All things considered, it’s pretty easy to get one LED is a strip to light up sequentially, and have it bounce back and forth. Turning that simple animation into a real Larson scanner, with smooth transitions and controlled fade-out, is another thing entirely. And forgetting the LEDs altogether and making a servo-operated Larson scanner is — well, let’s just call it an interesting lesson in hardware abstraction.
The Larson scanner, named after famed TV producer Glen A. Larson for his penchant for incorporating it into shows like Battlestar Galactica and Knight Rider, is actually hard to execute in hardware thanks to the fading tail that follows the lead pixel as it dances back and forth across the display. [Eric Gunnerson] decided to make this and other animation effects easier to achieve with Fade, a custom framework for LED animations that runs on an ESP32.
LED animations are fine, but what about servos? Could Fade be modified to support them? This turned out to be a fairly easy mod thanks to Fade’s architecture and [Eric]’s existing support for non-addressable LEDs via PWM signals. And it was even possible to support more than the 16 PWM channels on an ESP32by adding a UDP connection that puts multiple ESP32s under the control of a central microcontroller.
The video below shows [Eric]’s demo of servo support, with an eight-channel electromechanical Larson scanner. Each “pixel” is a painted ping pong ball swinging back and forth on a hobby servo, and the whole thing sounds just about as awful as you’d expect it to. If you squint just right, the effect looks pretty convincing, but that’s hardly the point. The real story here is [Eric]’s thoughtful architecture, which made the mods easier than starting from scratch.
Continue reading “No LEDs Required For This Servo-Controlled Larson Scanner” →
Hasselhoff make Larson Scanners famous. That’s the name for the scanning red lights on the front of KITT, the hero car from the popular 1980s TV series Knight Rider. Despite serving a solely aesthetic role, they remain a fun and popular LED project to this day. Putting a new twist on the old concept, [Pete Prodoehl] whipped up a Larson Scanner that you crank to operate.
Built out of LEGO, the project relies on a hand crank to work. The crank turns a drum, onto which is placed several strips of conductive Maker Tape – a steel/nylon material which we’ve looked at before. Strips of tape running side-by-side are bridge by segments of tape on the drum as it turns. The LEDs are switched on in the requisite pattern of a traditional Larson scanner.
The project has inspired further possibilities, such as using similar techniques to produce an electronic music box or player piano that will change tempo as the user changes the speed with the crank. [Pete] notes that turning the crank is an inherently enjoyable experience, and given the wonder inherent in hand-cranked musical projects like Marble Machine X, we can’t wait to see where this one goes next. Video after the break.
Continue reading “Manual Larson Scanner Invites You To Crank It” →
What to call this LED strip music visualizer is a puzzler. It lights up and pulsates in time with music similar to the light organs of 1970s psychedelia fame, but it’s more than that. Is it more like the Larson Scanner that graced the front of [David Hasselhoff]’s ride on Knight Rider? A little, but not quite.
Whatever you decide to call this thing, it looks pretty cool, and [Scott Lawson] provides not one but two ways to build it. The business end is a simple strip of WS2812b addressable LEDs. It looks like the first incarnation of the project had an ESP8266 driving the LEDs in response to commands sent to it from a PC running the visualization code, written in Python. That setup keeps the computationally intensive visualization code separate from the display, but limits the display to 256 pixels and probably has to deal with network latency. The Raspberry Pi version both crunches the numbers and drives the display, but the Pi doesn’t have the oomph to run both the LEDs and the GUI, which is pretty interesting to look at by itself. The video below shows the different visualization modes available — we’re partial to the “energy effect” at the end.
Take your pick of hardware and throw a couple of these things together for your next rave. And if you need a little more background on the aforementioned Larson Scanner, we’ve got you covered.
Continue reading “LED Strip Display Gives You Two Ways To See The Music” →
[Glen A. Larson] passed away on Friday at the age of 77. He may be most widely recognized for being a producer of the original Battlestar Galactica, Magnum, P.I. and Knight Rider television series’. But for us his association with a row of LEDs which illuminates in a back and forth pattern will always be his legacy.
When we heard about his passing we figured that we would hear about his invention of the Larson Scanner but that was not the case. A bit of research turned up a pretty interesting Wikipedia bio page. He has origins in a music group call The Four Preps and actually composed or collaborated on a number of television theme songs among other notable accomplishments. But nothing about electronics. Did this man of many hats actually invent the hardware for the Larson Scanner used as the Cylon Eye and on the front of K.I.T.T., or does it simply share his name?
Evil Mad Scientist Labs claims to have coined the term Larson Scanner. [Lenore Edman] confirmed to us that EMSL did indeed start the term which is used to name their electronics kit and directed us to [Andrew Probert] who lists effects for the TV series on his portfolio. We’ve reached out to him for more information but had not heard back at the time of publishing. We’ll update this post as details emerge. In the mean time, if you have any insight please leave it below including the source of the information.
If you are not aware, a Larson Scanner is so interesting because the pattern calls for a fading trail of LEDs. It is not simply a fully illuminated pixel moving back and forth but includes dimmed pixels after the brightest one has passed. This is an excellent programming challenge for those just getting into embedded development.
Those interested in learning more about [Gary] may find this lengthy video interview of interest. Otherwise it’s time for the collection of links to past Larson Scanner projects which we’ve covered.
This hulking monument to illumination is [DJJules’s] 6-foot-long Ultimate Larson Scanner. If you’re scratching your head in confusion, the Larson Scanner is the ever-popular scrolling LEDs seen on KITT (the car) from Knight Rider and on Cylons in Battlestar Galactica (1978), named after the creator of the series.
[DJJules’s] iteration consists of sixteen 10W LEDs, each mounted on a heat sink which bolt on to a 6′ long piece of angle aluminum sourced from a local hardware store. He used a basic MOSFET constant current driver for each LED, attaching the MOSFETS to the heat sink with 4-40 screws. Each LED module then connects to a TLC5940 LED driver breakout board from Sparkfun, which plugs into an Arduino Pro Mini.
Check out the Instructables page for the source code and other important details, including safely powering the build (the LEDs can draw around 1A each), then grab your sunglasses and stick around for a quick video below.
Continue reading “A Blindingly Bright Larson Scanner” →
[Kevin] undertook a robot build partly for his own enjoyment, but also to include his kids in the action. He acquired a cheap toy and packed it full of programmable goodness. The starting point was a $15 toy called Rad 2.0. It’s a great starting point as it already included some motorized parts, and takes care of much of the mechanical issues like joints and structure.
The image on the left is the fourth update which [Kevin] has posted. The robot now responds to voice commands (with the same syntax as Chippu uses), moving its gaze to face forward or to either side. You’ll notice there’s a wireless webcam which lets him spy on what’s in front of the robot’s gaze. An ultrasonic range finder makes itself at home in the beak of the bot, and a Larson Scanner is nestled in the brow using the kit from Evil Mad Scientist Labs. Check out the video after the break for an overview of the hardware modifications.
The build log for this project is a forum post. That forum is run by [DJ Sures], a veteran at taking cheap toys and making them awesome. It seems like he’s taken a web forum and made it awesome too because the conversation about [Kevin’s] project is packed with constructive tips and encouragement.
Continue reading “$15 Toy Becomes Fully Programmable Robot” →
[Andrea] built this LED chaser using one logic chip. It illuminates all but one of the six LEDs, with the dim bit moving back and forth along the row in a chase sequence. This is something like an inverse Larson Scanner without the fading tail. But doing it with a logic chip instead of a microcontroller is a fun challenge.
Which brings us to the point of this feature. [Andrea] didn’t really post an explanation of how the circuit works. Usually missing details mean that we archive the tip and move on to the next one, but we think this provides a fun activity. Can you figure out how the circuit works? We already know that it’s using a CD4017 decade counter/divider chip. This gets its clock signal from a 555 timer circuit. [Andrea’s] schematic is a bit hard to read, but grab a copy, blow it up a bit (or use your browser zoom) and study the CD4017 datasheet (PDF) if you need to.
Want proof that it does actually work? It’s embedded after the break.
Continue reading “Challenge: Figure Out How This Logic-based Chaser Works” →