Anyone who has done anything with RGB LEDs knows that their ability to display pretty much any color is somehow both the best and worst thing about them. How do you get it right? How do you make your results repeatable? [Thomas] has the answer. He dug around in the ol’ parts cupboard, found a few pots, and got to work making this stay-home stew of a project — an on-demand RGB LED color mixer.
Three cleverly color-coded potentiometers and an Arduino let [Thomas] step through 0-255 to mix various values of red, blue, and green. The shade that gets made is displayed live on a set of 10 individual NeoPixels that are laid out under a frosty diffusing panel. Each of the RGB values are also shown on an 16×2 LCD.
This is one of those projects that hits a sweet spot of being simple, useful, and fun. It’s even nice-looking and compact. What more could you want from a project cobbled together from ingredients on hand? [Thomas] is even giving away the code recipe.
All the balls are connected together with some clever 3D printed pieces that were inspired by the classic soccer ball layout of hexagons and pentagons. [thomasj152] chose this shape because it’s fairly easy to code animation sequences for it.
The design also breaks down nicely into two halves, which makes it easier to wire. All 80 of the balls are controlled with a single NodeMCU ESP8266 development board.
This stranded version is the second lamp [thomasj152] built. The first one used the same soccer ball style, but had RGB LED strips instead, and the balls were wrangled with laser-cut support pieces. Strips lay much flatter than strands do, leaving the inside tidy and spacious. Unfortunately, the LED strips got fried accidentally, which is extra sad because the strips version looks like way more work.
The bright spot here is that [thomasj152] can now provide instructions for both versions. He even has code that cycles through each pentagon and hexagon section, lighting them up one at a time for testing and sanity checks. Roll past the break for a walk-through video that shows both versions and explains the differences.
When it comes to keeping abreast of the COVID-19 pandemic, there are basically two schools of thought. Some people would rather not hear the number of confirmed cases or deaths, and just want to focus on those who recovered. That’s fair enough. But others want to have all of the available data at their disposal so they can form their own conclusions about what’s happening with this virus on a global scale. Looking at this incredible COVID-19 status board, we’ll give you one guess which category [Reuben] falls into.
Note the laser engraved component labels
Constructed out of 2020 extrusion with both 3D printed and laser cut parts, this wall-mounted display is built to last. Clearly [Reuben] believes we’re in this one for the long haul, and taking a peek at the plethora of data points this device can show at once, it’s not hard to see why.
Stats are pulled down every hour from a JSON API by an ESP32 and stored on an SD card. A running total of confirmed cases, deaths, and recoveries are shown on several TFT displays located behind the face of the display. On the right, the relative severity of the infection in 32 different countries is visualized with LEDs of varying brightness.
Perhaps the most visually striking element of the display is the large annunciator panel on the left side, which lights up to show various conditions all over the world. We appreciate that [Reuben] has thought ahead and added a light that can be used once a vaccine is deployed for COVID-19, but the inclusion of a “MARTIAL LAW” indicator certainly doesn’t help us shake the feeling we’ve all found ourselves in a proper dystopia.
LED jewelry has always been a popular part of the maker community. Oftentimes, coin cells are used as a compact source of power, or wires are run to discreet hidden battery packs. [OguzC3] went another route, however, creating a glowing ring which works as its own battery.
The design will be familiar to those who have done high-school experiments on basic batteries. An aluminium pipe forms the inner surface of the ring, which is then wrapped in a layer of newspaper. A copper outer ring is then placed outside. When soaked in a salt water solution, this forms a basic battery. The voltage output is only around 0.5 volts, so a joule thief circuit is built into the ring to step this up high enough to drive an LED. [OguzC3] reports that the ring lasts several hours at a time, and only needs a quick rinse in fresh salty water to recharge.
The outer shell was created by first starting with a 3D printed heart shape. This was used as a form upon which the brass wire could be soldered together to form an attractive heart-shaped cage. Inside, an Arduino Nano is hooked up to a series of WS2812b LEDs. The LEDs are flashed in time with the heartbeat of the person holding the heart, thanks to a MAX30102 heartbeat sensor. There’s also a TP4056 charge module and a small lithium battery to provide power for the device.
Adding the heartbeat sensor really makes this project shine, forming a connection between the holder and the device itself. The tasteful craftsmanship of the brass design makes this an excellent gift, one we’re sure anyone would like to receive. We’ve seen [Jiří Praus] make the most of this artform before too, with projects like this stunning tulip or dead-bug Arduino. Video after the break. Continue reading “LED Heart Beats With The Beholder”→
[hclxing] eagerly picked up an LED ceiling light for its ability to be turned on and off remotely, but it turns out that the lamp has quite a few other features. These include adjustable brightness, color temperature, automatic turnoff, light sensing, motion sensing, and more. Before installing, [hclxing] decided to tear it down to see what was involved in bringing all those features to bear, but after opening the lamp there wasn’t much to see. Surprisingly, besides a PCB laden with LEDs, there were exactly two components inside the unit: an AC power adapter and a small white controller unit. That’s it.
Microwave-based motion sensor board on top, controller board for LED ceiling light underneath.
The power adapter is straightforward in that it accepts 100-240 Volts AC and turns it into 30-40 Volts DC for the LEDs, and it appears to provide 5 V for the controller as well. But [hclxing] noticed that the small white controller unit — the only other component besides the LEDs — had an FCC ID on it. A quick bit of online sleuthing revealed that ID is attached to a microwave sensor module. Most of us would probably expect to see a PIR sensor, but this light is motion sensing with microwaves. We have seen such units tested in the past, which links to a video [hclxing] also references.
The microwave motion sensor board is shown here, and underneath it is a dense PCB that controls all other functions. Once [hclxing] identified the wires and their signals, it was off to Costco to buy more because the device looks eminently hackable. We’re sure [hclxing] can do it, given their past history with reverse-engineering WyzeSense hardware.
Looking to sterilize something? Give it a good blast of the old UV-C. Ultraviolet radiation in the shortest wavelength band breaks down DNA and RNA, so it’s a great way to kill off any nasties that are lurking. But how much UV-C are you using? [Akiba] at Hackerfarm has come up with the NukeMeter, a meter that measures the output of their UV-C sterilizer the NukeBox. It is built around a $2.50 sensor and a $3 Arduino.
