When [hkdcsf] was a teenager, he made a Christmas star with an up counter driving decoder logic and using transistors to light LEDs in festive patterns. He’s revisited this project using modern techniques including a microcontroller, a DC/DC converter, and constant current LED drivers.
The project uses two AA batteries, and that’s what makes the DC/DC converter necessary. Blue LEDs have a forward voltage of just over 3V, and the LED driver chip requires about 0.6V of overhead. Two fresh AAs will run a tad above 3V, but as they discharge, or if he’s using rechargeables, there just won’t be enough potential. To make sure the star works even with whatever LEDs are chosen, the converter takes the nominal 3V from the batteries and converts it to 3.71V.
Continue reading “Christmas Star uses Two AA Batteries”
What do you get when you take a massive number of LEDs and combine them with a shopping cart and a bicycle? An awesome rave-mobile created by [kramerr]. He’s even taking it one step further by making the electronics solar powered.
[Kramerr] controls the LEDs with multiple WS2803 LED drivers. Three PIC18F4550s control the WS2803s over SPI. He devised a neat way of exciting the LEDs from music by using a pair of graphic equalizer display filter chips, MSGEQ7s, to drive the PICs to create patterns. A USB input also allows the PICs to display song titles or other information.
The mechanical design is as impressive as the electronics. The rear half of a bicycle is welded to the frame of the shopping cart with the cart’s handle used for steering. The shopping cart’s rear wheels are replaced by small bicycle wheels.
But [Kramerr] wasn’t done. He built his own solar panel since he couldn’t find one to fit the size requirements. The panel consists of 26 cells connected in series to provide 1A at 13V on a sunny day. A solar charge controller keeps a standard 12v lead acid battery ready to power the tricycle cart.
And there is still more! There is a sound system driven by a Raspberry Pi. The Pi also drives the USB inputs when [Krameer] wants to display song titles or artists instead of the audio patterns.
There are at least four hacks in this project each worthy of applause. [Karmeer] deserves an ovation for doing all of them in one project. If you are looking for less bling and less pedaling may we direct you to this powered, riding shopping cart.
Some rave music and lights via video after the break.
Continue reading “A Sound and LED-tastic Tricycle Shopping Cart”
Long-time Hackaday reader [Andrew Rossignol] bought a Boosted-brand electric skateboard while he was living in NYC. While the batteries more than sufficed for his commute in the Big Apple, he ran out of juice when he moved to the Left Coast, leaving him three miles short of a ten mile trip.
Faced with the unthinkable fate of pushing his skateboard like a Neanderthal, [Andrew] added more batteries. There’s great detail about how he chose the battery chemistry and the particulars of charging and something about load balancing, so it’s definitely worth a read if you’re building an electric vehicle.
But once [Andrew] had some surplus battery capacity on board (tee hee!) he thought of ways to waste it. The natural solution: tons of RGB LED underlighting.
Still not content with an off-the-shelf solution (which wouldn’t let him recharge the batteries without unplugging the lights), he ended up rolling his own with an Arduino and some WS2812s. The nicest touch? Keeping it all out of the elements in a sweet aluminum box, hiding the cable salad within.
There’s a lot to be said for the good industrial design of something like the Boosted skateboard, but if you’d rather DIY, we’ve been covering electric skateboard for a while now. It’s nice to see how battery and motor technology have changed since then, too. Compare and contrast this recent build with that old-school version and with [Andrew’s] build that was covered in this post. We live in good times.
In a well documented blog entry, [Loren Bufanu] presents a project that lit up a glass dance floor covering a swimming pool with RGB strips. We mentioned a video of his project in a Hackaday links but didn’t have any background information. Now we do.
The project took around 450 meters of RGB strips controlled by two Rainbowduinos and driven by sixty-four power Mosfets, sixty-four bipolar transistors, and a few other components. Producing white light from the LEDs draws 8 amps from the power supply.
The Rainbowduino is an ATmega328 Arduino compatible board with two MY9221 controllers. Each controller handles 12 channels of Adaptive Pulse Density Modulation. In other words, it makes the LEDs flash nicely. [Loren] used the Rainbowduino instead of some alternatives because multiple R’duinos can coordinate their activities over I2C.
The software part of the project did not work as well as the hardware. The light patterns were supposed to follow the music being played. A PC software package intended to drive the R’duinos produced just a muddy mess. Some kludges, including screen captures (!), driven by a batch file tamed the unruliness.
It’s been awhile, but a similar disco dance floor, built by [Chris Williamson] but not over a pool, previously caught our attention. [Chris] is a principle in Terror Tech that recently got a mention on Sparkfun.
The video after the break fortunately does not make a big splash, but is still electrifying.
Continue reading “Swimming Pool Dance Floor Enlightened With Leds”
Hero-Design wants you to make art at work with this mesmerizing contraption and as far as we’re concerned they hit the nail right on the head with the inclusion of LEDs, we’re whores for LEDs. The team over at Hero have come up with an interactive wall of 464 pixels that can be individually controlled to display any of the available colors simply by turning the circular pixel in either direction.
The design is quite elegant with a luxurious color scheme of black on black on black. Until you touch a knob or play an animation, that is. The large wall unit comes with a custom designed animation of your choice along with three other animations (and hopefully instructions to create your own animation from scratch). They have taken some precautions that we’re pleased to see: each pixel has redundant LEDs in the case that one goes out and if the worst happens and the redundant goes up in smoke not to worry, each pixel is easily replaceable due to its modular design.
Continue reading “Curb Office Productivity With Expensive LED Wall”
You have to admit [Dylan Rush’s] clock is a real swinger. Literally. You’ve seen the desk novelties where an arm with leds mounted on it sweeps out a message? [Dylan] did the same thing to make a clock but instead of drawing numbers, he actually draws an analog clock face. Y’know one of those round things with arms?
Behind the clock is an Arduino driving a MAX7219 LED controller. Using the MAX7219 was a challenge because it expects a grid of LEDs while the clock needs a linear array. [Dylan] used a line of individual LEDs wired to match what the controller wanted. A rotary encoder tells the processor the position of the arm so the Arduino sketch can determine which LEDs should be lit to show the time and clock face.
What’s even more amazing is [Dylan] created this before clocks became infamous.
Swing over to the video after the break.
Continue reading “LED Pendulum Pulses Out Clock Face”
LEDs are amazing things. As time marches on, they are being used in more and more lighting applications – everything from household bulbs to automotive headlights. But the push for smaller, cheaper, and brighter LEDs seems to have hit a snag for some of the less reputable manufactures.
Case in point, [bigclivedotcom] has been testing of some 100 Watt LEDs from eBay. When these LEDs work correctly, they put out a face-melting beam of light that you wouldn’t dare looking into (picture the scene from Raiders of the Lost Ark). They also have some unusual specs for an LED, like running on 30 Volts – and that’s a lot compared to the forward voltage of most LEDs at around 2.5 volts@20 mA.
So what gives? Well many of these high-wattage LEDs use a string of several LEDs in series. And as [bigclivedotcom] points out, this can be a real problem when a few of the LEDs begin to fail and act more like a low value resistor than a typical LED. In the videos after the break you can see [bigclivedotcom] test the LEDs to get a better look and what’s happening and why.
Continue reading “Why 100 Watt eBay LEDs Are Not Your Friends”