Engineering

how do motion detectors work? i want to set up some for my shed, i was told little kids can get past them. any ideas thanx

I'm a second semester Electrical/Computer Engineering student at UWF/UF. I'm very familiar (and happy) with my TI-89. However, smoe senior students and instructors say that HP is the way to go in 'real-world' engineering. Is this really the case? If so, which model should I look into? The HP49G appears to be pretty similar to the TI-89, while the HP48GX seems to be more of what I should be looking for. Any opinions?

Today, I noticed an advertisement for the RICOH Sustainable Development Award. I know that innovated engineering is not exactly my field of expertise, but I was compelled by the cause. It is essentially a project for developing innovations that will ultimately lead to a society with sustainable homeostasis (zero environmental impact). It's not so much the money that I'm after, though I admit that it doesn't hurt , but I'm after the recognition that would come from an award like this one. Here is their link- http://www.ricoh-sustainability.com/ Does anyone have any ideas for a project like this one? Also, I can't seem to find the official rules for the c…

I recently received a challenge/project in which I need to shoot a water/air pressure powered bottle rocket into the air and get it to stay in he air for as long as I can while not breaking and egg that has to be somewhere on the rocket. Here are the rules I received. Material: 2- 2 Liter Soda Bottles (minimum) 4 File Folders Duct Tape 1- Large Egg (App. 70 gr.) **No Metal Guidelines: 1- 2 Liter Bottle for Fuselage No more than 60 PSI of air Total Length, 9ft or less Total Weight, 300 grams or less **No Metal, explosives, or other fuel Rules: 2 Chances, 1 with each rocket Add as much or as…

My radio was producing distorted sounds, but when I brought my hand near its antenna the voice became clear.Can anyone explain the reason?

While searching for info on electrical charge distribution at the earth's surface, I identified an application that uses the earth as a near perfect conductor. http//tdworld.com/ar/power_one_wire_enough/ http://www.stonepower.se/Images/SWER.pdf It is a working application that can't be disputed, but I cannot find a geophysics source that identifies the theory for the near perfect conduction. The pdf article notes that the engineers used 0.05 ohms/km at 50 Hz for the design model. All of my reference sources indicates that earth resistance is quite high. Am I missing something, as it seems the earth conduction is different from earth resistance? Any sources …

I came home today and all of my receptacle cover plates were curled up. Is this a moisture problem or an excessive current problem? We just went through a hurricane and it knocked a hole in the roof and could have screwed with some other things. Any ideas on how to prevent this, or what's causing it?

I was thinking about having 555 driver boards custom made and then selling them alone or in kits. Would anybody be interesting in buying them? Depending on the resistors/cap you use it can be made to do a lot of stuff. Some of the more entertaining uses would be driving a flyback or ignition coil. Obviously having them made for cost a fair bit of money so I don’t want to jump in to this if nobody has any interest. So what do you think? Market or no?

What is an energy efficient method for a robot to climbs stairs? I have ideas for a three wheel design (ripped off from Hannibal). And another design that uses a hydraulic or pneumatic lift (but these seem like a waste of energy). Any ideas? Thank You

in a large scale quarry, cutting and dressing one 2.5 tonne block per 2 mins, how plausable is it to use copper tools?

Here is the URL to our site. It's a bit laughable I know, but we are looking for interested persons in the Milwaukee area. http://www.geocities.com/usmc_1371_3/index.html

How do the X-ray machines work? Do they have a natural scource or do they make them artificially?

i'm building a van der graff generator but i can't put it to work... i think everything is ok, the tube and the sphere (in my case a soda can) have to be closed? (i meant to be no contact with the atmospheric air)

-A Cerle Effects Generator- Can anyone help we find out any infomation on it what so ever.

Ok, I'm planning on building something involving balance. I don't want to reveal it to everyone at this time because I'm acting childish and don't want to give out the idea. basicly, with the segway as an example, i'm trying to figure out how to determine how fast the wheels should be moving (kmh or mph) to keep balance. I've looked at http://tlb.org 's explanation on how he built a segway. This is his basic algorithm: Could somebody explain this to me? I don't need any explination on overspeed or anything like that. I expect my design to be moving alot faster and it is oriented where it won't matter. So all i want to know, is based on information g…

what materials does infrared not go through?? thanx

Ok, my uncle works for a heating/cooling company. He installs heating/cooling systems. He wants to take a microwave oven to work to cook hot pockets for lunch. Is there a safe way to ghetto rigg the microwave to one of those adapter that fit into the cigarette lighter in cars? Is ther and adaper like that that has a plug in on it?

Hello, Recently I participated in a Quiz competition held at my college.The subject for quiz was electronics.I made till the finals but came third. Well one question that is still bugging me is this:: What are the four terminals of a FET? I just know the basic funda of FET....and know the three terminals..but where on earth the fourth terminal comes from? I asked this question to my teacher, but she said she will explain in detail when she will start FET chapter later this month. I am curious to know the fourth terminal Can somebody please explain? Please give me some links to good FET tutorials.

I have a voltmeter (multimeter); how can I use this to test AA and AAA batteries? If I am correct, simply touching the leads of the voltmeter to the contacts of the battery would almost always give me a reading of 1.5 volts. I think by adding a resistor, I can get a correct reading. How do I calculate what value resistor I need?

If a tube with spiral cut inner walls was filled with water and another tube of a smaller diameter with a spiral cut outer wall was placed inside the tube, but not touching the inner walls of the larger tube, and then spun... would the spinning water be able to move upward... against gravity?

A drill pump uses rubber flanges to create suction in order to draw water into it, through a garden hose and then expel it. It is a simple design but the friction caused by it being airtight makes it extremely hard to turn. If I used a smaller diameter hose, would it need less suction to draw and expel the water?

Hey everyone this is my first post, thought id throw in something fun for my first one so heres one of my photo threads ive put on other boards In a moment of mental abstraction this morning i decided to put the batteries back into my furby to see if it would still remember its mum. It was alright for about 10 minutes, singing, laughing and being genuinely annoying, nothing unusual there. Untill it seized up and started to BUZZ extremely loudly. I remembered a website i once saw, detailing how to disembowel your furby and have a look how it works, so i resolved to do so. Here is a step by step guide showing how i messed with my favourite electronic m…

I have a few questions: 1) Are there any equations for architecture, i.e. a dome can withstand x joules of force, etc. 2) How do I make a dome??? I know its an arc turned 360 degrees, but how do I make one??? How do I make a perfect arc? What is Roman cement made out of?

Can anybody help me work out how to make a steam generator.

Is There Any Electronic(s) Engineer(s) Here? Through years of hardwork & trials I have successfully designed/Invented the Radio Transmitter circuit shown below. BUt this transmitter can cover a range of 100-150meters(with an antenna of hight 3-5meters) only, and a frequency range of 90-103MHz(by adjusting the rheostat or the number / size of the copper wire inductor). I therefore need help on how to Increase the Power of this Transmitter by at least 10 times such that it can cover >1Km(1000meters). Thank you. DiAGRAM TO BE ATTACHED:Usage (Not linked)