Need A Small, Cheap Ammeter? Blinkenlights To The Rescue!

You know how it is. You’ve got that new project running, and while it doesn’t consume much power, it also doesn’t give much indication of whether it’s functioning or just sitting there with a dead battery. What you need is an ammeter to check power consumption, even from across the room. And it just so happens that [Manuka] has Just The Circuit You Need, complete with a demonstration in the video after the break!

Oh sure, you could grab a cheap ammeter at your favorite tool import store or site, but those are bulky and take batteries. You could put in an LED that gets dimmer as voltage drops. But wait- is that the sun shining on it? or is it on? Or has something gone awry and it’s consuming too much power?

What [Manuka] gives us is a circuit that is designed to be built into your project or project’s power supply. Using only an ultra-bright white LED, red blinking LED, PNP transistor, and a diode, the circuit gives a strong visual indication of current consumption by blinking brighter and more frequently as current increases. With a bit of calibration, accurate measurements can be obtained. All of this is made possible by using the Flashing LED as a driver for the ultra-bright LED, which is a pretty slick hack!

Flashing LEDs have a great number of uses, like protecting your family from lions. Yes, really. Got a cool tip for flashing LEDs, blinkenlights, 555’s, or any odd thing that strikes your hackers fancy? Let the tip line know!

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BEAM Dragonfly Causes A Flap

Normal people throw away stuff when it breaks. But not people like us. Or, apparently, [NanoRobotGeek]. A cheap robotic dragonfly died, and he cannibalized it for robot parts. But he kept the gearbox hoping to build a new dragonfly and, using some brass rod, he did just that.

The dragonfly’s circuitry uses a solar panel for power and a couple of flashing LEDs. This is a BEAM robot, so not a microcontroller in sight. You can see a brief video of how the dragonfly moves.

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1768 LEDs, Because 96 Just Wasn’t Enough

Some people would look at a massive 6’x4′ LED matrix hanging on the wall playing animations and be happy with the outcome. But [Ben] just isn’t one of those people. The original FLED (Fantastic LED thingy) was eight rows of twelve addressable LEDs for a total of 96 pixels. This spring he upped his game and retrofitted the display with 1768 LEDs.

It wasn’t simply an issue of restlessness, the original build suffered from LEDs dying. We actually featured it for that reason as a Fail of the Week.  This is not strictly a hobby project, it’s hanging on the wall in the Supplyframe offices, so pulling it down frequently to fix broken parts is not ideal.

fled-reborn-LED-layoutTo make FLED more reliable [Ben] sourced strips of the new APA102 LEDs which we looked at back in December. They use an SPI bus instead of the bizarre timing scheme of the WS2812. At first glance you’d think this would mean easier assembly compared to soldering both sides of each of the original 96-pixels. These do come in strips, but laying out 52×34 still means soldering to the ends of each row.

A lot of love went into making sure those rows were laid out perfectly. A sheet of white foamed PVC serves as the substrate. There is grounding braid on either end of the rows, one is the voltage bus, the other is ground. It fits the original enclosure which is acrylic and does a great job of diffusing the light. I’ve seen it in person and it looks pretty much perfect!

It’s not just the physical layout of this many pixels that is a challenge. Pushing the data to all of them is much harder than it was with 96. [Ben] transitioned away from RaspberryPi. He considered using a Teensy 3.1 and ESP8266 but the WiFi of these cheap modules is far too slow to push frame information from a remote box. In the end it’s a BeagleBone Black that drives the reborn display. This is a great choice since there’s plenty of power under the hood and a traditional (and much faster) WiFi dongle can be used.

Don’t miss the animation demos found after the break.

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Fail Of The Week: WS2811 Pixel Failure On FLED

This Fail of the Week project comes from one of Hackaday’s own. [Ben] took on the FLED data visualization project as a way to make the SupplyFrame decor a lot more fun. He had quite a bit of help soldering the 96 WS2811 pixels into their custom made 6’x4′ enclosure and the results are really awesome. In addition to showing server load and playing games, FLED has become something of a job interview. Sit the prospective employee down at a terminal and give them an hour to code the most interesting visualization they are capable of.

But two weeks ago [Ben] staggered into the office and found the display was dead. Did he try turning it off and back on again? Yes, but to no avail. The power supply wasn’t the issue and there was no option but to pull the display off the wall and crack it open for a look at all those pixels. Since every one of them had 4 solder joints on either side he figured the problem was with a broken connection. But not so. He resorted to a binary search for the offending pixel by  cutting the strand in half, and testing each portion. He tracked it down to the pixel whose underside was blackened as you can see above.

[Ben] thinks one of the capacitors inside the sealed enclosure blew, but isn’t certain. Feel free to tell us what you think failed in this component. But the thing we’d really like to know is if there is a more clever way to sniff out the offensive pixel without cutting the connections? Four hours on the floor with this thing (and no knee-pads) and [Ben] has sworn off sourcing pixels from random Chinese suppliers. He might go with pre-assembled strings next time. We chuckle; this is the high-tech equivalent of trying to get old strands of Christmas lights to work.

If you haven’t seen FLED in action, check it out after the break. It amazing how LED intensity and quality diffuser material can make a perfect grid of LEDs seem to dance in waves and color curves.

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