Year: 2019

Irène Joliot-Curie And Artificial Radioactivity

January 8, 2019 by 41 Comments

When Marie and Pierre Curie discovered the natural radioactive elements polonium and radium, they did something truly remarkable– they uncovered an entirely new property of matter. The Curies’ work was the key to unlocking the mysteries of the atom, which was previously thought to be indivisible. Their research opened the door to nuclear medicine and clean energy, and it also led to the development of nuclear weapons.

Irène Joliot-Curie, her husband Frédéric, and many of their contemporaries were completely against the use of nuclear science as a weapon. They risked their lives to guard their work from governments hell-bent on destruction, and most of them, Irène included, ultimately sacrificed their health and longevity for the good of society. Continue reading “Irène Joliot-Curie And Artificial Radioactivity” →

An Electronic Love Letter To The Wind

January 8, 2019 by 9 Comments

Home weather stations are a great way for hackers and makers to put their skills to practical use. After all, who wants to hear the current conditions for the whole city when they could setup their own station which drills that information down to their very own street? Such a setup doesn’t need to be any more complex than a temperature sensor wired up to a microcontroller, but then not all of us are quite the weather fanatic that [Richard] clearly is.

The system he’s built to monitor the wind over his home is, to put it mildly, incredible. We might not all share the obsession [Richard] apparently has with the wind, but we can certainly respect the thought and design that went into this comprehensive system. From his scratch built anemometer to the various ways he’s come up with to display the collected environmental data throughout his home, if this build doesn’t inspire you to hack together your own weather station then nothing will.

At the heart of the system is the anemometer itself, which makes use of several scavenged parts such as the bottom halves of plastic Easter eggs as wind cups. The cups spin on a short length of M5 threaded rod inside of a 635ZZ bearing, which ultimately rotates a “light chopper” placed between a red LED and a OPL550A optical sensor. In a particularly nice touch, [Richard] has even included a few power resistors arranged around the moving parts to use as a heater which keeps the device from freezing up when the temperature drops. The sensor creates eight digital pulses per revolution, and feeds data into the base station though a 30 meter (98 feet) cable.

From there, the base station uses an ESP8266 to upload wind and temperature data to ThingSpeak and Weather Underground to be viewed through their respective web interfaces and applications. The project really could have ended here and still been impressive in its own right, but the station also includes 433 MHz and NRF24L01 transmitters to send the data to the other display devices which [Richard] has designed.

The 433 MHZ display is built into the frame of a lantern, and shows the current time and temperature on an LED readout as well as historical wind and temperature graphs on a 2.2 inch ILI9341 TFT screen which [Richard] has rotated into a portrait layout. There’s a red light on top that blinks whenever a signal is received to show that the system is working, and even a touch sensor which can be used to turn off the TFT screen at a tap if you’re not interested in seeing the full charts.

The other display, which [Richard] calls the “picture frame” utilizes a dizzying array of single LEDs, a handful of digital LED readouts, and even an OLED screen for good measure. They all work together to show the current wind speed as well the averages for the past day in three hour segments. As this display features a real time display of current wind conditions and averages for as short a period of two minutes, it uses the NRF24L01 receiver to get data from the base station at a rate of 3 Hz.

In the past we’ve seen 3D printed weather stations, and of course some pretty simple affairs using little more than an ESP8266 board and some sensors. But few have ever put so much thought into how to present the collected data to the user. If you’re serious about knowing what it’s like outside the confines of your bunker, [Richard] has got some tricks to show you.

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Goodbye Chevy Volt, The Perfect Car For A Future That Never Was

January 8, 2019 by 164 Comments

A month ago General Motors announced plans to wind down production of several under-performers. At the forefront of news coverage on this are the consequences facing factories making those cars, and the people who work there. The human factor associated with the closing of these plants is real. But there is also another milestone marked by the cancellation of the Volt. Here at Hackaday, we choose to memorialize the soon-to-be-departed Chevrolet Volt. An obituary buried in corporate euphemisms is a whimper of an end for what was once their technological flagship car of the future.

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Being An SPI Slave Can Be Trickier Than It Appears

January 8, 2019 by 10 Comments

Interfacing with the outside world is a fairly common microcontroller task. Outside of certain use cases microcontrollers are arguably primarily useful because of how easily they can interface with other devices. If we just wanted to read and write some data we wouldn’t have gotten that Arduino! But some tasks are more common than others; for instance we’re used to being on the master side of the interface equation, not the slave side. (That’s the job for the TI engineer who designed the temperature sensor, right?) As [Pat] discovered when mocking out a missing SPI GPIO extender, sometimes playing the other role can contain unexpected difficulties.

The simple case for a SPI slave is exactly that: simple. SPI can be wonderful in its apparent simplicity. Unlike I2C there are no weird addressing schemes, read/write bits, stop and start clock conditions. You toggle a clock line and a bit of data comes out, as long as you have the right polarity schemes of course. As a slave device the basic algorithm is of commensurate complexity. Setup an interrupt on the clock pin, wait for your chip select to be asserted, and on each clock edge shift out the next bit of the current word. Check out [Pat]’s eminently readable code to see how simple it can be.

But that last little bit is where the complexity lies. When you’re the master it’s like being the apex predator, the king of the jungle, the head program manager. You dictate the tempo and everyone on the bus dances to the beat of your clock edge. Sure the datasheet for that SRAM says it can’t run faster than 8 MHz but do you really believe it? Not until you try driving that clock a little quicker to see if there’s not a speedier transfer to be had! When you’re the slave you have to have a bit ready every clock edge. Period. Missing even a single bit due to, say, an errant print statement will trash the rest of transaction in ways which are hard to detect and recover from. And your slave code needs to be able to detect those problems in order to reset for the next transaction. Getting stuck waiting to send the 8th bit of a transaction that has ended won’t do.

Check out [Pat]’s very friendly post for a nice refresher on SPI and their discoveries working through the problems of building a SPI slave. There are some helpful tips about how to keep things responsive in a device performing other tasks.

Arduino Fights Fire With… Water?

January 8, 2019 by 3 Comments

We don’t think we’d want to trust our fire safety to a robot carrying a few ounces of water, but as a demonstration or science project, [Tinker Guru’s] firefighting robot was an entertaining answer to the question: “What do I do with that flame sensor that came in the big box of Arduino sensors I bought from China?” You can see a video of the device below.

You can see, it is a pretty standard two-wheel robot with the drive wheels to the rear and a skid plate up front. There are a flame sensor and a water pump up forward, as well. You can probably guess, the device notices a flame and rushes to squirt water on it.

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Portable Pi Teensy Thumboard

January 7, 2019 by 12 Comments

Even on the go, there is no substitute for a physical keyboard with buttons that move and click. Sure, you could solder a bunch of tactile switches to some perfboard, but how about going all out and making something robust as [Anthony DiGirolamo] did for his Teensy Thumboard. Everything is insertion-mount so it is an approachable project for anyone who knows the dangerous end of a soldering iron, and that also makes it easy to hack on.

Each pin of the Teensy has an adjacent empty hole tied to it for easy access, and the serial data pins are exposed at the top of the board. All the holes use standard 0.1″ (2.54mm) spacing. The I/O points used by the keyboard are labeled, and the rest of them can use the space under the controller where proto-board style holes add some extra space for an IMU or whatever sensors suit your slant.

Most impressive is the shell, which is freely available on Thingiverse, where you can also find a bill of materials with links to everything you will need in case you don’t have drawers full of those tactile switches.

If this looks familiar, you have probably seen the PocketCHIP, and it is no secret that this project is an homage to that versatile pocket computer. We appreciate this kind of love for PocketCHIP, especially since they are now a limited commodity.

All About Ham Satellites

January 7, 2019 by 32 Comments

How hard is it to build a ground station to communicate with people via a satellite? Probably not as hard as you think. [Modern Ham] has a new video that shows just how easy it can be. It turns out that a cheap Chinese radio is all you need on the radio side. You do, however, benefit from having a bit of an antenna.

It isn’t unusual for people interested in technology to also be interested in space. So it isn’t surprising that many ham radio operators have tied space into the hobby. Some do radio astronomy, others bounce signals off the moon or meteors. Still others have launched satellites, though perhaps that’s not totally accurate since as far as we know all ham radio satellites have hitched rides on commercial rockets rather than being launched by hams themselves. Still, designing and operating a ham radio station in space is no small feat, but it has been done many times with each generation of satellite becoming more and more sophisticated.

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