Color Light Painting With A 3D Printer

Light painting, or taking a few RGB LEDs, a camera with a long exposure, and turning the world into Tron, has been around for a while. We haven’t seen many people using their household CNC machines for the same effect. [ekaggrat] is the exception. He’s already used a 3D printer to do some light painting, and now he’s doing it in color.

This build is an extension of an earlier project we saw that used a white LED to draw pictures within the build volume of a delta printer. Just like the last time, [ekaggrat] wired LEDs up to a RAMPS board and toggled pins with the M42 command. This build merely triples the complexity of the wiring; the RGB LED is wired to pins 4,5, and 6 of the controller board, and the shutter release button of his camera is wired up to pin 11 with an optoisolator.

The ability to blink out Gcode is one thing, getting his two-year-old daughter to stand still for 3D scanning is another thing entirely. With the data in hand, [ekaggrat] was able to run this model through a script that would generate a light painting of his daughter. You can grab the script for that on GitHub, or check out the video below.

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Blinking LEDs For A Timeless Fountain

We’ve seen a few of these builds before, but the build quality of [Mathieu]’s timeless fountain makes for an excellent display of mechanical skill showing off the wonder of blinking LEDs.

This timeless fountain is something we’ve seen before, and the idea is actually pretty simple: put some LEDs next to a dripping faucet, time the LEDs to the rate at which the droplets fall, and you get a stroboscopic effect that makes tiny droplets of water appear to hover in mid-air.

Like earlier builds, [Mathieu] is using UV LEDs and is coloring the water with fluorescein, a UV reactive dye. The LEDs are mounted on two towers, and at the top of the tower is a tiny, low power IR laser and photodiode. With the right code running on an ATxmega16A4, the lights blink in time with the falling water droplet, making it appear the drop is hovering in midair.

Blinking LEDs very, very quickly isn’t exactly hard. The biggest problem with this build was the mechanics. The frame of the machine was machined out of polycarbonate sheets and went together very easily. Getting a consistent drip from a faucet was a bit harder. It took about fifteen tries to get the design of the faucet nozzle right, but [Mathieu] eventually settled on a small output hole (about 0.5 mm) and a sharp nozzle angle of about 70 degrees.

[Mathieu] created a video of a few hovering balls of fluorescence. You can check that out below. It’s assuredly a lot cooler in real life without frame rate issues.

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Visualizing Magnetic Fields In 3D Space

[John] is working on his PhD in experimental earthquake physics, and with that comes all the trials of becoming a PhD; tuning students into the cool stuff in the field, and demonstrating tech created after 1970 to his advisers. One of the biggest advancements in his line of work in the last 30 or 40 years is all those sensors you can find in your cell phone. The three-axis magnetometer in your phone is easily capable of measuring the Earth’s magnetic field, and this chip only costs a few dollars. To demonstrate this, [John] built a 3D compass to show off the capability of these sensors, and have a pretty light show for the undergrads.

The magnetometer [John] is using is just a simple I2C magnetometer that can be found on Adafruit or Sparkfun. It’s not really anything special, but with a little bit of code, [John] can read the magnetic field strength in the x, y, and z axes.

Having a microcontroller spit out a bunch of numbers related to the local magnetic field just doesn’t seem fun, so [John] picked up two neopixel rings – one inside the other, and set 90 degrees out of plane with each other. This turns his magnetometer and Arduino setup into a real 3D compass. With this device, the local magnetic field can be visualized in the x, y, and z axes. It looks cool, which is great for undergrads, and it’s a great demonstration of what you can do with small, cheap electronic sensors.

[John] put up a screencast of a talk he gave at the American Geophysical Union meeting last year. You can check that out below.

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Increasing The Brightness Of A Philips LivingColors Lamp

[Martin] recently purchased a Philips LivingColors lamp. It’s a commercial product that basically acts as mood lighting with the ability to change to many different colors. [Martin] was disappointed with the brightness of his off-the-shelf lamp. Rather than spend a few hundred dollars to purchase more lamps, he decided to modify the one he already had.

[Martin] started by removing the front cover of his lamp. He found that there were four bright LEDs inside. Two red, one green, and one blue. [Martin] soldered one wire to the driver of each LED. These wires then connected to four different N-channel MOSFET transistors on a piece of protoboard.

After hooking up his RIGOL oscilloscope, [Martin] was able to see that each LED was driven with a pulse width modulated signal. All he had to do was connect a simple non-addressable RGB LED strip and a power source to his new driver board. Now the lamp can control the LED strip along with the internal LEDs. This greatly extends the brightness of the lamp with minimal modifications to the commercial product. Be sure to check out the video below for a complete walk through. Continue reading “Increasing The Brightness Of A Philips LivingColors Lamp”

Adding A Backlight To A Cheap Multimeter

We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.

After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.

The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.

[via Reddit]

LED Sign Brightens Up The Beach After Dark

[Warrior_Rocker’s] family bought a fancy new sign for their beach house. The sign has the word “BEACH” spelled vertically. It originally came with blue LEDs to light up each letter. The problem was that the LEDs had a narrow beam that would blind people on the other side of the room. Also, there was no way to change the color of the LEDs, which would increase the fun factor. That’s why [Warrior] decided to upgrade the sign with multi-colored LEDs.

After removing the cardboard backing of the sign, [Warrior] removed the original LEDs by gently tapping on a stick with a hammer. He decided to use WS2811 LED pixels to replace the original LEDs. These pixel modules support multiple colors and are individually addressable. This would allow for a wide variety of colors and animations. The pixels came covered in a weatherproof resin material. [Warrior] baked the resin with a heat gun until it became brittle. He was then able to remove it entirely using some pliers and a utility knife. Finally, the pixels were held in place with some hot glue.

Rather then build a remote control from scratch, [Warrior] found a compatible RF remote under ten dollars. The LED controller was removed from its housing and soldered to the string of LEDs. It was then hot glued to a piece of cardboard and placed into the sign’s original battery compartment. Check out the video below for a demonstration. Continue reading “LED Sign Brightens Up The Beach After Dark”

Absolute Overkill IKEA Lampan Lamp Hack

Sometimes too much overkill isn’t enough. [Jesus Echavarria] hacked an IKEA Lampan light for his daughter to add color LEDs, a timer, Bluetooth control over the hue, and a local override knob. The result: a $5 lamp with at least $50 of added awesomeness. Let’s have a look at the latter.

The whole lamp system is based around a PIC microcontroller and WS2811 LEDs for the color light show. Since the lamp was already built to run a 40W lightbulb, and [Jesus] wanted to retain that functionality, he added an SSR to the build. Yeah, it’s rated for 5,000W, but it’s what he had on hand.

Top-ElementsNext comes the low-voltage power supply. [Jesus] needed 5V for the PIC, and used the guts from a cheap USB charger as a quick and dirty 5V converter — a nice hack. To power the HC-05 Bluetooth module, which requires 3.3V, he wired up a low-dropout voltage regulator to the 5V line. A level-converter IC (74LVC07) gets the logic voltage levels straight between the two.

A fuse for the high-voltage power line, screw-terminal connectors all around, and a potentiometer for manual override round out the hardware build.

On the software side, [Jesus] set up the knob to turn on and off the built-in lamp as well as control the colors of the LED ring. That’s a nice touch for when his daughter wants to change the lamp’s color, but doesn’t want to go find her cellphone. But when she does, the SPP Pro app sets the colors by sending pre-programmed serial commands over Bluetooth to the PIC in the lamp.

All in all, a nice build, well-documented, and with enough rough edges that none of you out there can say it’s not a hack. Nice job [Jesus]! We can’t wait to see what he does next… robot lamp anyone?