Tiny RISC Virtual Machine Is Built For Speed

April 28, 2022 by Bryan Cockfield 13 Comments

Most of us are familiar with virtual machines (VMs) as a way to test out various operating systems, reliably deploy servers and other software, or protect against potentially malicious software. But virtual machines aren’t limited to running full server or desktop operating systems. This tiny VM is capable of deploying software on less powerful systems like the Raspberry Pi or AVR microcontrollers, and it is exceptionally fast as well.

The virtual machine is built from scratch, including the RISC processor with only 61 opcodes, a 64 bit core, and runs code written in his own programming language called “Brackets” or in assembly. It’s designed to be modular, so only those things needed for a given application are loaded into the VM. With these design criteria it turns out to be up to seven times as fast as comparably small VMs like NanoVM. The project’s creator, [koder77], has even used its direct mouse readout and joystick functionality to control a Raspberry Pi 3D camera robot.

For anyone looking to add an efficient VM to a small computing environment, [koder77] has made the project open-source on his GitHub page. This also includes all of the modules he has created so far which greatly expand the project’s capabilities. For some further reading on exceedingly tiny virtual machines, we featured this project way back in 2012 which allows users to run Java on similar hardware.

Flashing TI Chips With An ESP

April 3, 2022 by Bryan Cockfield 29 Comments

Texas Instruments is best known to the general public for building obsolete calculators and selling them at extraordinary prices to students, but they also build some interesting (and reasonably-priced) microcontrollers as well. While not as ubiquitous as Atmel and the Arduino platform, they can still be found in plenty of consumer electronics and reprogrammed, and [Aaron] aka [atc1441] demonstrates how to modify them with an ESP32 as an intermediary.

Specifically, the TI chips in this build revolve around the 8051-core microcontrollers, which [Aaron] has found in small e-paper price tags and other RF hardware. He’s using an ESP32 to reprogram the TI chips, and leveraging a web server on the ESP in order to be able to re-flash them over WiFi. Some of the e-paper displays have built-in header pins which makes connecting them to the ESP fairly easy, and once that’s out of the way [Aaron] also provides an entire software library for interacting with these microcontrollers through the browser interface.

Right now the project supports the CC2430, CC2510 and CC1110 variants, but [Aaron] plans to add support for more in the future. It’s a fairly comprehensive build, and much better than buying the proprietary TI programmer, so if you have some of these e-paper displays laying around the barrier to entry has been dramatically lowered. If you don’t have this specific type of display laying around, we’ve seen similar teardowns and repurposing of other e-paper devices in the past as well.

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Careful Cuts Lets Logger Last A Year On A Coin Cell

March 14, 2022 by Bryan Cockfield 21 Comments

Coin cells are great for backup power for things like real-time clocks, or even for powering incredibly small mechanical devices like watches. But for something like a data logger, running on a standard microcontroller, most people would reach for a lithium cell of some sort. Not so with this build, though, which squeezes every joule of energy from a coin cell in order to run a data logger for a full year.

Most of the design and engineering required to improve the efficiency of the data logger involve standard practices for low-power devices such as shutting off unnecessary components and putting the device to sleep when not actively running, but this build goes far beyond that. The Vcc pin on the RTC was clipped which disables some of its internal logic but still keeps its basic functionality intact.

All of the voltage regulators were removed or disabled in favor of custom circuitry that doesn’t waste as much energy. The status and power LEDs were removed where possible, and the entire data logger is equipped with custom energy-efficient code as well.

If you’re starting a low-power project, even one that isn’t a datalogger, it’s worth checking out this build to see just how far you can go if you’re willing to hack at a PCB with cutting tools and a soldering iron. As to why this data logger needed such a low power requirement, it turns out it’s part of a kit being used in classrooms and using a coin cell brought the price of the entire unit down tremendously. Even if you have lithium cells on hand, though, it’s still worthwhile to check out the low power modes of your microcontroller.

Thanks to [Adrian] for the tip!

ESP32 Virtual Machine Lets You Change Programs On The Fly

February 27, 2022 by Lewin Day 30 Comments

Often, reprogramming a microcontroller involves placing it in reset, flashing the code, and letting it fire back up. It usually involves shutting the chip down entirely. However, [bor0] has built a virtual machine that runs on the ESP32, allowing for dynamic program updates to happen.

The code is inspired by the CHIP-8, a relatively ancient interpreter that had some gaming applications. [bor0] had already created a VM simulating the CHIP-8, and repurposed it here, taking out the gaming-related drawing instructions and replacing them with those that control IO pins. Registers have also been changed to 16 bits for added flexibility and headroom.

It’s probably not something with immediate ground-breaking applications for most people, but it’s a different way of working with and programming the ESP32, and that’s pretty neat.

The ESP32 is a powerful chip, too, as we all know – and it makes a great 8-bit emulator to boot. Sound off in the comments with your thoughts on what would make a killer application for the ESP32 VM!

[Thanks to satancete for the tip!]

Floppy Interfacing Hack Chat With Adafruit

January 31, 2022 by Dan Maloney 44 Comments

Join us on Wednesday, February 2 at noon Pacific for the Floppy Interfacing Hack Chat with Adafruit’s Limor “Ladyada” Fried and Phillip Torrone!

When a tiny fleck of plastic-covered silicon can provide enough capacity to store a fair percentage of humanity’s collected knowledge, it may seem like a waste of time to be fooling around with archaic storage technology like floppy disks. With several orders of magnitude less storage capacity than something like even the cheapest SD card or thumb drive, and access speeds that clock in somewhere between cold molasses and horse and buggy, floppy drives really don’t seem like they have any place on the modern hacker’s bench.

Or do they? Learning the ins and out of interfacing floppy drives with modern microcontrollers is at least an exercise in hardware hacking that can pay dividends in other projects. A floppy drive is, after all, a pretty complex little device, filled with electromechanical goodies that need to be controlled in a microcontroller environment. And teasing data from a stream of magnetic flux changes ends up needing some neat hacks that might just serve you well down the line.

So don’t dismiss the humble floppy drive as a source for hacking possibilities. The folks at Adafruit sure haven’t, as they’ve been working diligently to get native floppy disk support built right into CircuitPython. To walk us through how they got where they are now, Ladyada and PT will drop by the Hack Chat. Be sure to come with your burning questions on flux transitions, MFM decoding, interface timing issues, and other arcana of spinning rust drives.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 2 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Custom Piano Tickles The Ivories

January 28, 2022 by Bryan Cockfield 6 Comments

The core ethos of “hacking” is usually interpreted as modifying something for a use that it wasn’t originally built for. Plenty of builds are modifications or improvements on existing technology, but sometimes that just isn’t enough. Sometimes we have to go all the way down and build something completely from scratch, and [Balthasar]’s recent piano-like musical instrument fits squarely into this category.

This electronic keyboard is completely designed and built from scratch, including the structure of the instrument and the keys themselves. [Balthasar] made each one by hand out of wood and then built an action mechanism for them to register presses. While they don’t detect velocity or pressure, the instrument is capable of defining the waveform and envelope for any note, is able to play multiple notes per key, and is able to change individual octaves. This is thanks to a custom 6×12 matrix connected to a STM32 microcontroller. Part of the reason [Balthasar] chose this microcontroller is that it can do some of the calculations needed to produce music in a single clock cycle, which is an impressive and under-reported feature for the platform.

With everything built and wired together, the keyboard is shockingly versatile. With the custom matrix it is easy to switch individual octaves on the piano to any range programmable, making the 61-key piano capable of sounding like a full 88-key piano. Any sound can be programmed in as well, further increasing its versatility, which is all the more impressive for being built from the ground up. While this build focuses more on the electronics of a keyboard, we have seen other builds which replicate the physical action of a traditional acoustic piano as well.

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I2C To The Max With ATtiny

January 18, 2022 by Bryan Cockfield 28 Comments

The Arduino is a powerful platform for interfacing with the real world, but it isn’t without limits. One of those hard limits, even for the Arduino MEGA, is a finite number of pins that the microcontroller can use to interface with the real world. If you’re looking to extend the platform’s reach in one of your own projects, though, there are a couple of options available. This project from [Bill] shows us one of those options by using the ATtiny85 to offload some of an Arduino’s tasks using I2C.

I2C has been around since the early 80s as a way for microcontrollers to communicate with each other using a minimum of hardware. All that is needed is to connect the I2C pins of the microcontrollers and provide each with power. This project uses an Arduino as the controller and an arbitrary number of smaller ATtiny85 microcontrollers as targets. Communicating with the smaller device allows the Arduino to focus on more processor-intensive tasks while giving the simpler tasks to the ATtiny. It also greatly simplifies wiring for projects that may be distributed across a distance. [Bill] also standardizes the build with a custom development board for the ATtiny that can also double as a shield for the Arduino, allowing him to easily expand and modify his projects without too much extra soldering.

Using I2C might not be the most novel of innovations, but making it easy to use is certainly a valuable tool to add to the toolbox when limited on GPIO or by other physical constraints. To that end, [Bill] also includes code for an example project that simplifies the setup of one of these devices on the software end as well. If you’re looking for some examples for what to do with I2C, take a look at this thermometer that communicates with I2C or this project which uses multiple sensors daisy-chained together.

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