Microcontrollers are small, no one is arguing that. On a silicon wafer the size of a grain of rice, you can connect a GPS tracker to the Internet. Put that in a package, and you can put the Internet of Things into something the size of a postage stamp. There’s one microcontroller that’s smaller than all the others. It’s the ATtiny10, and its brethren the ATtiny4, 5, and 9. It comes in an SOT-23-6 package, a size that’s more often seen in packages for single transistors. It’s not very capable, but it is very small. It’s also very weird, with a programming scheme that’s not found in other chips from the Atmel/Microchip motherbrain. Now, finally, we have a great tutorial on using the ATtiny10, and it comes from none other than [Ben Heck].
The key difference between the ATtiny10 and other AVRs is that the tiny10 doesn’t use the standard AVR ISP protocol for programming. Instead of six pins for power, ground, MISO, MOSI, SCK, and RST, this is a high-voltage programming scheme that needs 12 Volts. The normal AVR programmer can do it, but you need to build an adapter. That’s exactly what [Ben] did, using a single-sided perf board, a lot of solder, and some headers. It looks like a lot, but there’s really not much to this programmer board. There’s a transistor and an optocoupler. The only thing that could make this programmer better is an SOT-23 ZIF socket. This would allow bare tiny10s to be programmed without first soldering them to a breakout board, but ZIF sockets are expensive to begin with, and the prices on SOT-23 sockets are absurd.
Programming the device was a matter of loading Atmel Studio and going through the usual AVR rigamarole, but Ben was eventually able to connect a light sensor to the tiny10 and have it output a value over serial. This was all done on a device with only 32 Bytes of RAM. That’s impressive, and one of the cool things about the smallest microcontroller you can buy.
[Dave] aka [Mubes] has been working on the Blue Pill platform which is a STM32F103C8 board. While they don’t natively output video, it’s a feature that provides a handy tool to have for debugging in order to see what’s going on in your code. However, if the video code takes up all of the processor power and memory there’s not much point. [Dave]’s video output program, on the other hand, takes up only 1200 bytes of RAM and 24% of the processor for a 50×18 text display over VGA, leaving a lot of room left for whatever else you need the tiny board to do.
Video output on a device this small and lightweight is an impressive feat, especially while saving room for other tasks. This brings it firmly out of the realm of novelty and into the space of useful tools to keep around. If you want to try the same thing on an ATtiny, though, you might have to come up with some more impressive tricks.
From cars to refrigerators, it seems as if every new piece of tech is connected to the Internet. For better or for worse, we’re deep into the “Internet of Things”. But what about your camera? No, not the camera in your smartphone; that one’s already connected to the Internet and selling your secrets to the highest bidder. Don’t you think your trusty DSLR could be improved by an infusion of Wide Area Networking?
Regardless of what you’re answer to that question might be, [Thomas Kittredge] decided his life would be improved by making his beloved Canon EOS Rebel T6 an honorary member of the Internet of Things. Truth be told he says that he hasn’t quite figured out an application for this project. But since he was looking to mess around with both the LTE-enabled Particle Boron development board and designing his own PCB for professional production, this seemed a good a way to get his feet wet as any.
The resulting board is a fairly simple “shield” for the Particle Boron that let’s [Thomas] trigger up to two cameras remotely over the Internet or locally with Bluetooth. If LTE isn’t your sort of thing though, don’t worry. Since the Boron follows the Adafruit Feather specification, there’s a whole collection of development boards with various connectivity options that this little add-on can be used with.
In the GitHub repository, [Thomas] has put up the files for the PCB, the STLs for the 3D printed enclosure, and of course the firmware source code to load onto the Particle board. He currently has code to expose the two shutter triggers as functions the the Particle Cloud API, as well as a practical example that fires off the camera when specific words are used in a Slack channel.
[Maarten Tromp] recently took the time to document some of the unusual and creative electronic projects he received as gifts over the years. These gadgets were created in the early 2000’s and still work flawlessly today. Two of our favorites are shown here: Hardware Tetris Unit (shown in the image above) and Heap of Electronic Parts.
Heap of Electronic Parts was a kind of hardware puzzle and certainly lives up to its name. It’s a bunch of parts soldered in a mystifying way to the backs of four old EPROMs — the chips with the little window through which UV is used to erase the contents. Assured that the unit really did have a function, [Maarten] eventually figured out that when placed in sunlight, the device ticks, buzzes, and squeals. [Jeroen] had figured out that the EPROMs could act like tiny solar cells when placed in sunlight, and together the four generate just enough power to drive an oscillator connected to a piezo speaker. It still chirps happily away, even today.
Hardware Tetris Unit was a black box intended to be plugged into a serial port. With a terminal opened using the correct serial port settings, a fully-functional Tetris game using ASCII-art graphics could be played. It was even self-powered from the serial port pins.
Inside Hardware Tetris is an AVR microcontroller with some level shifters, and the source code and schematics are available for download. 14 years later, computers no longer have hardware serial ports but [Maarten] says a USB-to-serial converter worked just fine and the device still functions perfectly.
There are a couple more devices documented on [Maarten]’s gifts page, including a Zork-inspired mini text adventure and a hardware board that does some trippy demos on an old Nokia color LCD. [Maarten]’s friend [Jeroen Domburg] (aka Sprite_tm) had a hand in creating most of the gadgets, and he’s someone whose brilliant work we have had the good fortune to feature many times in the past.
Watchdog timers are an often overlooked feature of microcontrollers. They function as failsafes to reset the device in case of a software failure. If your code somehow ends up in an infinite loop, the watchdog will trigger. This is a necessity for safety critical devices. If the firmware in a pacemaker or a aircraft’s avionics system gets stuck, it isn’t going to end well.
In this oldie-but-goodie, [Jack Ganssle] provides us with a great write up on watchdog timers. This tells the story of a failed Clementine spacecraft mission that could have been saved by a watchdog, and elaborates on the design and implementation of watchdog techniques.
If you’re designing a device that needs to be able to handle unexpected failures, this article is definitely worth a read. [Jack] explains a lot of traps of using these devices, including why internal watchdogs can’t always be trusted and what features make for a great watchdog.
People often get the impression that home built hardware is destined to have a certain amateurish look or feel to it. It’s as though just because you didn’t buy it in a store, it will look cheap or thrown together. While it’s true a hacked together device could look like it was built from the parts bin (and to be fair, sometimes it is), there are plenty of examples of DIY hardware that could give commercial offerings a run for their money.
A case in point is this fantastic ESP8266 air conditioner controller created by [Sitinut Waisara] (Google Translate). Between the simple yet elegant 3D printed enclosure to the very slick user interface on its OLED screen, this project could easily pass as a commercial device. In fact, we’ve seen commercial offerings that didn’t look half this good, let alone offer the same features for what this cost in components and printer filament. It’s a perfect example of what the modern hacker or maker is capable of with the wide array of tools and components currently available to us.
What’s perhaps the most impressive about this project, especially given how good it looks on the outside, is how little there really is on the inside. Beyond the NodeMCU board and SSD1332 OLED display, the only components inside the device are the three tactile buttons, a photoresistor so it can dim the display’s brightness based on ambient light level, an IR LED so it can send commands to the AC unit, and a handful of passives. The hardware side of this design is so simple that [Sitinut] was able to put the whole thing together on a scrap of perfboard. Not that you’d be able to tell when it gets installed into the 3D printed wall-mount enclosure, complete with printed button caps.
While the hardware side of the project might be rather light, the software is anything but. [Sitinut] really went all-in writing his code for the ESP, adding in the little features like the automatic screen dimming and pulling the current time from NTP that often get overlooked in our rush to get a project out the door. He even included a whole collection of icons to display on the OLED screen, which goes a long way towards selling that professional look. But his effort wasn’t limited to cosmetics or clever features, there was also plenty of work put into decoding the IR signals used to control the AC unit and getting all the features and functions plugged into MQTT.
[foamyguy] loves Python and messing around with electronics. Boards such as Adafruit’s Circuit Playground Express make it easy for him to take both anywhere. He recently found himself wanting to program Circuit Python boards in the field, but doesn’t always have a laptop on him. So he created an Android app to make on-the-go programming fast and easy.
Using CircuitPython Editor and one or two USB cables, you can program Circuit Python boards with most Android device, including Tinkerboards. It features serial communication, a basic code editor, and a REPL sandbox for code-based castle building. [foamyguy]’s most recent addition to this work in progress is a macro creation tool that lets you edit and store modular, repeatable tasks, like turning all the NeoPixels blue, or lighting them up in a smiley face pattern. The Circuit Python board will draw its power from the Android device, so keep that in mind before you program some crazy light show.