the OctoWS2811 LED library.

You can also check out this post by Paul from PJRC on the Teensy Forums for more details. Video below.

Digital HD Radio

This Digital HD Radio is a sleek AM/FM radio from PJRC forum user roomtek that runs both HD Radio and RDS (Radio Data System) protocols.

While using the Digital HD Radio, the IPS display shows album art and station logos. It allows for stereo recording and digital audio over USB connection, with a PCM5122 DAC, Teensy 3.6 and inbuilt alarm clock. On the forum post linked above, roomtek shares current and planned features of the radio, along with technical details and the the below board layout.

SchmickBike Motorcycle Monitoring System

SchmickBike is a 3-part motorcycle monitoring system posted by forum user thebigg consisting of a controller, a display, and an app that allow the user to observe real-time data relevant to their ride.

SchmickBike’s 3D-printed controller houses a custom PCB, CANbus transceiver, GPS and Bluetooth modules, power management, and connectors.  The connectors extend to external sensors including an IMU, ultrasonic distance sensors capable of measuring the suspension compression, and a tire temperature monitor. It connects to the bike’s CANbus, fuel injectors and power.

The controller also connects to a 5″ LCD display in a weather resistant enclosure which can be mounted to the handlebars. The automatically-dimming display (determined by an embedded ambient light sensor) has twenty different screens full of useful data including real-time fuel consumption calculators, GPS and sensor results, as well as setup and configuration screens. It has an ambient temperature sensor and configurable status RGB LED alongside options for user inputs such as a handlebar-mounted joystick or buttons.

Driving both display and controller is a Teensy 3.5. According to the creator, the code currently occupies just under 50% of the available flash even with all options enabled.

Thebigg has even created an optional Android app capable of receiving a continuous stream of data from the controller via Bluetooth. The app not only displays the data but uploads it to the cloud so you can keep a record of your data from every ride. It can even transmit portions of text messages to the controller so the driver can decide whether or not it’s time to pull over. Useful stuff!

Amiga Emulator on Teensy 4.1

Less than a week after the release of the Teensy 4.1, developer Jean-Marc Harvengt used it to create a miniature Amiga Emulator running at full speed.

For control input, Jean-Marc created a simple keypad made up of a selection of buttons and a joystick attached to a circuit board. In the video below, you can see Jean-Marc play a variety of classic games from Gauntlet to Xenon using an attached ILI9341 TFT 2.8″ display.

The games are loaded on to the Teensy’s onboard microSD card and accessed via a file list. A recent development which Jean-Marc posted to Github provides HDD support and improved sound.

The Amiga family of personal computers, introduced in the mid-80s, provided a leap in graphics and sound capabilities over previous 8-bit systems. Jean-Marc’s Amiga Emulator is a UAE, or an emulator which allows users to emulate Amiga systems. The “U” in UAE stands for “Unix” but was also jokingly said to stand for  “unusable” in its early development years due to the system’s inability to boot. Jean-Marc’s emulator, on the other hand, is delightfully usable and, for those who are keen to try, Marc has provided his source code and instructions.