[Jeri Ellsworth] had a bright idea – a brain-activated light bulb that floats above your head. While out and about, she saw some guy with a video game icon attached to metal rod sticking out of his backpack. The rod made the icon appear to be floating above his head (think The Sims), which was the inspiration for this LED powered light bulb. The bulb is connected to a metal rod, as well as a metal hoop which is springy enough to keep a pair of electrodes snugly attached to your head.
Those electrodes, along with a third probe used for noise reference, are hooked up to a AD620 instrumentation amplifier. With the help of op amps, it modulates the red or green LEDs that are attached to the back side of the light bulb. The end result is an amusing way to show brain activity while being grilled on a Q/A panel, or while just wandering around taking in all the amazing sights presented at Maker Faire.
Join us after the break for a video demonstration.
Continue reading “A Bright Idea”
In her new element-14 video [Jeri Ellsworth] explains some concepts about “free to you” energy and features the LTC3109EUF, an Auto-polarity, Ultra low Voltage Step-Up Converter and Power Manager, along with the LTC3588EMSE a Piezoelectric Energy Harvesting Power Supply.
Using the LTC3109EUF she is able to power a modified Nintendo Entertainment System, and LCD using a small generator and an exercise bike. The LTC3588EMSE is wired up to piezo’s in different applications including being squashed, vibrated, and temperature difference to power low current devices.
All this and a totally 80’s theme, so poof up your hair, get your spiked dog collar, and find those neon green shades because this is a fun and informative video available on element-14.
Remember how fun it was studying chemistry and physics in high school? Well we guess your recollection depends on the person who taught the class. Why not have another go at it by learning the A-to-Z of electronics from one of our favorite teachers, [Jeri Ellsworth].
You know, the person who whips up chemistry experiments and makes her own semiconductors? The first link in this post will send you to her video playlist. So far she’s posted A is for Ampere and B is for Battery, both of which you’ll find embedded after the break. Her combination of no-nonsense technical explanation, and all-nonsense paper-doll history reenactment make for a fun viewing whether you retain any of the information or not.
Continue reading “Let paper dolls teach you science”
[Jeri Ellsworth] has put together a couple of videos that cover how she made her own organic light emitting diodes, or OLEDs. In the first video, after the break, it discusses the difference between regular, rigid semiconductor LEDs and organic LEDs. The video then goes on to show how to make an OLED as successive layers of materials. Indium tin oxide (ITO) on glass forms a transparent anode. That is then coated with PEDOT:PSS, a conductive polymer mix that is used as a hole transport layer. Then a red diamond ruthenium complex is added to create the emissive layer. The cathode layer is a low work function metal, initially, gallium indium eutectic alloy then later other metals were shown to work. The second video, shows how to juice a glowstick and make OLEDs with the liquid. The dye in blue glowsticks, 9,10-Diphenylanthracene, is an organic semiconductor and will emit light as an electric current is passed through it. The glow stick method seems to have some problems as the ITO coated glass plate is degraded by the glowstick chemicals. It would be interesting to see if using the porous aluminum or similar technique from [Jeri]’s flexible electroluminescent displays could be used as an electrode.
Continue reading “DIY OLEDs”
A failed chemistry experiment led [Jeri Ellsworth] to discover a flexible substrate for electroluminescent displays. We’re familiar with EL displays on the back of a glass panel like you would find in an audio receiver, but after making a mesh from aluminum foil [Jeri] looked at using the porous metal to host phosphors. She starts by cleaning foil and using a vinyl sticker to resist etching portions of the aluminum. It then goes into a bath of boric acid, electrified with the foil as the anode. As the foil etches she tests the progress by shining a laser through the foil. After this the phosphors are applied to the back surface of the foil, covered in a dielectric, and topped off with a conductive ink that will carry the AC necessary to excite the phosphors. This is layering materials in reverse compared to her EL PCB experiments. See [Jeri] explain this herself in the clip after the break.
You can see above that this produces a pretty well-defined display area. It reminds us of that color changing paint display. We think it would be worth a try to build a few 7-segment displays using this method.
Continue reading “Jeri makes flexible EL displays”
Tired of breathing all the noxious fumes your laser cutter puts out? Yeah… we don’t have a laser cutter either. But [Jeri Ellsworth] does and she needed a way to evacuate off-gases generated during cutting so that they don’t damage the laser cutter, or her lungs. What she came up with is a containment box that attaches to a pump system.
The problem is that you want to keep the gases away from the laser cutter hardware but you still need to be able to shoot the laser at your work material. Her clever solution is to use a silicone wafer like the ones with which she makes integrated circuits. They allow the infrared laser to pass through without being chopped in half. What you see in the image above is a red box with the round wafer in the center. Near the bottom of the image is a clear window so you can see what’s going on with your work piece. But to get the full idea you need to watch the video embedded after the break.
We can’t help but think she’s building this in preparation for some more chemistry hacking.
Continue reading “Gas containment for laser cutters”
[Jeri’s] back with a series of videos that outlines the step-by-step electroluminescent wire manufacturing, making EL panels from PCBs, and assembling power supplies for EL hardware. These concepts are actually quite approachable, something we don’t expect from someone who makes their own integrated circuits at home.
The concept here is that an alternating current traveling through phosphors will excite them and produce light. You need two conductors separated by a dielectric to get the job done. For wire, [Jeri] uses one strand of enameled magnet wire and one strand of bare wire. The enamel insulates them, protecting against a short circuit.
But that’s not all, she also tests using a circuit board as an EL panel. By repurposing the ground plane as one of the conductors, and using the solder mask as the dielectric she is able to paint on a phosphor product resulting in the glowing panel.
Finally, you’ve got to get juice to the circuit and that’s where her power supply video comes into the picture. We’ve embedded all three after the break. It’s possible that this is cooler than blinking LEDs and it’s fairly inexpensive to get started. The circuitry is forgiving, as long as you don’t zap yourself with that alternating current.
Continue reading “EL Wire: make it, connect it, power it”