PICAXE Using LEDs To Communicate

March 15, 2011 by Mike Szczys 16 Comments

[Relwin] has being working on using LEDs as bi-directional devices. The setup above allows him to use each LED as an input, looking for a bright light source and then syncing up with the activity it receives. It is the most basic of communications using the components. The hardware at the heart of the system is a PICAXE development board on the left. The blinking light to the right causes the LED on the left of the picture to blink, but moving the blinking source over to that side will reverse the effect. The chip is programmed to play a tune on a piezo buzzer whenever a connection is lost. What is interesting to us is that these green LEDs will not detect a red LED flashing because the voltage threshold is different on the detector side of things.

He’s got some code available, but we’re really looking for the ideas of what to do with this concept. Maybe something along the lines of LED matrix video puzzles, or a variation on this laser-pointer LED game. Watch the demo video after the break and then let us know what you would use it for by leaving a comment.

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ASync-Firefly

March 11, 2011 by Noah Dunker 8 Comments

[dev_dsp] wanted to try his hand at creating a purely analog implementation of multiple synchronizing fireflies powered by a single battery and built from off-the shelf, through-hole components on inexpensive protoboard. In theory, even your local Radio Shack should still carry all of this stuff. He was obviously inspired by [alex]’s fireflies that we’ve covered in the past, but he wanted to see how far it could be taken without the use of a microprocessor.

In the end, [dev_dsp] relied on one crucial piece of digital ware, the ever-popular 555 timer IC, but he’s using analog discrete components to do the grunt work of adjusting the phase of each firefly by feeding a little extra current to the trigger capacitor whenever the flash of a nearby firefly is detected. After the jump, you’ll find schematics and a video demo of three ASync-Firefly modules in various stages of assembly playing with one another while [dev_dsp] discusses their operation.

Lol Shield Theatre Brings Online Video To The Pixelated Screen

March 11, 2011 by Mike Nathan 4 Comments

lol_shield_theatre

[FallDeaf] bought a Lol Shield, and after making all sorts of blinky displays, he thought to himself, “What in the world can I use this thing for?”

In a really slick fusion of hardware, software, and the power of the Internet, he has created what he calls, “Lol Shield Theatre”.

The idea goes something like this:

You visit his site, and create your own “movie” by drawing on his virtual Lol Shield. Add as many frames as you would like, set the frame rate, then submit your creation. From there, you can download an Arduino sketch that contains your entire animation so you can play it on your own Lol Shield. You can also visit his Lol Shield gallery, where you have the ability to watch, download, and vote on movie submissions from other visitors.

He has also provided the source code to drive your Lol Shield, as well as created an API through which you can stream the various animation feeds from his Lol Shield gallery directly to your Arduino via a USB cable.

Be sure to check out the video demo we have embedded below, and show off your pixel cinematography skills over in the theatre.

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Bitbang IR Remote

March 11, 2011 by Kevin Dady 4 Comments

[Albert] has made a few PC IR transmitters and receivers using the traditional connection of RS232 serial, and that is fine, but as we are all aware, not every computer has serial ports standard. Searching though normal USB <> RS232 dongles didn’t meet his requirements. Deciding on making it himself, he whipped up this FTDI bit-bang IR receiver / transmitter.

While FTDI makes a range of chips most (if not all) support a bit-bang mode where you can manually control the IC’s pins. The FTDI chip handles the timing, and when paired up with libFTDI makes it pretty painless to control. The software is a work in progress, but [Albert] already has a driver that connects to LIRC, which lets you control a wide array of remote devices and a test program for carrier generation.

Schematics, source, and a few pages of good information are available on his site.

Water Droplet Sculpture Using LEDs And Arduino

March 11, 2011 by Mike Szczys 19 Comments

This water sculpture can stop drops of water in mid-air. This is accomplished by flashing LEDs to illuminate the droplets at just the right time. But it’s not limited to blinky lights alone. The top of the frame has eight nozzles, each fed by its own pump. An Arduino controls the pumps and the lights making it possible to create different motion effects by adjusting how events line up. For instance, the image above shows just two of the water nozzles on, but in the video after the break it appears one is dripping downward while the other is dripping upward.

Alas, there’s few build details for this but the source code is available for downloading. If we were going to build one of these ourselves we’d probably try to regulate the drips using some solenoids built from scratch. How would you do it? Leave your ideas in the comments.

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DIY Flower Bouquet Guaranteed To Get You Dumped On Valentine’s Day

March 10, 2011 by Mike Nathan 36 Comments

led_flower_bunch

[Erik] is a broke engineer.

When this past Valentine’s day rolled around he didn’t have any cash to buy a gift for his girlfriend, so he had to get creative. Every girl likes flowers, but unless he was going to give his lady some day old daises from the grocery dumpster, he would have to make them himself.

He started by bundling together and bending some T-shirt hangers into stems. He then wrapped them in the green & green/white wire pairs from some Cat-5 cable to give them some color. An old keyboard was sacrificed to create the flower petals and leaves, which were presumably colored with markers before being glued to the end of the hangers. He added a reed switch to the flower pot, which illuminates the LEDs he installed under the petals when a magnet-bearing cardboard placard reading “Love Erik” was placed near it.

How did his girlfriend like them? Well, let’s just say she’s no longer in the picture. He didn’t tell us if the bouquet was the reason, only that she’s gone. (though we happen to think it’s pretty cool).

Keep reading to see a quick video demonstration of the light-up bouquet.

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Shedding Some Light On Your Kitchen Chores

March 8, 2011 by Mike Nathan 13 Comments

led_light_bar

[Garret] over at Macetech wanted to supplement the lighting over his kitchen sink, which is always too dark at night. He says his house is a “geek house”, so a standard light socket just wouldn’t do – he would have to construct a LED bar for over the sink instead.

Since nobody wants to use a light switch with wet or messy hands, he did what anyone would do and rigged up a motion detection circuit to automatically turn the lights on and off for him. 16 bright white 10mm LEDs were mounted in some foam core board, along with a PIR motion sensor. He used an ATiny84 to handle the PWM fade-in and fade-out of the lights, as well as to keep track of the activity (or lack thereof) at the sink.

He does admit that the ATiny84 is way overpowered for this project, but he lacked anything smaller, and says that 555 timers wouldn’t give him the smooth light fading that he desired. Regardless, it works as advertised, and now nobody has to peel potatoes in the dark any more.

Continue reading to check out a quick video demo of the motion-sensing light system.

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