Category Archives: Gadgets, Toys, and “Inventions”

A Card “Force” Using Unintuitive Mathematical Odds

“A card force is one of any number of methods used in close-up magic to apparently offer a subject a free or random choice of card, when in fact the magician knows in advance exactly which card will be chosen. This can then be revealed later in the trick.”

Premise: We have a set of three cards, all of which are known to us. We attempt to force a specific card on the unsuspecting participant by instructing them to randomly point at one of three cards, which are all laying face down. Theoretically, they have a one in three chance of picking the correct card randomly. If they point at the desired card, we immediately instruct them to flip it, effectively “forcing” the card on them in one try. If this works on the first try, the trick will be especially impressive. However, if it doesn’t work on the first try, we still have a fall-back method:

If they point at one of the other cards, instead of telling them to flip the card, we pretend that they’re playing a game of elimination and we simply remove the card, instructing them to point again. If they point at the next incorrect card, we instruct them to remove it, leaving one final card: the correct one.

Potential downside: If they point at the desired card on the second step, then the “force” fails,
because when we remove it, the end card will actually be the incorrect one.

Cards used: Ace of Hearts (the desired card), Queen of Clubs, and 8 of Spades

Approximate Results After 2000 Simulations:
Times ended on Ace of Hearts: 1322 (0.661)
Times ended on Queen of Clubs: 339 (0.1695)
Times ended on 8 of Spades: 339 (0.1695)

Click here to run the simulations yourself using javascript

Odds of picking the right card during the first step: 1/3. If incorrect card is chosen on first step, we pretend it’s an elimination game and remove the card, leaving only two cards, the desired card, and the incorrect card. At this point, you might think there is an even 50/50 chance they will choose the correct card, but in reality, the odds of them choosing and eliminating the desired card are still 1/3 because it hasn’t been touched. The odds of them choosing and eliminating the second incorrect card, however, have increased to 2/3. This is unintuitive, but the simulation shows it to be true.

Because of the fact that we know which cards are which, we can effectively double our seemingly low 33% odds all the way to 66% simply by using this card force method.

The only unsolved problem is, how do you handle a dead end where someone chooses the wrong card, and then the right card on the second step?

Drawing a smiley face on the moon

Smiley MoonWhat would you do if you had a billion dollars? I don’t know about you… but I would definitely develop a method to draw a smiley face on the moon. Call me crazy, but can you think of a better legacy to leave behind? Yeah. I didn’t think so.

Think about it. Future generations of mankind would look up in the sky at night, only to see a big smiling face. Wars would cease to exist! How could people even think about fighting with a giant smile in the sky?

Or maybe we could sell the moon one pixel at a time? Like the site did?

Maybe we could use a high powered laser that would burn the dust and turn it black or something… *scratched his head*. What do you think?

Seriously though, what would you do if you walked outside one night and noticed a smiley face on the moon?

Successful Invention #1

One of the things that I always aspired to be when I “grew up” was an inventor. As a child, I would take apart toasters, pencil sharpeners, lawn mowers, and generally anything I could get my hands on that was broken and had some sort of intruiging moving parts. However, while I have come up with a number of concepts of my own over the years, until now there was never any actual follow-through.

Scenario: I have a thermostat in my apartment that I want to control with a schedule. I want to be able to cool down the house at night, but warm it up in the morning so I don’t have such a hard time waking up and getting out of bed. In previous apartment complexes, I was able to use a standard 7 day, programmable thermostat (available from Walmart, Lowes, or your favorite home supply store for around $30-$75). However, the heating system in my apartment complex here in Phoenix uses an old system and is incompatible with virtually all the programmable thermostats out there. I was only able to find one programmable thermostat out there that would work with my apartment’s heating/cooling system, but it didn’t have some of the capabilities that I was looking for. So I am basically limited to manually moving the needle on my thermostat by hand if I want to change the temperature. No programmable scheduling allowed!

Solution: Using a small servo, a mini SSC II controller, and a serial interface to connect it all to my computer, I built a remote controlled thermostat module. The servo is mounted on the wall above the thermostat and a string is connected to the needle. Once I figured out how to send commands to the servo using my computer’s com port, I interfaced it with PHP page on my local web server. I then built a flash-based interface with a draggable temperature slider that would send the proper positioning values to the PHP page. The end result… a thermostat in my living room that can be physically controlled from anywhere in the world over the internet.

Click here to watch a demonstration video clip!
(12 megs in size. Windows Media Player required.)

The Laptop

So I ordered a laptop from ebay about a week ago, despite the fact that the seller said it had “a small scuff on the cover”. When it arrived yesterday, I ripped the box open and dug through the packaging materials in anticipation. I could finally surf the web from my couch!

Eagerly, I plugged in the laptop, flipped open the screen and tapped the power button. As the 8 pound beast purred to life, I pondered all the nifty things I would now be enabled to do. Surfing the web from a coffee shop? Yup. Surfing the web from my car? Yup. Surfing the web at the local gas station? Yup. (Seriously! They have wi-fi!).

A minute passed…

The screen was still blank.

Oh no.

“Well, maybe something’s just loose!”, I thought.

Feverishly, I unplugged the laptop, pulled the battery, hard drive, and memory stick. After that, I held down the power button for a full minute to drain any residual power from the remaining components.
Then, I put everything back exactly the way it was.

“Ok, maybe it’ll work now.”

Nope. Still not working.


Two hours later, I get off the phone with HP’s tech support.

During the course of the call I discovered:
1. The person who owned the laptop before me purchased it only a few months ago in July.
2. My laptop was technically still under warranty and still has 200 days left!
3. I could purchase an extended two year warranty for *only* $249!
4. This extended warranty would cover everything, including accidental damage such as coffee spills or random drops from the roofs of 30 story buildings.
5. HP would have FedEx pick up my laptop on the morrow between 1 and 5 in the afternoon.
6. They would only take the laptop if I bubble wrapped it and boxed it up nicely first.
7. They will ship my laptop all the way to California, fix it, and ship it back to me by Wednesday of next week. All for free.
8. HP hires only Indian/Korean people.

So I purchased the warranty, raising my entire laptop cost to around $1,050. Considering that it’s a laptop with a 64 bit Athlon 3200 processor, 512 megs of RAM, 60 gig hard drive, DVD drive, CD burner, 15.4″ widescreen… I guess I came out ok. Sure, I could have bought it brand spanking new directly from HP for about that price. But I would have only ended up with a 1 year factory warranty that way. This way, I am totally protected against all damages.

Who knows? I might accidentally drop it one month before the extended warranty runs out, and HP would have no choice but to replace it with a comparable (read: better) model because two years from now, they probably won’t have any of these puppies still in stock.

So yeah.

Arkansas and Ebay

Well, quite a bit has happened since I last posted about the fourth of July.

For starters, as of the 10th, I have officially known my girlfriend for a year. Crazy huh?

Oh yeah, and this past weekend I went and visited my family in Arkansas, which was cool. My little brother Samuel has really grown up! I can’t believe how much bigger and stronger he’s gotten. Man, it really used to stink, growing up with 5 sisters and not having a brother to play with. Samuel was always too little to do anything with so I always just kind of did my own thing. But now he’s all grown up and he’s almost as big as I am! We wrestled and he beat me. I couldn’t believe it. Too bad they don’t live closer to me anymore. I think he and I would have a grand ol’ time.

Well, at any rate. ‘Nuff of my rambling.

This evening, Shane and Jared want to go flying again. I’m going to get Zach or Corban to go along and we’re going to fly around Dallas and see what it looks like from the sky at night. I’ll let you all know how it goes.

On a side note, I am liquidating some of my assets on ebay (although I know none of you really care):
1. Tippmann 98 Custom Paintball Gun
2. Tokico High Performance Front Shocks for an 81-85 RX-7

And here are some recent purchases of mine (I’ve been saving up for these for a long time):
1. Denon AVR-2105 Home theater receiver with Dolby Digital EX, DTS-ES, and Pro Logic IIx
2. JBL SCS160SI 7 piece Home Theater Surround Sound Speaker System
3. Coleman 9279F127 12 x 7 Montana 5-Person Tent

Digital Camera

Ok so I finally broke down and bought a digital camera. I got a Sony Cybershot DSC-P73 (Approximately $250 retail). ‘Cept I bought it off of ebay for $142 (plus $15 shipping). The camera showed up on my doorstep literally two days after I placed the winning bid. The camera came new in it’s original box, complete with all accessories such as batteries and cables. I’m impressed!

Without further ado, I present a sample image that I just snapped:

Click to view small version

Click to view big version