Thursday, June 7, 2007

The Tennis Ball

So, Before I start... Don't tell me that I'm silly, or that this is ridiculous or that I have too much time on my hands.... The first two are accurate, then third one is not.

So... Here's the story. Last year when we moved into our home, and finally had a garage again, my wife asked my to hang a tennis ball in the garage to help her find the "Optimum parking spot" Essentially she wants to park as close to the overhead door as possible so we can still navigate around the workbench etc. After a little bit of chuckling at the stereotype of Women's ability to park, and after I good charlie-horse courtesy of my wife, I obliged her request. I took some twine, put a knot in the end; jabbed the knot into the ball with an awl, and hung the ball from the rafters.

People enjoyed this ball so much that we couldn't have company without the guests punching or kicking the ball. Within hours I was readjusting the ball, within days I was replacing the twine. After that Every time company came for a visit, I was readjusting and checking the location of the ball. (We didn't want the car's trunk under the door so a constant eye needed to be kept on the ball. Finally somebody hit the ball and the twine got tangled in the chain drive of the door opener.

I began to scheme. A sensor on the ground that would light up a light on the wall... An infrared sensor that beeps. This had to be a DIY thing, and had to be something that wouldn't need constant care and feeding. Lastly It needed to be done with items on hand.

What did I come up with? A tennis ball. But not on a rope. It's a ball on a stick. Doesn't that sound dorky and simple? So I needed to accessorize! I have 200 LEDs at home.


So I started digging. I needed small "Stick like conduit" I found some plastic tubing at my parents' place. Too short but otherwise useable. The conduit wasn't very straight, but enough to do the trick. I decided to route some wire through and Plastic weld a few pieces together. I drilled two holes in the ball. One facing the car's windshield and the other on the top. I then fed the wire through the ball and then soldered 330Ohms worth or resistors on and then soldered a bright blue LED on. The LED was then pulled into the ball and hot glued into place. I did the token "Burn your finger on the the glue gun"

At this point I was giggling like a mad scientist. The neighbors must have been wondering what I was scheming...

I plugged the other end into a 9V AC/DC adapter I had laying around and the LED lit up. Now What?

Okay. Hang the "stick"... But what purpose does the LED serve? Hmm.. I know make the light light up when the car touches the ball showing you've hit the perfect spot.
Once again, I thought what can I do here. Ahh.. Yes.. A washer and a cotter pin. the "stick" moves, the washer touches the pin and the contact is complete.

Well into hour two of this project, I was frantically rummaging through my collection of cotter pins. I tried several, none seemed to do the trick to my satisfaction. I soon realized this was because the pins had zero elasticity to them. So this meant that once you contact the stick with the car, the stick flexes. If a person comes up to the stick with a swift kick, it'll break. I didn't want to be fixing this contraption. Building it was crazy enough thank you very much. So I thought of something with Spring to it. Sheet metal, a piece of Automotive antenna or something like that. I searched for an actual spring, but only found one and it was way too stiff. Then it dawned on me. I let out a Dr.Jekyll cackle and bolted into the house. I needed to make a sacrifice. I found my subject in the form of a "Vendor" corporate pen from my employer. I dismembered the pen (R.I.P), tossing all but the spring . I then soldered the Spring to my cotter pin and Voila! A working switch.

Now to mount this thing. I took some wood, put a nail through the "Stick" and mounted it while still allowing it to swing like a pendulum. I then mounted the switch to the top.

All finished. and it works fairly well. I need a slightly longer and stiffer spring to prevent the ball from bouncing off the windshield when you first enter, but otherwise it works very well. The last thing I will do is hook up the power to the Door opener light so that when the time delay light goes off in the garage, the LED does also.

So Do I have too much time on my hands? Definitely not, but something compelled me to put all my chores aside for the 2 hours to build this incredibly useless contraption. But I bet it's the only one....

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