Before the World Wide Web became ubiquitous as the de facto way to access electronic information, there were many other ways of retrieving information online. One of the most successful of these was Minitel, a French videotex service that lasted from 1980 all the way until 2012. But just because the service has been deactivated doesn’t mean its hardware can’t be used for modern builds like this Arduino-based operating system. (Google Translate from French)
Called ZARDOS, the operating system is built to run on an Arduino MEGA although a smaller version is available for the Uno. The Arduino is connected by a serial cable to the Minitel terminal. It can take input from a keyboard and PS/2 mouse and displays video on the terminal screen with the same cable. There is functionality built-in for accessing data on a cartridge system based on SD cards which greatly expands the limited capabilities of the Atmel chip as well, and there is also support for a speaker and a Videotex printer.
Even though the build uses a modern microcontroller, it gives us flashbacks to pre-WWW days with its retro terminal. All of the code is available on the project site for anyone looking to build an Arduino-based operating system, although it will take a little bit of hardware hacking to build a Minitel terminal like this. Either way, it’s a great way to revive some antique French hardware similar to a build we’ve seen which converts one into a Linux terminal.
Thanks to [troisieme_type] for the tip!
While the ATMega328 is “mega” for a microcontroller, it’s still a fairly limited platform. It has plenty of I/O and working memory for most tasks, but this Battleship game that [thorlancaster328] has put together really stretches the capabilities of this tiny chip. Normally a Battleship game wouldn’t be that complicated, but this one has audio, an LED display, and can also play a fine rendition of Nyan Cat to boot, which really puts the Atmel chip through its paces.
The audio is played through a 512-byte buffer and an interrupt triggers the microcontroller when to fill the buffer while it works on the other processes. The 12×12 LED display is also fed through a shift register triggered by the same interrupt as the audio, and since the build uses so many shift registers the microcontroller can actually output four separate displays (two players, each with a dispaly for shots and one for ships). It will also eventually support a player-vs-computer mode for the battleship game, and also has a mode where it plays Nyan cat just to demonstrate its own capabilities.
We’re pretty impressed with the amount of work this small microcontroller is doing, largely thanks to code optimization from its creator [thorlancaster328]. If there’s enough interest he also says he will provide the source code too. Until then, be sure to check out this other way of pushing a small microcontroller to its limits.
Thanks to [Thinkerer] for the tip!
When [Alain] wanted to use some of the new TinyAVR 0 chips — specifically, the Attiny406 — it seemed overkill to use the Windows IDE. There are plenty of sources of information on programming other AVR chips using simple command line tools, but not for these newer 0-series parts which use a new programming protocol known as UPDI. That led to a deep diving into how to program a TinyAVR 0 with a text editor, makefile, and USB-to-serial cable.
The Attiny406 has 4K of flash, 256 bytes of RAM and can run at 20 MHz with no external clock. You might think programming would be similar to a regular AVR part, but these tiny devices use UPDI (Unified Programming and Debug Interface) which uses 3 pins for programming. Older devices used different protocols.
It is very easy to create a UPDI programmer. A USB to logic-level serial cable and a 4.7K resistor is all it takes. There’s Python code that knows how to drive the protocol, too. You can also use the logic-level serial port on the Raspberry Pi with some device tree modifications explained in the code’s documentation.
[Alain] made a nice breakout board for the device. It fits a breadboard, allows for 5V or 3.3V operation, and has an LED and switch. Nothing fancy, but handy. Once you know how to ship a hex file to the chip, the rest is pretty standard. While the AVR version of gcc doesn’t cross-compile for the ATTiny out of the box, there is a device pack from Microchip that enables that feature.
The trend is to go to bigger processors, not smaller, but when you need to cram something in a small space, save a few pennies per unit, or draw very little power, these tiny processors can be just the ticket. The processors may be small, but if you work you can do some pretty big things with them.
While it might be nice to use a $4,000 oscilloscope in a lab at a university or well-funded corporate environment, a good portion of us won’t have access to that kind of equipment in our own home shops. There are a few ways of getting a working oscilloscope without breaking the bank, though. One option is to find old CRT-based unit for maybe $50 on craigslist which might still have 60% of its original 1970s-era equipment still operational. A more reliable, and similarly-priced, way of getting an oscilloscope is to just convert a device you already have.
The EspoTek Labrador is an open-source way of converting a Raspberry Pi, Android device, or even a regular run-of-the-mill computer into a working oscilloscope. It’s a small USB device with about a two square inch PCB footprint that includes some other features as well like a signal generator and logic analyzer. It’s based on an ATxmega which is your standard Arduino-style AVR microcontroller but geared for low power usage. It looks as though it is pretty simple to use as well, and the only requirements are that you can install the software needed for the device on whatever computing platform you decide to use.
While the Labrador is available for sale at their website, it is definitely a bonus when companies offer products like this but also release the hardware and software as open source. That’s certainly a good way to get our attention, at least. You can build your own if you’d like, but if you’d rather save the time you have pre-built options. And it doesn’t hurt that most of the reviews of this product seem to be very favorable (although we haven’t tried one out ourselves). If you’d prefer an option without a company backing it, though, we have you covered there too.
If you’re building a cubesat, great, just grab a microcontroller off the shelf, you probably don’t need to worry about radiation hardening. If you’re building an experiment for the ISS, just use any old microcontroller. Deep space? That’s a little harder, and you might need to look into radiation tolerant and radiation hardened microcontrollers. Microchip has just announced the release of two micros that meet this spec, in both radiation-tolerant and radiation-hardened varieties.
The new devices are the SAMV71Q21RT (radiation-tolerant) and the SAMRH71 (rad-hard), both ARM Cortex-M7 chips running at around 300 MHz with enough RAM to do pretty much anything you would want to do with a microcontroller. Peripherals include CAN-FD and Ethernet-AVB, analog front-end controllers, and the usual support for I2C, SPI, and other standards. This chip does it in space, and comes in a ceramic quad flat package with gold lead frames. These are beautiful devices.
Microchip has an incredible number of space-rated, rad-hard hardware; this is mostly due to their acquisition of Atmel a few years ago, and yes, it absolutely is possible to build a rad-hard Arduino Mega using the chip, space rated.
Of course, there are very, very, very few people who would actually ever need a rad-hard microcontroller; I would honestly expect this to be relevant to only one or two people reading this, and they too probably got the press release. If you’ve ever wanted to build something that goes to space, and you’d like to over-engineer everything about it, you now have the option for an ARM Cortex-M7.
For many projects that require control of air pressure, the usual option is to hook up a pump, maybe with a motor controller to turn it on and off, and work with that. If one’s requirements can’t be filled by that level of equipment and control, then it’s time to look at commercial regulators. [Craig Watson] did exactly that, but found the results as disappointing as they were expensive. He found that commercial offerings — especially at low pressures — tended to leak air, occasionally reported incorrect pressures, and in general just weren’t very precise. Out of a sense of necessity he set out to design his own electronically controlled, closed-loop pressure regulator. The metal block is a custom manifold with valve hardware mounted onto it, and the PCB mounted on top holds the control system. The project logs have some great pictures and details of the prototyping and fabrication process.
This project was the result of [Craig]’s work on a microfluidics control system, conceived because he discovered that much of the equipment involved in these useful systems is prohibitively expensive for small labs or individuals. In the course of developing the electronic pressure regulator, he realized it could have applications beyond microfluidics control, and created it as a modular device that can easily be integrated into other systems and handle either positive or negative pressure. It’s especially well-suited for anything with low air requirements and a limited supply, but with a need for precise control.
While many of the Arduino platforms are great tools for gaining easy access to microcontrollers, there are a few downsides. Price and availability may be the highest on the list, and for those reasons, some have chosen to deploy their own open-source Arduino-compatible boards.
The latest we’ve seen is the Franzininho, an Arduino Gemma-like board that’s based on the ATtiny85, a capable but tiny microcontroller by Atmel in a compact 8-pin configuration. This board has everything the Gemma has, including a built-in LED and breakout pins. One of the other perks of the Franzininho over the Gemma is that everything is based on through-hole components, making the assembly much easier than the surface mount components of the Gemma.
It’s worth noting that while these boards are open source, the Arduinos are as well. It’s equally possible to build your own 100% identical Arduino almost as easily. If you want more features, you can add your own by starting from one of these platforms and do whatever you want with it, like this semi-educational Atmel breakout board.
Thanks to [Clovis] for the tip!