While addressable LED strips are all the rage, [Mike] from [mikeselectricstuff] has been working on an installation using the more basic two-wire strips that are simply controlled via PWM dimming. He’s recently figured out a tidy way to send sensor signals down these strips without adding any additional cabling.
The build uses 24 V LED tape, which consists of gangs of 6 LEDs in series with a forward voltage of 3V. Thus, these strips don’t even begin to light until approximately 18V is across them.
By adding a 15 V Zener diode and a resistor across the MOSFET which dims the LEDs, a voltage of around 9 V can be put across the LEDs without lighting them up when the MOSFET PWM dimmer is in its off phase. A PIC10F322 microcontroller and an accelerometer can then be run from this voltage, with the aid of a 3.3 V regulator wired in parallel with the LEDs. The regulator must also be able to handle the full 24 V when the LEDs are switched on.
A transistor is also wired up, switching a 2.2 K resistor in parallel with the LEDs. When turned on by the PIC, this transistor causes roughly a 10 mA current to flow through the Zener diode and its series resistor. The voltage developed across that series resistor can be measured as the transistor is turned on and off. In this case, the pulse width used to turn that transistor on is relative to motion detected by the accelerometer on the end of the LED strip.
Turning the LEDs on at 100% duty cycle prevents the system working, as the pulse widths generated by the sensor circuit can’t be detected when the LED line is held high all the time. However, in practice, it matters not — running the LEDs at a maximum 98% duty cycle eliminates the issue.
It’s an ingenious way to send sensor signals down a two-wire LED strip, even if it does take a second to wrap one’s head around it. It also seems to do a great job of adding motion-reactive effects to the LED strips in question. It’s not the first LED project we’ve seen from [Mike], either. Video after the break.
There’s more than one way to light up a strip of LEDs. Have you tried building your own hydroelectric power plant to do it? Well, now you can. Replicating [Matic Markovič]’s entry into the 2020 Hackaday Prize is bound to teach you something, if not many things, about the way hydroelectric power is generated and the way the variables play into it.
In [Matic]’s model, water from an adjustable-height reservoir flows into a 3D-printed Pelton turbine. The water jet hits the turbine’s cupped fins at a 90° angle, causing the assembly to spin around rapidly. This mechanical energy charges a brushless DC motor that’s connected to an Arduino Nano, which rectifies the AC from the generator and uses it to light up an RGB strip like an equalizer display that represents the power being generated.
This is easily one of the coolest educational displays we’ve ever seen. The reservoir can move up and down over a 55 cm (21.6″) range with the flick of a three-way toggle, which makes it easy to see that the higher the reservoir, the more power is generated. [Matic] has the STLs and INOs in the usual places if you want to make your own. Flow past the break for a demonstration, followed by an exploded render that gets put back together by invisible hands.
Resin 3D printers are finally cheap enough that peons like us can finally buy them without skipping too many meals, and what means we’re starting to see more and more of them in the hands of hackers. But to get good results you’ll also want a machine to cure the prints with UV light; an added expense compared to more traditional FDM printers. Of course you could always build one yourself to try and save some money.
To that end, [sjm4306] is working on a very impressive controller for all your homebrew UV curing needs. The device is designed to work with cheap UV strip lights that can easily be sourced online, and all you need to bring to the table is a suitable enclosure to install them in. Here he’s using a metal paint can with a lid to keep from burning his eyes out, but we imagine the good readers of Hackaday could come up with something slightly more substantial while still taking the necessary precautions to not cook the only set of eyes you’ll ever have.
Of course, the enclosure isn’t what this project is really about. The focus here is on a general purpose controller, and it looks like [sjm4306] has really gone the extra mile with this one. Using a common OLED display module, the controller provides a very concise and professional graphical user interface for setting parameters such as light intensity and cure time. While the part is cooking, there’s even a nice little progress bar which makes it easy to see how much time is left even if you’re across the room.
At this point we’ve seen a number of hacked together UV cure boxes, but many of them skip the controller and just run the lights full time. That’s fine for a quick and dirty build, but we think a controller like this one could help turn a simple hack into a proper tool.
A tiny toy train that [voidnill] illuminated with a small LED strip fragment demonstrates several challenges that come with both modifying existing products, and working with small things in general. One is that it is hard in general to work around existing design choices and materials when modifying something. The second is that problems are magnified with everything is so small.
[voidnill]’s plentiful photos illustrate everything from drilling out small rivets and tapping the holes for screws to installing a tiny switch, LED strip, and button cells as a power supply. When things are so small, some of the usual solutions don’t apply. For example, cyanoacrylate glue may seem like a good idea for mounting small plastic parts, but CA glue easily wicks into components like the tiny power switch and gums up the insides, rendering it useless.
[voidnill] uses lots of careful cutting and patience to get everything done, and demonstrates the importance of quality tools. The LED strip fragment is driven by three small button cells, and while tape does a serviceable job as a battery holder, [voidnill] believes a 3D printed custom frame for the cells would really do the trick.
Sometimes, a project turns out to be harder than expected at every turn and the plug gets pulled. That was the case with [Chris Fenton]’s efforts to gain insight into his curling game by adding sensors to monitor the movement of curling stones as well as the broom action. Luckily, [Chris] documented his efforts and provided us all with an opportunity to learn. After all, failure is (or should be) an excellent source of learning.
The first piece of hardware was intended to log curling stone motion and use it as a way to measure the performance of the sweepers. [Chris] wanted to stick a simple sensor brick made from a Teensy 3.0 and IMU to a stone and log all the motion-related data. The concept is straightforward, but in practice it wasn’t nearly as simple. The gyro, which measures angular velocity, did a good job of keeping track of the stone’s spin but the accelerometer was a different story. An accelerometer measures how much something is speeding up or slowing down, but it simply wasn’t able to properly sense the gentle and gradual changes in speed that the stone underwent as the ice ahead of it was swept or not swept. In theory a good idea, but in practice it ended up being the wrong tool for the job.
The other approach [Chris] attempted was to make a curling broom with a handle that lit up differently based on how hard one was sweeping. It wasn’t hard to put an LED strip on a broom and light it up based on a load sensor reading, but what ended up sinking this project was the need to do it in a way that didn’t interfere with the broom’s primary function and purpose. Even a mediocre curler applies extremely high forces to a broom when sweeping in a curling game, so not only do the electronics need to be extremely rugged, but the broom’s shaft needs to be able to withstand considerable force. The ideal shaft would be a clear and hollow plastic holding an LED strip with an attachment for the load sensor, but no plastic was up to the task. [Chris] made an aluminum-reinforced shaft, but even that only barely worked.
The great irony of the social media revolution is that it’s not very social at all. Users browse through people’s pictures in the middle of the night while laying in bed, and tap out their approval with all the emotion of clearing their spam folder. Many boast of hundreds or thousands of “friends”, but if push came to shove, they probably couldn’t remember when they had last seen even a fraction of those people in the real world. Assuming they’ve even met them before in the first place. It’s the dystopian future we were all warned about, albeit a lot more colorful than we expected.
Every social action requires that a specific and deliberate physical interaction be performed, which have largely been designed to mimic normal human contact. A pat on the shoulder signifies you want to follow the wearer, and adding them as a friend is as easy as giving a firm handshake. These interactions bring more weight to the decisions users make. For example, if somebody wants to remove you as a friend, they’ll need to muster up the courage to look you in the eye while they hit the button on your chest.
The jacket uses an Arduino to handle the low level functions, and a Raspberry Pi to not only provide the slick visuals of the touch screen display, but record video from the front and rear integrated cameras. That way you’ve even got video of the person who liked or disliked you. As you might expect, there’s a considerable energy requirement for this much hardware, but with a 5200 mAh LiPo battery in the pocket [Tuang] says she’s able to get a run time of 3 to 4 hours.
Considering how much gadgetry is packed into it, the whole thing looks remarkably wearable. We wouldn’t say it’s a practical piece of outerwear when fully decked out, but most of the electronic components can be removed if you feel like going low-key. [Tuang] also points out that for a garment to be functional it really needs to be washable as well, so being able to easily strip off the sensitive components was always an important part of the design in her mind.
Typically when we hear the words “LED” and “Cube”, we think of small blinking devices on protoboard designed to flex one’s programming and soldering skills. However, while [Heliox]’s Cube Infini could be described as “a cube of LEDs”, it’s rather a different beast (video in French, subtitles available).
The cube starts with a 3D printed frame, designed in Fusion 360. The devil really is in the details — [Heliox] puts in nice touches, such as the artistic cube relief on the base, and the smart integrated cable management in the edges. The faces of the cube are plexiglass sheets, covered with a one-way reflective film that is applied in a similar manner to automotive window tint. For lighting, a high-density LED strip is fitted to the inside edges, chosen for maximum visual effect. It’s controlled by an IR remote and a cheap control module from Amazon.
While the build contains no particularly advanced tools, materials, or techniques, the final result is absolutely stunning. It’s a piece we’d love to have as a lamp in a stylish loungeroom or study. [Heliox] does a great job of explaining how the cube is designed and fits together, and it’s a testament to just what can be achieved with a little ingenuity and hard work.