[Mukesh Sankhla] writes in to share this unique weather display that looks to be equal parts art and science. Rather than show the current conditions with something as pedestrian as numbers, this device communicates various weather conditions to the user with 25 WS2812B LEDs embedded into the 3D printed structure. It also doubles as a functional planter for your desk.
So how does this potted plant tell you if it’s time to get your umbrella? Using a NodeMCU ESP8266 development board, it connects to openweathermap.org and gets the current conditions for your location. Relative temperature is conveyed by changing the color of the pot itself; going from blue to red as things heat up. If there’s rain, the cloud over the plant will change color and flash to indicate thunder.
[Mukesh] has made all of the STL files for the printed components available, as well as the source code for the ESP8266. You’ll need to provide your own soil and plant though, there’s only so much you can send over the Internet. Incidentally, if the clever way he soldered these WS2812B modules together in the video catches your eye, you’ll really love his “RGB Goggles” project that we covered earlier.
For his final project in UCLA’s Physics 4AL program, [Timothy Kanarsky] used a NodeMCU to smarten up a carefully dissected NERF football. With the addition to dual MPU6050 digital accelerometers and some math, the ball can calculate things like the distance traveled and angular velocity. With a 9 V alkaline battery and a voltage regulator board along for the ride it seems like a lot of weight to toss around; but of course nobody on the Hackaday payroll has thrown a ball in quite some time, so we’re probably not the best judge of such things.
Even if you’re not particularly interested in refining your throw, there’s a lot of fascinating science going on in this project; complete with fancy-looking equations to make you remember just how poorly you did back in math class.
As [Timothy] explains in the write-up, the math used to find velocity and distance traveled with just two accelerometers is not unlike the sort of dead-reckoning used in intercontinental ballistic missiles (ICBMs). Since we’ve already seen model rockets with their own silos, seems all the pieces are falling into place.
The NodeMCU polls the accelerometers every 5 milliseconds, and displays the data on web page complete with scrolling graphs of acceleration and angular velocity. When the button on the rear of the ball is pressed, the data is instead saved to basic Comma Separated Values (CSV) file that’s served up to clients with a minimal FTP server. We might not know much about sportsball, but we definitely like the idea of a file server we can throw at people.
There was a time when you could hold onto a TV or A/V receiver for the better part of the decade and not feel as though you were missing out on the latest and greatest features. But today you’re lucky to get three years out of a “smart” TV before it’s either supplanted by a vastly improved version, or falls victim to some weird issue that (surprise, surprise) means you need to buy a new one.
Not content with the status quo of planned obsolescence, [aamarioneta] recently set out to add a sprinkling of modern convenience to a circa 2008 Denon AVR 2308 home theater receiver. Like any good A/V receiver, the AVR 2308 features a dizzying array of ports on the back panel, one of which happens to be for an external infrared receiver. This turned out to be the perfect place to jack in an ESP8266, earning this 12 year old receiver an honorary membership into the Internet of Things.
The interesting thing about this hack is that there’s actually no IR involved. Sure, the code could be used to drive an IR LED attached to the ESP8266’s GPIO pins, and the AVR 2308 would respond as if the original remote was being used; but where’s the fun in that? Thanks to the receiver port, they’re able to inject the IR codes directly into the device. It’s the same protocol, just without the photons.
With a simple web-interface running on the ESP8266, they can control the AVR 2308 from a smartphone’s browser anywhere in the house. From here it would only take a few more lines of code to tie it into an existing home automation system or add in support for Alexa voice control.
Over the last few years, the price of a good digital picture frame has dropped to the point that we don’t often see DIY versions anymore. As much as we might hate to admit it, it’s hard to justify building something yourself when the economies of scale have made it so you can buy the final product for less than the cost of the parts themselves. But of course, there are always fringe cases where building it might be the only way to get what you need.
Granted we’re not sure that [Tony Liu] actually needs a 1.8-inch digital picture frame, but we’re sure somebody out there does. The ST7735R display used in this project is a real TFT, so the color and refresh rate is pretty good; but with a resolution of just 128×160, we’d recommend keeping your expectations low in regards to visual fidelity.
What’s really interesting about this project is how low the part count is. All you need is the ST7735R display and the ESP8266 itself (or the development board of your choice, naturally). Even the 3D printed frame is technically optional. The display is driven by SPI, so with the power added in, that’s only eight wires that need to be soldered between the two devices. If you’re looking for an easy way to add a photo slideshow to a small device, say a conference badge, this is about as easy as it gets.
But where are the images coming from? You might think SPIFFS, but in this case [Tony] has converted the images to bitmaps and is loading them into the Arduino Sketch as a header file with PROGMEM. Helpfully, he provides the link for the tool he uses to convert the images into an array the graphics library can understand. This makes adding new images slightly time consuming, but we imagine if you have the need for something like this, it’s probably only showing a pretty specific set of images anyway.
Those of us who have not been in that position can only imagine the anguish of learning that your teenager has cancer. This happened to [Rob], whose child was diagnosed with papillary thyroid cancer. It’s a condition that can be treated with surgery followed by a course of radioactive iodine to kill any remaining cancer cells. During iodine treatment, the patient is radioactive enough that other people must maintain a distance of 3m from them, and as a learning exercise for both father and teen he created and refined the design of a portable wireless radioactivity monitor.
There are a variety of sensors for radiation monitoring including the well-known Geiger–Müller tube, but he settled on a PIN photodiode based sensor supplied by radiation-watch.org. This sensor is not at its most sensitive at the energy levels emitted by the iodine isotope used in the treatment, but the relatively high intensity of the radiation meant that enough would register for a useful reading to be taken. The sensor board he was mated to an ESP8266 module. [Rob] went through three iterations of the balance of the hardware before settling on a lithium-ion battery and a plastic case.
On the software side, the ESP connects to an MQTT server, from which a CSV file of data is derived. On a computer, the CSV data is collected and plotted to a graph. The data take during treatment clearly shows the reduction in radiation following the isotope’s half-life. The graph isn’t perfect though, there is a gap due to the second prototype’s batteries running flat
From his epilogue it appears that his son has recovered, and we wish them further good health. The details have been published in the hope that other young people facing the same trial might benefit from building their own radiation monitor.
There are times when a sensor is required that does its job without the need for human attention over a long period, and for those applications a minimal power drain is a must. [Dave Davenport] had an EPS8266-based moisture sensor, and became disappointed in having to replace its AA batteries every few months. With an 18650 Li-ion cell and a bunch of power-saving tricks that time has been extended so far to over a year and still going, so he’s written a blog post detailing how he did it.
Some of his techniques such as turning off the sensor or using a better LDO regulator than the stock Wemos one are straightforward. Others though are unexpected, such as using the memory associated with the on-board RTC to store the WiFi connection info and channel number during sleep. The normal ESP8266 connection sequence involves a network scan, by hanging onto what it found last time the extra time and thus power expended by it can be avoided. Similarly switching from a DHCP lease to a fixed IP address cuts the time the device waits for a lease and thus the time it has to stay awake.
The ability to get professionally manufactured PCBs, at least small ones, for dirt cheap has had a huge impact on the sort of projects we see around these parts. It’s getting to the point where experimenting with PCB enclosures is not only a way to make your next project stand out, but an economical choice.
Which is how this ESP8266 sensor gadget from [Josef Adamčík] got its unique “folded over” look. The top panel is where the microcontroller and headers for various sensors live, the bottom panel is home to the TP4056 USB charging module, and the center panel provides mechanical support as well as holds the single 18650 cell. Rather than close the whole thing up with a fourth panel, he decided to leave it open so the battery can easily be removed. Plus, of course, it looks cooler this way.
Could [Josef] have fit all his electronics on a single 100 x 100 PCB and then put the whole thing into a 3D printed enclosure? Well, sure. But that’s been done to death at this point, and besides, he was looking for an excuse to get more comfortable doing PCB design. We think it also makes for a considerably more visual appealing final product than simply taking the “normal” way out.
Currently [Josef] has an SHT21 humidity/temperature sensor and a BH1750 light sensor slotted into the headers on the top side of the device, but they could just as easily be swapped out with something else if you wanted to do something a bit more exciting. We notice that homebrew air quality monitors are becoming increasingly popular.