This instructable is about the construction of the ultimate scorpion hunting flashlight called the "Scorpion Stinger". It functions extremely well and knocks the socks off of the competition.  Check out the videos in the "Field Testing" section of Step #13!

Scorpion Stinger features:
  • Uses a re-purposed halogen flashlight that was acquired new for $10 which provides a plastic case with plenty of room inside for custom PCB's, a high discharge 3.7V 2200mA lithium battery, recharging circuitry, a trigger switch, a wall charger, and a car charger.  What a deal for $10.
  • The custom LED driver board sports 2 identical circuits that will boost a wide range of battery voltages (3V to 5 V)  to a variable voltage output of up to 18 volts at a constant current of 200mA each circuit.  The output current can be adjusted by a changing a single resistor.  This switched mode boost power supply also has a feature of over voltage protection should the LED's become disconnected during operation. This circuit is easily adaptable to support PWM dimming.

This instructable was submitted by the author, who is a member of  the Xerocraft Hackerspace in Tucson, Arizona , for additional consideration for the "Instructables Sponsorship Program".

In the desert southwest of Arizona,   scorpions are plentiful.  Because they can squeeze into tiny of cracks, sometimes you find them in your house, too.  For the good of all concerned, it is usually best to keep your property free of scorpions. Scorpion bites can be deadly to the very old, the very young, or people allergic to the scorpion venom.  In recent news, a lady was bitten by a nasty scorpion and left her with a $83,000 hospital bill, with nearly $40,000 of that bill for the anti-venom alone.

Recently, our home owners association received complaints of a large amount of scorpions in backyards along a particular street.   An exterminator found the source of the scorpions to be a large drainage ditch that was lined with large stones.  These large stones made for a perfect scorpion habitat.  Scorpions are notoriously difficult to kill using chemicals.  The exterminator said that because the scorpion population was in a drainage ditch that was considered a waterway, and he could not treat this area with chemicals or risk the wrath of the EPA for dumping chemicals into a waterway.  So, we were left to find another more environmentally sensitive solution.

Fortunately, scorpions are florescent and glow in the dark when illuminated with certain wavelengths of ultra violet light. It is really creepy to see, especially when they start to move.  Since chemicals are not an option, it was proposed that periodic nighttime patrols of the ditches with UV flashlights would allow for manual scorpion collection.  To test this idea, we went to our local drug store and purchased their largest UV flashlight that was marketed specifically for finding scorpions.   It was tiny and the low light output made if difficult to sweep large areas of drainage ditch. 

Clearly, a more manly  UV flashlight was needed.  We needed the Scorpion Stinger...

Step 1: UV LED Selection and Schematic

Since low construction cost was an important feature,  it was decided to use 10mm LED's sourced from Ebay. To create the UV light beam,   It was decided to use 20 pieces of a particular UV LED. At $1 each,  they are fairly affordable.  If you were to use an LED that only contained a single LED emitter, you would need 100 LED's to equal the power of the 10mm LED modules because each 10mm LED module contains 5 UV emitters.


These LED's claim to have the following specs: 
  • UV LEDs with a wavelength of 400nm to 410nm
  • 5 LED drivers per 10 mm LED module
  • 40,000mcd (0.5W) output each 10mm module
  • 3.6 Volt @ 100mA
  • A nice tight 45 degree beam pattern means external optics or focusers not required
The circuit was designed in KiCAD, an awesome free program.

My circuit discussion for the functional blocks can be found on the JPG annotation.

well done ! ...One of the Great Instructables! <br>Well documented and good photos. It's actually practical, too! <br>The cherry on top would be to show a movie of scorpion catching!!
Thanks! I could sure use your vote in the Laser cutter contest! I did shoot a little 5 second video of a scorpion running off... maybe I can find it. Those little buggers know when you are getting in close for a camera shot and they take off and disappear under a rock. They are quick. Video cameras, UV Flashlights, and picking up scorpions do not mix well, especially if they try to run up your pant leg. :)
Been there with contest votes, and know they are hard to extract from folks!<br>You got my vote. Good luck with it.<br><br>Maybe use infrared lighting for the camera, and same time uv for the little buggers?
This is awesome. I had no idea about looking for scorpions this way. :O
Thanks! I've read some of your instructables before. You are very creative and document well! I could use your vote for the laser cutter contest :)
Very nice well documented build. You got my vote.

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