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Purely resistive voltage dropping will create a fair amount of heat considering the amount of voltage you are trying to "waste" as heat. <p>As an alternative to resistors you could wire 2 or 3 bulbs in series or drop the excess voltage using a zener diode and resistor combination or any co...

If you do use a PC power supply, read the output specs (sticker on side) carefully. Note that very often the 5V and/or 12V supplies do not guarantee regulation until a minimum current load is applied. In other words, it may not be 5V under no load or small load conditions.<p>AT supplies are easier t...

I haven't seen anything exactly like that. You may want to try your question in the Ausio Visual Forum www.avsforum.com there are some hard core couch potatos there who may be able to help you.<p>If your bigscreen TV can take input from a PC you may have other options. A couple of USB video capture ...

The transmitter is a lamp of some sort. It may be infrared or it may be plain white light and a lens. The reciever is a photosensor sensitive to the light from the transmitter. The TX is simply aimed at the RCVR or the door won't work. If the beam is broken, the logic circuit turns off the motor and...

Michael<p>I didn't mean to be so pessimistic in my last post but I do still favor a low-tech solution here. A roll of "No cell phone" stickers (like the no smoking symbol) strategically stuck in visible places, a few "please turn off cell phone" signs by the door, a verbal remind...

I'm glad you want to monitor AC current because DC is a pain in the neck unless you use a series resistor.<p>What you want is a simple data acquisition system. Almost any system with a few channels of A/D would work. Check out this URL http://www.dataq.com/products/startkit/di154rs.htm they have a 4...

I sure do remember Radio Electronics. I started off with it in 1982 and rode it all the way through Elecronics Now and a couple years into Poptronics when it stopped serving my needs. I had most of my back issues until a few years ago when I let someone clean them out based on the 10-year rule (if y...

Michael<p>I suspect that the design of a transmitter of your specification on both the circuit synthesis(theoretical design) and the actual physical circuit design (nevermind the special considerations you need to take in laying out an RF circuit onto a PCB) are well beyond the scope of this or any ...

A bit more on avalanche beacons can be found here:http://www.couloirmag.com/gear/reviews/accessories/beacons99/beacons99.htm<p>I think that the beeping reciever you describe from the movies would probably work like this: The transmitter would be a continuous wave TX at a relatively low frequency of ...

If I read you right, you want to market this ruler and make some $. I know a few teachers and they are all experts at begging for materials and educational discounts, there simply isn't much money in the school systems. Your only chance might be to sell it to an educational publisher or maybe the di...

Seems to me that most digital phones would simply switch over to Analog mode if it couldn't lock onto a Digital tower. You would have the honor of draining their batteries faster though. Perhaps pulsing the jammer output would cause a dropped call as fast as it came in.

What program generated the .CAD file? I find that the design files made by most PCB CAD programs (whatever the extension)are propriatary and can only be viewed in the native program. Generally you may be able to port a netlist or a set of gerber files but not much more.<p>Try these links as a starti...

As you probably have seen from the catalogs you mentioned, BUDD is a popular Brand. Hammond amkes stuff too but mostly industrial.<p>Whenever I am not sure of the best vendor, I turn to a buying guide like <p> www.thomasregional.com or www.electronicssourcebook.com <p>for lists of manufacturers segr...

Check out this link http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=34640 <p>50 piece set of just the right sizes for only $13 and they should fit in your dremel.<p>In case the link fails their item # is 34640-2VGA or search on "micro" I had trouble finding them searching ...

Try rigging a float switch (normally closed)to interrupt the current to the bulb either directly or with a relay. Mount the switch on the back of the licence plate holder or any other convenient location below the lamps. Shield the float and switch from wind and road debris inside a section of pipe ...