A Colorful Way To Play Chess On An ATmega328

We’ve all seen those chess computers that consist out of a physical playing field, and a built-in computer that would indicate where you should put its pieces while inputting the position of your pieces in some way. These systems are usually found in a dusty cardboard box in a back room’s closet, as playing like this is fairly cumbersome, and a lot depends on the built-in chess computer.

This take by [andrei.erdei] on this decades-old concept involves an ATmega328p-based Arduino Pro Mini board, a nice wooden frame, and 4 WS2812-based 65×65 mm RGB 8×8 LED matrices, as well as some TTP223 touch sensors that allow one to control the on-board cursor. This is the sole form of input: using the UP and RIGHT buttons to select the piece to move, confirm with OK, then move to the new position. The chess program will then calculate its next position and indicate it on the LED matrix.

Using physical chess pieces isn’t required either: each 4×4 grid uses a special pattern that indicates the piece that occupies it.  This makes it highly portable, but perhaps not as fun as using physical pieces. It also kills the sheer joy of building up that collection of enemy pieces when you’ve hit that winning streak. You can look at the embedded gameplay video after the break and judge for yourself.

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Qt Arrives For Small Computers

There was a time when writing embedded systems meant never having to deal with graphical user interfaces, and spending long hours trying to free up a dozen bytes of ROM to add a feature. Nowadays, an embedded system is likely to have a screen and what would have been a huge amount of memory even for a PC a scant decade ago. Qt has long been a popular choice for building software on desktop platforms, and — while not as popular — has even run on phones for a while. Now there’s Qt for MCUs which is clearly targeting the IoT market that everyone is trying to capture. You can see the glitzy video for the new product, below.

We generally like Qt, and the move recently has been towards an HTML-like markup language called QML instead of directly manipulating widgets. We guess that’s a good thing. However, Qt isn’t just for user interfaces. It provides a wide range of services in a straightforward way

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Temperature Logging On The Last Frontier

In Alaska, the impact of climate change is easy to see. Already the melting permafrost is shifting foundations and rocking roads. Hotter summers are also turning food caches from refrigerators into ovens.

A permanent food cache. Via Wikipedia

[rabbitcreek]’s friend builds food caches with kids as part of a program to teach them traditional native activities. Food caches are usually inside buried boxes or small cabins raised on poles. Both are designed to keep hangry bears out. As you might expect, monitoring the temperature at these remote sites is crucial, so the food doesn’t spoil. His friend wanted a set-and-forget temperature monitoring system that could collect data for eight months over the winter.

The Alaska Datalogger carried a pretty serious list of requirements. It has to be waterproof, especially as ice and snow turn to water. Ideally, it should sip power and have a long battery life anyway. Most importantly, it has to be cheap and relatively easy for kids to build.

This awesome little data spaceship is designed around an O-ring used in domestic water purifiers. The greased up O-ring fits between two 3D printed enclosure halves that are shut tight with nylon bolts. Two waterproof temperature probes extend from the case—one inside the cache and the other outside in the elements. It’s built around an Adafruit Feather Adalogger and powered by an 18650 cell. The data is collected by visiting the site and pulling the SD card to extract the text file. There’s really no other way because the sites are far out of cell coverage. Or is there?

Though it probably wouldn’t survive the last frontier, this self-sufficient weather station is a simple solution for sunnier situations.

Returning Digital Watches To The Analog Age: Enter The Charliewatch

The Charliewatch by [Trammell Hudson] is one of those projects which is beautiful in both design and simplicity. After seeing [Travis Goodspeed]’s GoodWatch21 digital watch project based around a Texas Instruments MSP430-based SoC, [Trammell] decided that it’d be neat if it was more analog. This is accomplished using the CC430F5137IRGZR (a simpler member of the MSP430 family) and a whole bunch of 0603 SMD LEDs which are driven using Charlieplexing.

This time-honored method of using very few I/O pins to control many LEDs makes it possible to control 72 LEDs without dedicating 72 pins. The density makes animations look stunning and the digital nature melts away leaving a distinct analog charm.

A traditional sapphire crystal was sourced from a watchmaker for around 14€ as was the watch band itself. The rest is original work, with multiple iterations of the 3D printed case settling in on a perfect fit of the crystal, PCB, and CR2032 coin cell stackup. The watch band itself hold the components securely in the housing, and timekeeping is handled by a 32.768 kHz clock crystal and the microcontroller’s RTC peripheral.

The LEDs can be seen in both daylight and darkness. The nature of Charlieplexing means that only a few of the LEDs are ever illuminated at the same time, which does wonders for battery life. [Trammell] tells us that it can run for around six months before the coin cell needs replacing.

It’s completely open source, with project files available on the project’s Github page. We hope to see an army of these watches making appearances at all upcoming electronics-oriented events. Just make sure you lay off the caffeine as the process of hand-placing all those LEDs looks daunting.

A Friendly Reminder That You Might Be In Danger

Product recalls are one of those things that most people don’t pay attention to until things get really bad. If it’s serious enough for somebody to get hurt or even die, then the media will pick it up, but most of the time they simply pass by in silence. In fact, there’s a decent chance that you own a recalled product and don’t even know it. After all, it’s not like anyone is actually watching the latest product recalls in real-time.

Well actually, there might be one guy. [Andrew Kleindolph] has created a cute and cuddly gadget using CircuitPython on the Adafruit PyPortal to display the latest release from the United States Consumer Product Safety Commission (USCPSC). In a wonderfully ironic touch, the child’s unicorn boot that the device lives in is itself a recalled product; apparently kids could pull off the “horn” and choke on it.

The PyPortal is basically built for this kind of thing, allowing you to easily whip up a display that will scrape data from whatever online source you’re willing to write the code for. All [Andrew] had to do was pair it with a battery so the boot could go mobile occasionally (we’re told they’re made for walkin’), and design some 3D printed accoutrements such as a screen bezel and charging port.

As these recalls (thankfully) don’t come out quite so fast that you need it to update more than once or twice a week, it seems like this could also be an excellent application for an Internet-connected e-ink display.

DIY Geiger Counter Is Sure To Generate Clicks

On the outside, a Geiger counter seems like a complicated thing. And you might think a device that detects a dangerous, mostly invisible threat like radiation should be complicated. But they’re actually pretty simple. The Geiger-Muller tube does most of the work, which boils down to detecting brief moments of conductivity caused by chain reactions of charged particles in radioactive materials.

[Prabhat_] wanted to build a unique-looking Geiger counter, and we’d say that this slick, Star Trek-esque result succeeds. A well-organized display shows the effective dose rate, counts per minute, and cumulative dose, which can be displayed in either microsieverts or millirems. We dig the 3D printed case design, because we like to see form follow function.

The counter is powered by an 18650 cell that’s DC-to-DC boosted to 400+ volts. A NodeMCU processes the signal coming in from the G-M tube and expresses it in both clicks and LED blinks, both of which can be toggled on or off from the home screen. The alert threshold can be customized in the settings, which means the point at which green changes to red.

Click-click-click past the break for [prabhat_]’s great walk-through video, where he tests it with uranium ore and a thoriated gas lantern mantle.

If you want to take the opposite approach and get to clicking ASAP, well, fire up your hot glue gun and dump out your scrap bin.

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Spain’s First Open Source Satellite

[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.

The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.

The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.

Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.

The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.

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