Resealable (Cat Proof) Magnetic Window Insulation Tutorial | Everyday Crafty Goodness Before I got Elliot the Cat, I used to put up those plastic shrink wrap sheets over my windows (the kind that came with double sided tape). They worked well but I had to redo them every winter and I couldn’t open the windows without ruining the plastic film. I stopped putting up the plastic window insulations after I got Elliot because he tore them to shreds. This year I came up with a cat proof way to seal in the heat … take a look! 1. 2. 3. 4. 5. 6. 7. 8. Now repeat with all the windows in your home. These magnetic window seals are reusable and you can put them up and take them down quickly. The air between the window and the vinyl is definitely a lot colder than the air an inch away from the vinyl. Whew, so there’s the magnetic window seal tutorial … it’s my very first tutorial so please feel free to leave a comment if I’m not clear in any part. Stay warm and pay less for heat! Like this: Like Loading...
Build Your Own Bicycle-Powered Battery for Emergency Power How to Mooch Off of Your Friends (Without Them Ever Knowing) Free/Discount Power LED Backpack Lighting system There have been many LED instructables, so I will mainly focus on what's different about mine and leave you to fill in the details by reading elsewhere. I won't go into calculating resistor values, series vs. parallel, or things like that. Partially because I did this a while ago and don't remember some of the stuff. First, the rationale: I don't want lights on my bike because they're theft magnets, are more fragile, and more cumbersome. I used two Luxeon Rebel Stars (145 lumens @ 700mA) for the headlights, and two Luxeon III red-orange side emitters for the tail light. I went the resistor route instead of using a buckpuck, which I somewhat regret.
Using AC with LEDs (Part 2) - and make this handy counter light. The simple and obvious way to get hundreds of volts down to a level to operate a LED at 20mA is to put a resistor in series with the LED. To find out what values we are talking about, we'll use the peak value of 110v, which works out to be 150v for our example (it'll be double for Europeans and Ozzies) 150 / 20mA = 7500-ohms (we should subtract the voltage of the LED from 150v first, but the difference is minor) 7500-ohms? 150 * 150 / 7500 = 3 watts, and that's a pretty hefty resistor. Fortunately, by substituting a capacitor for the resistor, we can get the same reduction on voltage without the (or as much) heat.
Using AC with LEDs (Part 1) The subject transformer was made for many AT&T cordless phones, it is rated for 110v/60Hz and has a 10VAC 500mA output. First, we have to be aware that the 10V rating is known as the RMS voltage, and is the effective average power of the sine-wave. The maximum voltage, which we will subject our LEDs to, is about 1.4 times higher. We can demonstrate this by hooking up our transformer and taking some measurements. The second image shows 10.8 VAC, which the unloaded output of the transformer. Next we add a simple diode with a smoothing capacitor and measure the voltage across it: 14.5VDC. This number is about .8v less than our calculations because the diode has a voltage-loss across it of .8V This is one reason we try to avoid diodes because each one inherently loses (as heat) a bit of power - .8v is 25% of the power for a 3.2v LED. So, we will be using 15.3 volt as the basis our calculations.
Outdoor Auto Woodworking