Scratch-built Smart Flashlight

December 2, 2013 by Mike Szczys 13 Comments

scratch-built-smart-flashlight

This flashlight has a face; one of the many tricks which [Hobbyman] included during the development process. The smart flashlight build turned out to be a great way to practice so many different aspects of product development.

It was envisioned as a light for use when walking or biking that could do more than just light your way or flash on and off. Of course we know it’s really just a reason to spend way too much time in his lair. He started with the electronics, driven by a PIC 16F88. The 5×5 LED matrix gives him just enough to work with for patterns and rudimentary text. The prototype is wrapped up into a pretty tight package which leaves enough room in the 3D printed case for 4 AAA batteries. As the project progressed more and more features were added in. The most current offering includes a temperature sensor as well as the ability to react to ambient sound. See for yourself after the break.

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Arduino Christmas Lights

December 1, 2013 by James Hobson 12 Comments

Here’s a cool hack to get you in the December holiday mood! Arduino controlled Christmas lights!

It all started because [Anx2k] had some leftover LED’s from one of his other projects, so he decided to make use of them as permanently mounted Christmas lights. He’s installed them underneath his tiled roof, and run all the wires into his attic where he has an electrical box serving as the main control hub. He uses an Arduino Uno to control them, and a 460W computer power supply to provide the juice. The LED modules themselves are Adafruit RGB pixel strings. There’s actually three of the LED modules per tile — two shining up to illuminate the tile, and one shining out.

He’s set up a ton of different patterns to run, and they are pretty awesome! Check out the video after the break.

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RFID RGB Lamp Goes The Distance

November 29, 2013 by Mike Szczys 5 Comments

[Philippe Chrétien’s] project makes it to our front page just based on its completeness. When you hear about a multicolored lamp which changes based on an RFID tag you might not get too excited. When you look at the refined electronics and the quality of the wooden enclosure it’s another story entirely.

As we’ve said many times before, coming up with the idea for a project is the hardest part… especially when you just want to start hacking. With his kids in mind [Philippe] figured this would be something fun for them to play around with, opening the door to discussing the electronics concepts behind it.

He prototyped on a breadboard using three N-type MOSFETs to drive the colors of an RGB LED strip. The proven circuit was laid out and etched at home to arrive at the clean-looking Arduino shield shown off above. The entire thing gets a custom enclosure cut using layered plywood, a paper template, and a bandsaw.

Need a use for this once the novelty has worn off? Why not mod it to use as a motion activated night light? Alas the actual project link for that one is dead, but you get the idea.

Maglite 18650 Battery Conversion

November 28, 2013 by James Hobson 30 Comments

maglite 18650

Maglite’s used(?) to be the king of flashlights, but replacing those pesky D-cell batteries is kind of ridiculous in this day and age. So [Travis] decided to upgrade it to make use of the ever-so-common, 18650 lithium-ion battery.

Not looking to purchase any components [Travis] performed this hack using simple recycled household parts. You could solder tabs on the 18650’s so they better mimic a typical alkaline battery cell, but [Travis] notes that because most solder tarnishes the electrical conductivity isn’t always the greatest. So instead, he used aluminum foil. It doesn’t look professional, but it does the job and keeps all the components unmodified so the lithium cells can be used elsewhere if needed. To center the batteries inside the Maglite he used a few strips of cardboard from a case of beer — again, this is just making use of what was available. That being said however, if you wanted to do a professional job on it, nothing is stopping you! A 3D printed 18650 to D-cell adapter would look quite nice… Finally, in order to make the battery spring contact the smaller surface area of the lithium cells, all you have to do is flip it around backwards and slightly bend the inner spring out. That’s about it.

It’s a pretty simple hack we admit, but definitely super handy. In a past project [Travis] also replaced the halogen bulb with a high power LED, making this flashlight even more powerful — and because the LED driver accepts a broader range of voltages it lasts longer too. If you need more inspiration for retrofitting flashlights with LEDs check out this switch-mode driver board hack.

Unfortunately this hack does reduce the Maglite’s thief-head-bashing-ability with such light batteries.

Using DMA To Drive WS2812 LED Pixels

November 22, 2013 by Mike Szczys 17 Comments

It’s pretty well known by now that the LED pixel hardware which is starting to be commonplace, both WS2811 and WS2812, needs pretty strict timing in order to address them. There are libraries out there which mean almost no work on your part, but that’s no fun. [Elia] started looking into what it takes to drive the hardware, trying out a few 8-bit micros before moving to 32-bit with the help of an STM32VL Discovery Board. The move to a beefier processor brings a lot of speed, but why bit bang everything? He came up with a way to use the PWM and DMA features of the chip to drive the LEDs.

DMA is the Direct Memory Access unit that allows you to change the values being sent to the pixel without interrupting the processor. This is done by pre-loading the data at a memory location. This buffer is automatically read by the DMA unit — its values are used to set the PWM timer compare trigger in order to send out logic values show in the diagram above.

If you do want to delve further into this topic here’s a collection of techniques for driving the WS2811.

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Simple 10 Watt LED Driver Is Hot Stuff

November 20, 2013 by Adam Fabio 23 Comments

[Peter] needed to drive a high power LED for his microscope. Rather than pick up a commercial LED driver, he built a simple constant current LED driver and fan control. We’ve featured [Peter’s] pumpkin candle LED work here on Hackaday in the past. Today he’s moving on to higher power LEDs. A 10 watt LED would be a good replacement light source for an old halogen/fiber optic ring light setup. [Peter] started with his old standby – an 8 pin Microchip PIC. In this case, a PIC12F1501. A PIC alone won’t handle a 10 watt LED, so he utilized a CAT4101 constant current LED driver from ON Semi. The PIC performs three tasks in this circuit. It handles user input from two buttons, generates a PWM signal to the LED driver, and generates a PWM signal for a cooling fan.

Control is simple: Press both buttons and the LED comes on full bright. Press the “up” button, and the LED can be stepped up from 10% to 100% in 10 steps. The “down” button drops the LED power back down. [Peter] even had a spare pin. He’s currently using it as an LED on/off confirmation, though we’d probably use it with a 1wire temperature sensor as a backup to thermal protection built into the CAT4101. It may be overkill, but we’d also move the buttons away from that 7805 linear regulator. Being that this circuit will be used with a microscope, it may eventually be operated by touch alone. It would be a bit surprising to try to press a button and end up with a burnt fingertip!

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A POV Spinner Display With Arduino

November 18, 2013 by Adam Fabio 3 Comments

pov-display

[Martin2250] has been working on a spinning disc style POV display. He’s posted his progress up on reddit. This hack is a great example of using what you have at your disposal. [Martin2250] is using an IR LED and photodiode to determine the rotational speed of the disc. He tried using the Arduino micros() function to delay between the photodiode pulse and turning on his LEDs. As [Martin2250] found out, micros() isn’t quite accurate enough for this purpose. He’s since switched over to using the AVR’s native timers, and is getting much better results.

The disc in this build is actually a CD. [Martin2250] sanded away the label, then masked out his digits. He “painted” the CD with a black marker. Peeling off the tape revealed his stylized digits. Cardboard, hot glue, and visible LEDs were used to create four light boxes for the digits. The disc can display any four digits at once – perfect for a POV clock. We love the use of on-hand materials in this hack – bits of hard and balsa wood, liberal use of hot glue, and of course cardboard. The only thing missing in our eyes is some duct tape!