Hack a Solar Garden Light Into a Flashlight


While browsing through his local dollar store, [Taylor] came across a suspicious looking rock that, upon closer inspection, turned out to be a solar garden light. He scooped it up, took it home and cracked it open, modding it to function as a handheld solar flashlight.

Inside was a pathetically small 40mAh rechargeable battery, which he upgraded to a more standard rechargeable AA. The garden rock came pre-built with its own boost converter to kick up the voltage for the LED, but it was fairly dim. We’re guessing [Taylor] didn’t bother reverse engineering the converter and instead simply did some trial and error, but he managed to increase the LED’s brightness by slapping on a different value inductor.

As fun as it may be to have a rock for a flashlight, [Taylor] decided to cobble together a custom case out of a spare USB charger, making a battery holder and adding a pushbutton. The result is a handy solar flashlight that takes around five hours to charge. Check out some other custom lights: a lithium-powered PVC flashlight or one with a snazzier aluminum body and interchangeable heads.

Giving a crank flashlight a super capacitor overhaul


[Caleb] was given a tiny LED flashlight which has a crank used to charge it. Unfortunately it wasn’t holding a charge, and constant cranking didn’t work very well either. He cracked it open to find a single lithium button cell. Instead of using a drop-in replacement he soldered in his own super capacitor.

The stock device is remarkably simple. It uses a standard DC motor as the generator. It’s connected to the crank using a set of gears, with the two red wires seen above connecting it to the control board. Four diodes make up a bridge rectified and apparently feed directly into the battery. No wonder that cell went kaput!

But this orientation isn’t bad for using capacitors. They can be charged directly and the switch which attaches the LEDs to voltage doesn’t interfere with their operation. The last problem was making room for them in the case. [Caleb] considered a few different approaches, but ended up just heating the plastic enclosure until it could be deformed to make room for the additional parts.

DIY Lighting Solutions


With daylight savings time starting up, you might not have quite as much need for lighting, but this pair of hacks should keep everything well lit whether outside or indoors.  Check out the videos of both in action after the break.

The first lighting solution comes to us from [Ben]’s Youtube channel. It’s a simple solution, press-fitting a clamp light into a 1 inch PVC Tee to attach the light to a pipe. The base is made with PVC shaped into three feet for a (hopefully) sturdy rest.  Several lights can be used as needed, and would probably work well for making his next video.

The second light also comes to us from Youtube, and is about converting a stock LED light into one that is much brighter. Skip to around 7:00 to see the outdoor comparison.  You may or may not want to do this exact hack, but you never know when you might want to swap out your blinkenlights for something that will scare the neighbors!
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Recycle lithium cells by building custom flashlights

This isn’t a brightest flashlight in the world type of hack (but it does manage to push about 1000 lumens). [Stephen Webb] is finding a use for leftover parts by building his own simple LED flashlights. As you can see, he uses PVC parts available at any hardware or home store. These are a good choice; they’re cheap, light weight, resilient, designed to be water tight, they easily thread together and have connectors that reduce the diameter of the fittings.

The electronics use standard size cylindrical Lithium cells. These are found in many types of Laptop and Power Tool batteries. Often when one of those battery packs bites the dust it’s an issue of one or more bad cells. [Stephen] desolders the cells, and reuses the good ones in this project.

We didn’t see any mention of a recharging technique. Does anyone have any advice on how to top these cells off if they’re not in their original power pack form?

Monitor your heartbeat with a webcam and a flashlight

After seeing some heart rate monitor apps for Android which use the camera and flashlight features of the phones, [Tyson] took on the challenge of coding this for himself. But he’s not using a smart phone, instead he grabbed a headlamp and webcam for his heat rate monitor.

To start out he recorded a test video with his smart phone to see what it looks like to cover both the flash LED and camera module with his thumb. The picture is mainly pink, but there’s quite obviously a color gradient that pulses with each gush of blood through his skin. The next task was to write some filtering software that could make use of this type of image coming from a webcam. He used C# to write a GUI which shows the live feed, as well as a scrolling graph of the processed data. He took several tries at it, we’ve embedded one of the earlier efforts after the break.

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Laser so easy to build anyone can burn their eyes out

The boys over at North Street Labs built a handheld burning laser and made it look super simple. Well it’s not. We don’t think it’s hard either, but the only reason it looks so easy is because they really know what they’re doing.

The first step was to source the best parts for the application. They’re using a handheld flashlight body which is small but still leaves plenty of room for the components. Next they ordered a quality lens made for the wavelength of the diode, as well as a prefab driver board.

Now the real build starts. They hit the metal lathe and machined a housing for the diode out of some aluminum stock. To marry the parts together they applied some thermal paste, and used a wrench socket to protect the diode from the pressure the vice jaws exert. It slid into place and the whole thing fits perfectly in the flashlight housing. The project wouldn’t be complete without video proof of it burning stuff. You’ll find that after the break.

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A flashlight for any occasion

Whether you’re trying to light your path, build your own night vision, or do some tanning at home, this flashlight has you covered. [David Prutchi] designed the high power flashlight with three swappable heads.

He built the base unit out of aluminum pipe. It’s got plenty of room for the four 9V batteries that act as the power source. The driver circuit is just a bit smaller than one of those batteries, and to bring the whole thing together [David] and his helper added a potentiometer, toggle switch, and quick connector which makes head swaps a breeze. The heads themselves are all LED based, with one for visible light, another for infrared, and the final module outputs ultraviolet. We joke about tanning with it, but at 10 Watts you should be more worried about accidental damage to your vision.

The finished product is shown checking the security ink on some Canadian Currency. This would also make a nice secondary light source for your night vision monocle.