What's the Coolest Thing You've Ever Built?

Josh Lindenmuth asks: "In high school I was involved in an engineering competition where we needed to create a machine that could move 100 lbs of groceries from a disabled person's car up and down a set of stairs, and then into their kitchen. It was probably the coolest thing I ever built (there were only 3 of us on the team), even though the wooden treads started splintering halfway up the stairs (we didn't have a metal shop, so it was made entirely out of wood, spare boat parts, and conveyor belts) and then it completely destroyed the stairs on its way down (it weighed over 300 lbs)." That's Josh's story, now he wants to know yours. Cool computers, cars, hovercraft, handheld devices, fusion reactors — what is the most interesting gadget, product, or device that you've ever built on your own?

I hate to (have to) ask...

[davecrusoe]

but... how could a 300 pound machine completely destroy stairs... because of its weight? For what it's worth, I imagine that many of us weigh > 300 lbs when carrying our MASSIVE computers upstairs from the car... or 130 pounds of Ramen noodles... or about 60 of the lastest video games... or... well, you get the point.

Re:I hate to (have to) ask...

[stevo3232]

It's all in how it's going down the stairs. A 300 pound person walking down the stairs and barrelling down the stairs are two different things.

Re:Igloo

[Bastard of Subhumani]

I really did build an igloo! Three of us slept in it overnight. It was surprisingly comfortable.

Re:My Son

[Ucidalin]

Well, last time I checked, there was no building in child making. You pretty much just donate a seed and fertilize it, then just nourish and protect it. Nature does all the building here. Maybe when DNA research advances, you can actually build your child. Till then it is Nature that does the building. A woodchuck would chuck as much wood as a woodchuck could chuck if a woodchuck COULD chuck wood.

Sferics Recorder

[Aging_Newbie]

In high school my junior year ('65) I built a system that displayed electromagnetic radiation from lightning strokes on a CRT. I had little money so built it from old TV and surplus parts. Three foot loop antennas oriented N-S and E-W picked up the signals and displayed them on a scope tube. The whole thing was vacuum tubes, I think around 8 or so. That was pretty cool but not all I wanted. The next year, I contacted IBM, who helped me with schematics of flip flops and other logic implemented with transistors (wow!) and I made a recorder that would write the signals on paper charts so I could correlate them with the next day's newspaper reports of distant storms. The recorders were constructed of old speakers with the cones removed but the voice coils still in place, recording pens on long arms that magnified the motion of the voice coil, and a coffee can driven by a clock radio movement that moved a sheet of paper under the pens every 12 hours. I ran it a whole year and tracked storms as far away as Lousiana from my house in Minnesota by the lightning they produced. It was pretty neat. I also tracked some tornadoes that I recognized by the almost continuous lightning they produced. It was lots of fun and I won some awards at the science fair.

It also got me a college scholarship to get into a physics program, which I wouldn't have gotten any other way. So, now you know how I came to be spending my Saturday afternoon typing into Slashdot.