Gone are the days of needing a mainframe or even desktop computer to run your Lisp code, now you can use a handheld device complete with display and full keyboard and powered by a Teensy 4.1.

Unless you’re the lucky owner of one of those Cray-1 supercomputers that both runs Lisp and has built-in seating, you’re likely going to have to give in and get up to find the closest Lisp machine. Unsatisfied with this status quo, maker and microcontroller enthusiast Hartmut Grawe envisioned a new solution in the form of the LispDeck, a Teensy 4.1-based handheld cyberdeck that runs the microcontroller-optimized uLisp programming language. An RA8875-driven touchscreen and USB mini keyboard enable comfortable Lisp editing, with files saved and loaded from the Teensy’s SD card. A smaller 160×128 TFT screen and rotary encoder add “Lispy Little Helper” functionality to the editor, providing convenient access to the full list of uLisp symbols. RFM69 and ESP8266 modules provide LoRa and Wi-Fi respectively, with both programmatically accessible from the editor.

More detail can be found on Hackaday, with firmware and STL files on GitHub.

Mark “The Electronic Engineer” Donners, is back with a digital vocoder that make you sounds like a Cylon from Battlestar Galactica.

After presenting this impressive spectrum analyzer in his video, Mark reveals that he’s actually taking things in the opposite direction: using analyzed frequencies to create sound! Mark shows viewers how to wire up a simple circuit based on the Teensy 4.0 with Audio Shield, plus a few potentiometers, a button, and a 3.5mm TRS audio jack.

This is used to analyze audio data, and output a parallel signal based on that data, in the form of a vocoder, reminiscent of the 1978 Battlestar Galactica series’ Cylon characters. For completeness, Mark also added the sound associated with the Cylon’s Larson scanners.

The Teensy Audio Library is used, in simple terms, to rip apart the signal and build it up again.

More info, including a complete BOM, can be found on the episode page with downloads including the sketch at schematic available on the episode resource page.

You can follow along with the build and hear the project in action in this video.

We’ve perviously featured Mark’s work with a Spectrum Analyzer and VU Meter project.

Researchers Jéssica Cristina Tironi, Anita Fernandes, Renata Coelho Borges, Luis Augusto Silva, and Wemerson Delcio Parreira have developed a prototype self-stabilizing pen that counters hand tremors in Parkinson’s patients.

The system uses an Analog Devices ADXL345 accelerometer to monitor tremor oscillations, a Teensy 4.1 to analyze them in real time, and a vibration motor to dynamically counteract their effects. As seen in other tremor mitigation projects, a Kalman filter was employed to transform complicated data into useful outputs. While the initial prototype has provided encouraging outcomes, the researchers are considering adding additional sensors and further performance enhancements in a subsequent version. Dive into the original paper for more information.

Yang Zhang, Robert Xiao, and Chris Harrison have used a Teensy 3.2 to explore Electrical Impedance Tomography (EIT) sensing schemes.

Expanding on research from a gesture-sensing smartwatch, the system can select between traditional two-pole sensing, where a single pair of electrodes act as emitter and receiver, or four-pole, where an AC signal is used to measure voltage between two pairs. Eight, 16, and 32-electrode configurations of each allow extensive experimentation to explore advantages and drawbacks to each.

A custom PCB houses the Teensy 3.2, along with a voltage-controlled current source (VCCS), direct digital synthesizer (DDS) and ADC preamp, plus multiplexers to allow dynamic electrode schema selection. Find out more on Chris’s web site, check out the PCB on GitHub, read the research paper, or watch the video below.

LED and pixel art have become ubiquitous, but have you ever thought about how difficult something like this would have been to achieve in 1973? Andrew Seawright has, as a necessity of recreating his father James Seawright’s Network IV sculpture.

The original was installed in Concourse B of the Seattle-Tacoma Airport, and used 1024 GE R6A neon glow lamps. It was controlled by a Data General Nova 1210 minicomputer and featured three Moog-style analog synthesizers. Instead of recreating the piece with modern code, Andrew emulated the Nova on a Raspberry Pi 4B, then ran the original code, extracted from paper tape. A Teensy 4.0 using the OctoWS2811 library controls LEDs in place of the original lamps, replacing the GPIO peripheral of the original. A second Teensy emulates the analogue sounds and handles inputs from a miniature version of the original’s 8×8 button matrix. Source code (original and “rebooted”!) is available on GitHub, and videos of both the original and modern incarnation can be enjoyed below.

Synth DIY Facebook group member Craig Barnes has created a bi-timbral synth controller. With 64 split upper/lower channels of Control Voltage (CV), this Teensy 4.1-based wonder also features 56 channels of shift registers for digital control.

The controller features four LFOs for FM, TM, AM, and PWM (upper and lower). Two noise circuits and Voltage Controlled Amplifiers (VCAs) provide further sonic possibilities. This is a seriously impressive thing to do on protoboard, as attested by the sheer volume of wiring around back.

Yang Zhang, Gierad Laput, and Chris Harrison have developed Electrick: low-cost touch sensing using Electric Field Tomography (EFT). In their paper on the topic, the authors show techniques and examples for adding interactivity to otherwise static objects.

The electrically conductive material used can be spray or brush-coated into irregularly-shaped objects (compared to more typical applications like smartphones and tablets), including laser-cut or 3d-printed items.

A custom PCB featuring a Kinetis K20 MCU running Teensy 3.2 firmware hosts the voltage-controlled current source (VCCS), direct digital synthesizer (DDS), an ADC preamp, and a Bluetooth module for wireless data transmission. Read more on Chris or Yang‘s web sites, or check out the video below.

Trevor Flowers has a tiny computing obsession. To be clear, it’s not the obsession that’s small — it’s the computers themselves, which Trevor painstaking recreates in miniature to look — and even function — just like their full-size counterparts.

Trevor’s work can be seen all over Mastodon, as well as in Mountain View’s Computer History Museum. But the lilliputian marvel that caught our eye was a 1/3 scale replica of the 1978 DEC VT100 computer terminal, complete with functional Teensy 4.1-powered keyboard! Thanks to Teensy’s USB HID (Human Interface Device) capabilities, the diminutive DEC’s typing apparatus can be used with any modern computer, although it is intended to be paired with an SBC, like the Raspberry Pi, which can be concealed in the terminal’s case. A 3.5″ 640×480 TFT display provides sufficient resolution to emulate the VT100’s 80×24 character mode.

A pager motor inside the keyboard provides haptic feedback to give users confidence that their keystrokes were recognized, and USB serial allows the LEDs to be controlled by the connected SBC. More information about the project can be found on Hackaday, and a wide range of tiny art machines, from TRS-80s to NeXT workstations to Cray 1 supercomputers, can be found on Trevor’s web site. If you don’t have space for a tiny retrocomputer on your desk, you can also support Trevor’s art on Patreon, or by commissioning your own custom piece!

While many-channel audio solutions have existed for Teensy for some time, they were mostly based on the Cirrus Logic CS42448 codec, which has sadly been discontinued.

Australian PJRC forum member palmerr has taken up the mantle of multi-channel support with a new board based on the TI TLV320AIC3104 stereo codec. With four multiplexed codecs, each board features four “wing” boards for connecting pairs of TRS, XLR, or combo XLR connectors. The board is stackable, for up to 16 inputs and 16 outputs. The design is very CPU-efficient, using just 0.12% on a Teensy 4.0 to drive 16 output channels from a single sine generator.

Finished boards are available on Tindie, with Gerbers and a board-specific library available on GitHub. An extensive thread detailing the project’s evolution can be found on the PJRC forums.