Blog Posts

Adding new features to old computers is one of our favorite project types, as it keeps hardware out of the trash and gives the device a new lease on life.

Philip Freidin’s description of the EBTKS project certainly sounds like it has been an incredible journey, and the functionality that it adds to the HP-85 is positively mind-blowing.

A brief overview of the EBTKS’ features includes:

• tape drive emulation, using a 16GB mSD card to hold up to 200,000 tapes
• floppy and Winchester disk drive emulation via mSD
• ROM, RAM and Extended memory emulation
• jumperless configuration via text file
• over 70 new keywords
• an EPS32 co-processor (under development)

Find out more and order yours on the EBTKS web page.

Trip replaced the internals of a 1K mouse with a Teensy 4.0 for 8 times faster updates!

A 4K gaming mouse doesn’t mean it has four times as many pixels as a 1080p display — but rather that it polls at 4000Hz, meaning my movements are sent to the connected PC 4000 times per second. And just like TVs, 8K mice are already starting to be seen in the market.

Paired with a Pixart PMW3360DM-T2QU image sensor, which captures images at a rate of up to 12000 fps, the integrated Teensy transmits movement up to 8000 times per second over a shortened USB cable, in order to optimize transmission. More information can be found on the project’s GitHub page.

We’ve covered MicroCoreLabs’ emulation projects before, including a cycle-accurate Zilog Z80 Emulator for the TRS-80 Model III, and a drop-in that resulted in the world’s fastest Commodore 64.

Well, Ted is at it again, this time emulating the venerable Intel 8088, in his MCL86+ 8088 replacement board for the IBM PC/XT and clones.

As always, this Teensy 4.1-based project offers both cycle-accurate 4.77MHz and accelerated modes. Running the SuperSoft Diagnostic ROM with 256KB of RAM in the Teensy 4.1’s memory at 800Mhz, with 8088 cycle accuracy disabled, performance is estimated at around 10x, although the disk drives and keyboard were unable to keep up, somewhat limiting practical use. As always, source for cycle-accurate and accelerated firmware is available on GitHub, along with schematics and fabrication files for the PCB that performs voltage level shifting and adapts it to the 8088 socket. Be sure to watch below as MCL86+ takes on the emulator-crushing 8088 MPH demo!

We’ve seen a fair number of Teensy-based looping tools in recent years, but this one by Donkeyahoy is rather unique in that it uses a literal loop of analog magnetic audio tape, rather than a more modern, digital approach.

The motor driving the tape can be adjusted over a wide range (0-4000 capstan rpm, 0-99 tape inches per second), allowing the playback speed to vary from excruciatingly slow to absurdly fast (with the pitch changing along with it). Control voltage or an external DAW can also be used to adjust speed. The same external control can be used to reverse the loop (great for backmasking subliminal messages!) as well as via the direction switch. A built-in LCD shows speed and direction, which is useful if you want to return to the original recording speed. The two-track system also has left/right stereo mic and line inputs, line and headphone outputs, and classic VU meters for monitoring levels. Learn more on the project’s GoFundMe page.

grblHAL is a project started by Norwegian software developer Terje Io to allow the GRBL CNC software to be abstracted from microcontroller-dependent code, facilitating its adaptation to various boards.

PhilB created a breakout board “unkit” (meaning SMT components come pre-soldered so you just have to add through-holes) for the Teensy 4.1, providing 5-axis control for a fraction of the cost of commercial solutions.

The (un)kit is available on Tindie, though Gerbers are also available on GitHub, along with documentation and more. While USB is the default connection, an Ethernet MagJack footprint enables upgrading for more reliable G-Code feeding. The main grblHAL site also contains a great resources page.

We love seeing ham radios built around Teensy, but to paraphrase Xzibit, Jack (W8TEE) and Al (AC8GY) heard you like ham radio kits, so they made the JackAL (get it?) add-on kit for your µBITX transceiver kit, so you can…well we’ll get to what it lets you do…

Rewinding for a moment, the µBITX itself is a HF SSB/CW transceiver kit (that’s High Frequency, Single Side-Band/Continuous Waveform aka Morse code) with digital tuning, a Morse code keyer, and more, designed to be an approachable, understandable radio that you can build yourself. The JackAL add-on board adds a high-resolution 800×480 TFT touch screen, hardware AGC (automatic gain control), and extensive DSP audio functions. A large rotary encoder facilitates fine-tuning, and user presets for most settings are conveniently stored in EEPROM. The kit comes with SMD components pre-populated — just bring your own Teensy 3.6 and Audio Adaptor Board, plus the display of your choice. More information can be found at the µBITX enthusiast site ubitx.net, as well as a dedicated Groups.io site.

Northstrix (Max) has been working on various iterations of the Midbar DIY Hardware Data Vault, with the latest V3.0 using Teensy 4.1.

These days, everyone uses a password manager (right? if you’re reading this and not using a password manager, remove all of those Post-It notes from around your monitor and go download Bitwarden right now, set it up, and come back when you’re done — we’ll wait!), but Northstrix posits that using a PC-based password manager leaves it vulnerable to malicious processes running on the same machine.

The latest version of Midbar features password, credit card, phone number, and note vaults, plus an encrypted book reader, a data encryptor/decryptor, and data hasher. Teensy’s USB Host functionality enables the connection of a keyboard. Up to 16 logins and 10 credit cards can be stored in EEPROM, with mSD card storage expanding those numbers greatly depending on available storage. 3DES + AES + Blowfish + Serpent Encryption keeps your data safe, and EEPROM is checked for tampering with each unlock. Full instructions to make your own can be found on Instructables, with source code and more project details available on GitHub.

OD_A has created a video synthesizer that uses a Teensy 3.5 to oscillate frequencies into the RGB channels of a VGA signal.

The interface consists of individual sliders for each of the red, green, and blue channels, which are then “mixed” with a video input (in the style of a DJ mixer) to produce glitchy visuals akin to unusually beautiful VHS tracking skew. After some op-amp and other circuitry issues, OD_A was able to figure out a way to abuse the VGA spec to achieve the desired results, thanks to guidance from the PJRC forum community. See the results in the video below, and check out more of OD_A’s projects and hacks at os-is.me.

Radio control systems can be expensive and confusing with their various incompatible protocols (FHSS, DSSS, and so on), but Malcolm Messiter “simplified” the whole paradox by just making their own Teensy-powered transmitter and receiver from scratch.

The transmitter uses a Teensy 4.1, and the receiver a 4.0, both equipped with a Nordic nRF24L01+ 2.4GHz transceiver, providing a range of approximately 2.5km! The current firmware supports 16 channels, 12-bit servo resolution, four flight modes, 32 mixes, 99 model memories with import and export, FHSS (Frequency Hopping Spread Spectrum), PWN and SBUS output, failsafe on any channel, digital trims and graphic curves on all channels, and user-defined channel names. All of this is managed via a GUI on a Nextion color touch screen. Binding is via a 64-bit ID for maximum security. These features dramatically exceed the specs of many high-end radio systems costing hundreds, or even thousands of dollars, and are demonstrated effortlessly controlling an SAB Urukay in the video below.

YouTuber Zack Freedman wanted to improve his video-editing workflow without spending $100s on new hardware, so he grabbed a Teensy and committed to a one-weekend time limit over which to build his own control surface.

Essentially three normal and one giant knob plus a weird mechanical keyboard, the project is mostly 3d-printed beyond these components, supporting passives, and basic hardware. Source code, design files, and BOM can be found on GitHub, while the accompanying video not only shows you how to put it all together, but also provides a slew of great tips for successful rapid prototyping.