From 300W to 10W — A LED Lighting Solution

LED halogen light

Halogen lights are great — they produce lots of bright warm light, but they suck a lot of juice to run. [Sven] had found a nice floor lamp years ago that was in pretty rough shape — his wife redecorated it, and he fixed it up, but between the 300W power consumption and the lack of a dimmer circuit (this thing was bright!), he knew he had to upgrade.

Like we recommend for all projects, [Sven] started by setting some goals for the conversion. He wanted to keep the warm light color tone, produce over 700lm, allow for dimming via remote, and work with presence detection.

He sourced a 10W power LED which requires 12V @950mA to run, which almost stumped him as it turns out there aren’t many LED drivers of that specification even available! Luckily, he managed to find one from China that wasn’t too large and would fit in the lamp cover with the other components. He found a large heat sink for the LED, and for safety, has even wired it up with a temperature sensor to his Arduino in order to shut it down if it gets too hot. The Arduino also provides the dimming circuit and remote control capabilities.

[Sven] admits that the end result isn’t that pretty, but lucky for him, it stands about 6′ tall so no one can see the jumble of wires and components inside! This is also only the first iteration, as he plans on upgrading it further — as it turns out, 700lm isn’t quite enough.

Hard Drive Clock is Simple and Elegant

Binary hard drive clock

[Aaron] has been wanting to build his own binary desk clock for a while now. This was his first clock project, so he decided to keep it simple and have it simply display the time. No alarms, bells, or whistles.

The electronics are relatively simple. [Aaron] decided to use on of the ATMega328 chips he had lying around that already had the Arduino boot loader burned into them. He first built his own Arduino board on a breadboard and then re-built it on a piece of protoboard as a more permanent solution. The Arduino gets the time from a real-time clock (RTC) module and then displays it using an array of blue and green LED’s. The whole thing is powered using a spare 9V wall wort power supply.

[Aaron] chose to use the DS1307 RTC module to keep time. This will ensure that the time is kept accurately over along period of time. The RTC module has its own built-in battery, which means that if [Aaron's] clock should ever lose power the clock will still remember the time. The RTC battery can theoretically last for up to ten years.

[Aaron] got creative for his clock enclosure, upcycling an old hard drive. All of the hard drive guts were removed and replaced with his own electronics. The front cover had 13 holes drilled out for the LED’s. There are six green LED’s to display the hour, and seven blue LED’s for the minute. The LED’s were wired up as common cathode. Since the hard drive cover is conductive, [Aaron] covered both sides of his circuit board with electrical tape and hot glue to prevent any short circuits. The end result is an elegant binary clock that any geek would be proud of.

The First Arduino Radar Shield

The first Radar Arduino ShieldThe very first fully operational radar Arduino shield was recently demonstrated at Bay area Maker Faire. It was built by [Daniel] and [David], both undergrads at UC Davis.

Many have talked about doing this, some have even prototyped pieces of it, but these undergrad college students pulled it off. This is the result from Prof. ‘Leo’ Liu’s full-semester senior design course based on the MIT Coffee Can radar short course, which has been going on for 2 years now. Next year this course will have 30 students, showing the world the interest and market-for project based learning.

Check out the high res ranging demo, where a wider band chirp was used to amazing results. Video below.
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Do You Have Any Idea How Fast Your Blender Was Going?

blenderSpeed Some people really love their smoothies. We mean really, really, love smoothies and everything about making them, especially the blenders. [Adam] is a big fan of blenders, and wanted to verify that his Vitamix blenders ran as fast as the manufacturer claimed. So he built not one, but two speed measuring setups. Scientific blender measurement method requires one to cross check their results to be sure, right?

Measuring the speed of a blender is all about the RPM. Appropriately, [Adam's] first measurement tool was an LED based stroboscope. Stroboscopes have been around for hundreds of years, and are a great way to measure how fast an object is rotating. Just adjust the speed of a flashing light until the rotating object appears frozen. The number of blinks per second is then equal to the Rotations Per Second (RPS) of the object being measured.Multiply by 60 seconds, and you’ve got RPM. [Adam] used an Arduino as the brains behind his stroboscope. He wired a dial up on his breadboard, and used it to adjust the flash rate of an LED. Since this was a quick hack, [Adam] skipped the display and just used the Arduino’s USB output to display speed measurements on his laptop.

There are possibilities for error with stroboscopes. [Adam] discovered that if the stroboscope was flashing at a multiple of the blade’s rotation speed, the blades would appear frozen, and he’d get an erroneous RPM value. Thankfully, [Adam's] Vitamix had asymmetric blades, which made the test a bit easier. He calculated his blades to be spinning at 380 RPS, or 23,000 RPM. Not satisfied with his results, [Adam] brought out Audacity, and ran a spectral analysis of the blender in operation. He found a peak at 378Hz, which was pretty darn close to his previous measurement. Since the blender has a 4 inch blade this all works out to a blade tip speed right around the claimed value of 270 MPH. We’re glad [Adam] found an answer to his blender questions, but our personal favorite blender hack still has to be the V8 blender created by the Top Gear crew.   [via HackerNews]

‘Ol Painless Paintball Mini-gun Packs a Mean Punch

Ol Painless Mini Gun

Remember Predator? Of course you do. This is [Corsae's] personal paintball gun rendition of one of the guns from it, ‘Ol Painless.

It’s a beautiful piece of work with countless man-hours going into its creation. At the core is an off-the-shelf EGO 08 paintball gun with a 20″ barrel. The barrel spacers are made out of MDF, cut by hand using a jigsaw with a barrel guide. The guide itself was made on a CNC router — too bad he couldn’t use it for everything! Each barrel is a thick-walled aluminum tube, carefully fit into the guides, and spray painted matte black for a clean finish. Sadly, they are only for aesthetics, as the paint balls shoot out through the central barrel only.

Not to worry though – while the paint balls may not come out of the barrels, the whole thing spins menacingly, which brings us to our favorite part of the project — the electronics. With help from his friend he designed a custom Arduino shield to control the motor, status LEDs and solenoid trigger. It’s fairly basic, but cool nonetheless. It features some wire connectors, diodes, an LED and the motor driver. Since the PCB fabrication cost included screen printing, he even threw on a mini-gun logo.

He’s done great job documenting the entire project in a photo gallery, with lots of notes along the way — stick around after the break to see a video of it shredding up the field.

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MIDI Melodies Make Moody Milieu

MIDI piano lights

In this beautiful, well-documented, cat-assisted hack, [capricorn1] adds visual dimension to his impressive piano skills by using his keyboard’s MIDI output to drive Edison bulbs.

He hung them from a rod of electrical conduit pipe and threaded the wires through it to a DB25 connector. The lights are controlled by an Arduino Mega plus a custom shield with an optocoupler to handle zero cross detection. He happened to already have a board with 12 SSRs on it from another project. All of the electronics are in a re-purposed switch box—the switches control four different modes: classic, velocity, scrolling, and automatic. You’ll see the scrolling mode in the video after the jump.

[capricorn1] used a small sampling of the Arduino MIDI Library, namely the note on/off functions and the control change function to handle his sustain pedal. He’s listed the full code for the project, which includes usage of the ipMIDI module for automation over WiFi.

If you don’t have a MIDI keyboard or any Edison bulbs, you could make a MIDI floor piano. You’re required to play both “Chopsticks” and “Heart and Soul” on it, though. Those are like the Hello, World for floor pianos.

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640×480 VGA On An Arduino

VGAThere are dozens, if not hundreds of examples around the Intertubes of an Arduino generating a VGA video output. The Arduino isn’t the fastest chip by far, and so far, all of these VGA generation techniques have peaked out at lower resolutions if you want to control individual pixels.[PK] has an interesting technique to generate 640×480 VGA at 60 frames per second without overclocking. It’s hacky, it’s ugly, but surprisingly, it actually works.

The VGA standard of 640×480 @ 60 fps requires pixels to be clocked out at 25.175 MHz, and the ATMega chips found in Arduinos top out at 20 MHz. [PK] wanted to generate VGA signals without overclocking, He did this by doubling the clock frequency with digital logic. The ATMega generates a clock, an inverter delays that clock so it is 90 degrees out of phase, and the two clocks are XORed, doubling clock output of the micro. It produces a very ugly square wave at 32 MHz – an error of 27% compared to the VGA spec. Somehow it still works.

With a hilariously out of spec clock, the rest of the project was pulled together from [Nick Gammon]‘s VGA library, a 16×16 font set, and a project from [lft]. Video below.

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