FoTW: LED Strips Make Awful Servo Drivers

We must all have at some time or another spotted a hack that seems like an incredible idea and which just has to be tried, but turns out to have been stretching the bounds of what is possible just a little too far. A chunk of our time has disappeared without trace, and we sheepishly end up buying the proper part for the job in hand.

[Orionrobots] had a conversation with a YouTube follower about LED strips. An LED strip contains a length of ready-made PWM drivers, they mused. Wouldn’t it be great then, if each of the drivers on a strip could be connected to a servo, making the strip a ready-made single-stop SPI servo driver. With a large multi-servo robot to build, he set to work on a strip of WS2801s.

If you are in the Soldering Zone and have elite skills at the iron, then soldering a wire to a surface mount driver chip is something entirely possible. For mere mortals though it’s a bit of a challenge, and he notes just how much extra time it’s added to the project. The fun starts though when the servo is hooked up, the best that can be said is that it vibrates a bit. On paper, the LED drivers should be able to drive a servo, because they can create the correct waveform. But in practice the servo is designed to accept a logic level input while the driver is designed to sit in series with an LED and control its current. In practice therefore the voltages required for a logic transition can’t quite be achieved.

He concludes by recommending that viewers splash out on a servo driver board rather than trying an LED strip. We applaud him for the effort, after all it’s a hack any of us might have thought of trying for ourselves.

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Heads-Up Display Turns Car Into Fighter Jet

While most of us will never set foot in a fighter jet, some of us can still try to get as close as possible. One of the most eye-catching features of a fighter jet (at least from the pilot’s point-of-view) is the heads-up display, so that’s exactly what [Frank] decided to build into his car to give it that touch of fighter jet style.

Heads-up displays use the small reflectivity of a transparent surface to work. In this case, [Frank] uses an LED strip placed on the dashboard to shine up into the windshield. A small amount of light is reflected back to the driver which is able to communicate vehicle statues without obscuring view of the road. [Frank]’s system is able to display information reported over the CAN bus, including voltage, engine RPM, and speed.

This display seems to account for all the issues we could think up. It automatically cycles through modes depending on driving style (revving the engine at a stoplight switches it to engine RPM mode, for example), the LEDs automatically dim at night to avoid blinding the driver, and it interfaces with the CAN bus which means the ability to display any other information in the future should be relatively straightforward. [Frank] does note some rough edges, though, namely with the power supply and the fact that there’s a large amount of data on the CAN bus that the Teensy microcontroller has a hard time sorting out.

That being said, the build is well polished and definitely adds a fighter jet quality to the car. And if [Frank] ever wants even more aviation cred for his ground transportation, he should be able to make use of a 747 controller for something on the dashboard, too.

Watch the ClearWalker Light Up and Dip Its Toes

[Jeremy Cook]’s latest take on the Strandbeest, the ClearWalker, is ready to roll! He’s been at work on this project for a while, and walks us through the electronics and control system as well as final assembly tweaks. The ClearWalker is fully controllable and includes a pan and tilt camera as well as programmable LED segments, and even a tail.

When we last saw [Jeremy] at work on this design, it wasn’t yet functional. He showed us all the important design and assembly details that went into creating a motorized polycarbonate version of [Theo Jansen’s] classic Strandbeest design; there’s far more to the process than simply scaling parts up or down. Happily, [Jeremy] is able to show off the crystal clear beauty in his photo gallery as well as a new video, embedded below.

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Want To Wake Up In A Ship’s Warp Core? Circadia Sunrise Clock Makes it So

Who among you has difficulty rising in the mornings? Sunrise clocks that simulate a — well, sunrise,  are a gentle means of returning to the waking world. [FlorianH], grappling with this very issue, has built his own impressive sunrise clock he has named Circadia. Some sunrise clocks mate an LED with a dev board and call it a day. This work of hardware art will never be confused for something rudimentary.

Standing at 187cm tall, the 8mm thick PCB frame contains three main sections that plug into each other “like Lego”: the top houses a cleverly designed (and virtually silent) propeller clock and a speaker with a 3D-printed, omni-directional reflector. The midsection is reinforced with an MDF column, around which is wrapped 16 strips of 18 RGB LEDs with a heat-molded sheet of acrylic to diffuse the light, while the bottom section has the mid-woofer, the Raspberry Pi 2 brain, most of the electronics, and three switched power supplies.

Built over two years, the primary feature is a variety of themes — with more being added all the time — ranging from rain forest, to arctic, to the warp core of a starship that will rouse you over the course of a half hour. Circadia can also function as a visualizer during a party, or even a Tetris display (a theme that was designed and tested in an afternoon!). Seeing it in action is a treat:

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Cityscape Infinity Table

Redditor [ squishy0eye] lacked a coffee table and wanted an infinity mirror. So, in a keen combination of the two, she built an infinity mirror table the resembles a nighttime cityscape.

Skimming over many of table’s build details, [squishy0eye] paused to inform the reader that an MDF base was used underneath the mirrors, with a hole drilled for the future power cable. For the top pane, she overlaid privacy screen mirror film onto tempered glass, turning it into a one-way mirror. The bottom pane is acrylic plastic due to the need to drill holes to hide the cables for each ‘building’ — the same mirror film was applied here as well. Wood was cut into rectangles for the building shapes and super glued around the holes and in the corresponding spots underneath to prevent any bowing in the acrylic. A small gap was left in each ‘building’ to run the 5050 non-waterproof LED strips around and back into the hole for power.

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LED Notification Cube is a Good First Project

Two years ago, [Matt] made a move away from his software hacks and into the physical world. He was part of a pilot program to provide mentorship to children as part of the Maker Education Initiative. This program gave him access to 3D printers, CNC machines, and laser cutters within the New York Hall of Science makerspace. [Matt] chose to build an illuminated notification cube for his first physical project. The idea being that smart phones have so many alerts, many of which are unimportant. His project would help him to visualize and categorize each alert to better understand its importance.

The brain of the system is a Raspberry Pi. [Matt] found a Python library that allowed him to directly control an RGB LED strip based on the LPD8806 chip. He wired the data pins directly to the Pi and used an old 5V cell phone charger to power the LEDs. The strip was cut into smaller strands. Each face of the cube would end up with three strands of two LEDs each, or six LEDs per side. [Matt] found a mount for the Pi on Thingiverse and used a 3D printer to bring it into existence. The sides were made of frosted laser cut acrylic. The frosted look helps to diffuse the light from the LEDs.

Over time [Matt] found that the cube wasn’t as useful as he originally thought it would be. He just didn’t have enough alerts to justify the need. He ended up reprogramming the Pi to pull weather information instead, making use of the exact same hardware for another, more useful purpose.

LEDs Strips Tell You the Trains Aren’t Running

[James] is a frequent user of the London Underground, a subway system that is not immune to breakdowns and delays. He wanted a way to easily tell if any of the trains were being disrupted, and thanks to some LEDs, he now has that information available at a glance without having to check a webpage first.

Inspired by the Blinky Tape project at FT Engineering, [James] thought he could use the same strip of addressable LEDs to display information about the tube. A Raspberry Pi B+ gathers data from the London Underground’s TfL API and does a few calculations on the data. If there is a delay, the LEDs in the corresponding section of the strip will pulse, alerting the user to a problem with just a passing glance.

The project is one of many that displays data about the conditions you’ll find when you step outside the house, without having to look at a computer or smartphone. We recently featured an artistic lamp which displays weather forecasts for 12 hours into the future, and there was an umbrella stand which did the same thing. A lot is possible with LEDs and a good API!

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