Instructables
Picture of How To (Not) Hack A Night Light

The road to hacker prowess is paved in stillborn experiments and bloody pieces of failed projects. From these failures we learn patience, determination, how to cuss, and of course, what not to do. The following hour of programming details one such disaster;

How To Hack Together An Adjustable, Dark Activated, AC Outlet Powered, Cold Cathode Tube, Night Light
 
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Step 1: Gather Parts and Accessories

Picture of Gather Parts and Accessories
modware003.gif
See that Modware - Windowed Side Panel and Mod Kit over in the corner? We bought that a few years ago in the heyday of the PC case modding fad and never used it. Time to wipe the dust off. Take out the 12" Neon Cold Cathode Light Kit and the Case Cutting Tool, throw the rest away. The cathode kit includes the light tube itself and a voltage converter (black box thingy). We won't be using the cutting tool in this project but you never know when you'll need some crappy tin snips.

Rummage through your junk box/drawer/closet/basement and find a suitable AC adapter. We'll go into how to pick the right adapter a little later.

Also in said junk, find a transistor, a potentiometer, resistors, and a photoresistor. Don't get too caught up in the values, I have a feeling we'll be replacing these with Radio Shack parts soon anyway.
jetflyer133 years ago
i do believe the "black box thingy" is called a ballast lol
angelaice124 years ago
if ur trying not to hack a night light then just let it be ><
theIdeaMen (author) 5 years ago
I appreciate the encouraging words. I was worried my jovial self-deprecation would be mistaken for genuine disgust. In any event, I had a ton of fun on this project and learned quite a bit.
PKM5 years ago
I haven't laughed out loud at an Instructable in a while.. this was classic. Step 4 especially :)
yes I'm juvenile, sue me

This reminds me of building my own ball mill- it went through four radically different designs, smoked two wall transformers and a piddly electric motor. The process of failing teaches you what works, however, which is always an invaluable lesson.
gmjhowe5 years ago
Well, at least you gained experience, and no doubt you enjoyed making it!
Rob K5 years ago
Cheaper to go with the night light.

Also yellow and red make 7.

You can use the 5v as a ground from 12v. http://www.cpemma.co.uk/7volt.html

nixiebunny5 years ago
That's a fine project, I wouldn't call it a failure. I'd recommend a few small changes to deal with the instability. It's better to use a real voltage comparator, the LM393, when you need to compare voltages. Op-amps aren't designed to run open-loop like that. Add a >1 megohm resistor from the + input to the output for positive feedback to achieve hysteresis. Put a bypass capacitor across its supply leads to keep it stable while switching. Also, having to spend money on this project just means that you haven't stocked your workshop with enough thousands of dollars of inventory. My shop holds everything needed to build this, but I've been collecting junk for 35 years.
cyrozap5 years ago
Wow. $46.95. I'm honored to learn from your mistake. I'm just glad it wasn't me. That's pretty cool, though.