Ask HN: Your biggest non-technical hack/discovery

https://news.ycombinator.com/item?id=875754

by kyro • 17 years ago

48 68 17 years ago

news.ycombinator.com

Try to stay away from coding hacks as much as you can, which is what I meant by technical. I'm talking about social, mechanical, etc. Should be interesting, entertaining, and enlightening to hear about all the clever real world hacks you guys have come up with.

Also, if you have several you'd like to share, go for it.

jacquesm3• 17 years ago

Building a windmill and powering my house with it ? (I guess that has mechanical, but it is also technical, hard to be 'mechanical' without 'technical').

Not sure if this qualifies as a 'hack', but when abroad and stopped by the police I suddenly only speak dutch. That seems to reduce the interest level considerably. Saved me a few fines by cops playing the 'fleece the tourist' game.

rjett• 17 years ago

Does your windmill provide 100% of the power needed for your house? If so, how big is it and how much did it cost to build?

jacquesm3• 17 years ago

I'm no longer living in Canada, where I had this set up. Under normal conditions the windmill would be close to 60% of the power required for the house, the rest was solar.

We did just about everything we could to conserve power though, one of the lessons you learn fastest when working with renewables is that it is a lot easier to save a Watt than to generate one.

The machine was a 16'er, or about 5 Meters, so a swept surface of 18 square meters or thereabouts, it cost a small fortune to build because I was planning to make it in larger numbers. Designed power was about 2.5 KW, it came out a bit less than that, mostly due to a slightly larger air-gap than what I had planned on (the plasma cutter nozzle used to cut the stator laminates was wearing down, and cutting with a slightly larger diameter jet than planned).

The design is far from perfect but for a first try at a variable pitch machine it worked pretty good. It survived several major storms without failure, we only took it down because we emigrated back to Europe. It's laying in pieces on the garage floor waiting for better times.

edit: the only way to get 100% of the power for your house from the wind would be if you would consent to being without power every now and then. After all , the wind only blows so much, and when it doesn't you'll need to have either enough power stored up in batteries or you'd have to have an alternative source.

What people do to get to the economical equivalent without using batteries is if their grid operator allows it do something called 'net-metering', this allows you to pump your excess power into the grid and back out again when you need it for the same price.

The whole uncoupling of network and electricity production is seen by plenty of people in the renewable energy scene as a way of discouraging net-metering, after all, if the 'base' rate per KWh is already quite a bit just for transport then they can afford to give you a crappy price for your excess power, and charge you twice for the storage and retrieval of the power.

dryicerx3• 17 years ago

Lockpicking count?

kyro5• 17 years ago

Sure it counts. Any particular tools/methods you use?

czcar• 17 years ago

ahh, the misdirected adventures of my teens, lock picking always had a sense of excitement to it. Use to frequent totse.com a hefty amount, "temple of the screaming electrion", always thought it was an awesome name.

dryicerx3• 17 years ago

Dremel picks with wiper blade inserts, saw blades, and hacksaw blades. Hammered/flattened nails make for great toque wrenches (alternative is the flat metal clips on pens).

kyro5• 17 years ago

A few of mine:

-In college, I found that the card readers to open the gates into the faculty parking lots, and into the inner ring of the campus, didn't really check for anything... other than a physical card in the slot. So 3 years worth of free parking close to campus was definitely great.

-I worked at a franchised sub shop for a time, and the music discs we were required to play were pretty horrible. Listening to Fallout Boy got really annoying after the 400th play or so. I decided to pull down the player, which could 'only' play the cds sent to us, to see if there was anything I can tweak. I found a series of 16 pins on the back, and with some googling, discovered the position to place the connectors so that I could play anything. It worked, and in no time, I turned the place into a hip hop club, making sandwiches to the tunes of Jay-Z and the like.

-Slamming the coin slots on games at arcades, dislodging a few coins.

-After taking a hot shower, I'll turn the knob so the water gets super cold for a few seconds. It's a nice way to get me going after a nice relaxing hot shower.

flooha2• 17 years ago

I do the show thing too. I'm not sure how healthy it is, but I always feel great after doing it.

chrischen• 17 years ago

Fiddling my ID card into the lock in the door of any room in my school would eventually unlock it. I got into a room after the teacher locked it for lunch once (we leave for lunch and come back after).

zackattack3• 17 years ago

A Combinatorial Proof of the Summation Identity (i=1,i->n,i) = n(n+1)/2

http://img.skitch.com/20091012-mt5p22p1fxi3s1y32wqid49pwm.pn...

Zachary Burt, University of Chicago, 2007

Assume n people are in a room and they each shake hands with every other person. This constitutes n(n-1)/2 handshakes: each person shakes hands with every other person. The number is divided by two to account for double-counting the handshakes.

The sum of handshakes can alternatively be computed by summing the number of unique handshakes made by each person: person 1 shakes n-1 hands, person 2 shakes n-2 hands (for he has already shaken hands with the first person), and so forth, until person n-1 shakes only one hand: person n has already shaken hands with everyone else. This can be expressed as: n-1 + n-2 + n-3 + ... + 1, or, through the commutative property of addition, 1 + 2 + .. + n-2 + n-1. This is conveniently expressed as the summation (i=1,i->n-1,i).

We know that the summation (i=1,i->n-1,i) is equivalent to the expression n(n-1)/2. If we replace n-1 with n, this is the same as saying (i=1,i->n,i) = n(n+1)/2. QED.

anamax2• 17 years ago

Girls like sex and want to have sex with me. All I have to do is express interest and not piss them off until afterwards.

Generalizing "afterwards" makes relationships possible.

Women are girls in many respects.

zackattack3• 17 years ago

I can't believe how long it took for me to internalize this

fogus• 17 years ago

I once worked at a car wash were most of the employees were out on work release. Anyway, the days were long and boring so I took the time to devise a way to get free sodas out of the vending machine. I was not interested in stealing soda, as I hated it, but only in figuring out how to do so. I eventually did so. I was so proud of myself that I decided to show one of the guys that I got along with pretty well. When I came back few days later the machine was completely empty and was never again able to provide tasty beverages for very long. Eventually the owner of the machine caught on and removed it from our site. I was very naive.

kyro5• 17 years ago

Yeah, a similar story here. Pumping the lock with your finger would pop it out, which, after unscrewing the bolt, granted me access to a world of soda beverages.

Shooter2• 17 years ago

I once went to a conference that was held on an Arizona college campus during summer session. The school kept having soda and vending machines disappear periodically. It turned out that guys from the local tribe were taking the entire machines back to the reservation in their trucks, using them until they were empty, and then lugging them back to be refilled. I'm not sure what method they were using to get the soda out without paying, but they finally caught some of the guys using video cameras. I think it was all done more for the excitement than the soda...and also maybe to make a statement of some kind. (I can't imagine hauling one of those big machines around for the soda it would hold.)

zackattack3• 17 years ago

For many years, jamba juice was running a promotion: buy a $25 gift card, get a free jamba juice. So one day I bought a gift card, got my free razmatazz, and was about to head out on my way when I doubled back.

Me: "I'd like another $25 gift card please."

Cashier: "That will be $25. What is your free smoothie?"

Me: "Peach pleasure."

And then I would pay with the previously purchased gift card, creating an infinite loop with a sunk cost of $25. I was only once refused. I netted at least 50 jamba juices for me and friends..I hope to incorporate this into a screenplay some day.

jacquesm3• 17 years ago

That should teach them about recursion :)

Brilliant to spot the loophole on the spot.

thomaspaine• 17 years ago

I did this with Blockbuster a few years back. I believe it was a free $5 gift card for each $50 gift card you purchased. Most stores I've seen now have a policy of not letting you buy gift cards with gift cards.

ax0n3• 17 years ago

You win.

abalashov2• 17 years ago

They did not arrest the recursion by specifying that the free jamba juice offer did not apply to gift card purchases?

dolinsky• 17 years ago

while cute, i'll call crap on this :) they specifically make you buy the gift card with a credit card, not another gift card.

nfnaaron• 17 years ago

I hacked a skydiver once.

I was a civilian/sport/fun/non-military jumpmaster in the eighties. Taught/supervised skydiving students from the second jump on. Sometimes sat in the plane and supervised/critiqued, sometimes jumped out with them for some task they were learning that involved another person in the air.

One student was having trouble staying stable when he left the plane. Tried everything I could think of, he was just tense and maybe a little tunnel visioned. He really wanted to succeed, and I really wanted him to.

However the student leaves the plane (there are many ways), you or the student would typically say out loud "ready, set, go!" and go on "go." Regardless of how he left the plane, he tumbled.

As we went up once again, near the end of the day, I had no idea what to try except some variation of what I/we had always done. We got to altitude, turned on jump run, and he climbed past me to stand on the step outside the plane. I still didn't know how to help him.

He got in position, looked in at me, and almost without thinking about it, rather than saying ready set or whatever, I took a big, obvious breath, slowly let it out in an exaggerated, relaxed way, and casually pointed at him.

Beautiful exit, and he had a big smile when we met on the ground. Helping that guy through that was one of the most satisfying moments in my life.

thesnark2• 17 years ago

I made a portrait of my girlfriend out of dice.

http://www.elusivesnark.com/2008/11/carolines-dice-portrait....

dylanz• 17 years ago

Wow... this is beautiful!

stcredzero• 17 years ago

Not to take away from the accomplishment, but I think most of the credit goes to the model's parents. (Intended spin is as a compliment.)

MikeCapone• 17 years ago

Good job!

Where did you get the idea? Did you come up with it yourself, or is it something that was already floating around?

thesnark2• 17 years ago

I got the idea from this page:

http://4c.ucc.ie/~hcambaza/page5/page5.html

The number of dominos I would have needed would have cost too much, so I decided to use dice instead.

colbyolson• 17 years ago

I would love to do something like that, but the weight alone is too much for drywall/normal walls.

Really cool idea though, I'll have to remember this one.

iigs• 17 years ago

It's not a specific hack, but it has given me the same feeling, something I keep discovering: It's just a bunch of rules. Learn the rules and you understand it.

We've probably all seen it with computing; it looks mysterious from the outside but learn the logic and you can make it go.

Fixing cars is the same way (fuel, air, spark). Circuit design is the same way (a few types of component, logic gates). Power engineering is the same way (W = V*A, wire's got to be big enough). Music is generally the same way (very math-y in both the time and frequency domains). Dating is pretty similar (statistics play a different role here, but you can do well enough here "by the book").

We're currently learning that raising a child is the same way. Diaper, hungry, tired, hot/cold, {colic, teething, other age related issues}, doctor.

ax0n3• 17 years ago

I agree wholeheartedly. My best hack? I can figure out how almost anything works, usually very quickly, by probing for rules. It works for almost anything: mechanical, employment, electronics, etc.

Good for social engineering, too. :)

jjs2• 17 years ago

A corollary: most ostensible rules aren't the real rules.

Knowing the difference is a form of power.

thesethings2• 17 years ago

* Cooking: Ramen can be used not just for soup, but for stir-fry.

* Travel: Any supermarket is your fee-free ATM. (cashback) (US)

* Travel: In the middle of your urban trek and have to pee? Hotel lobbies usually have clean, open bathrooms. (Specifically talking about the one you're NOT staying at, when you're wandering for 10 hours in a foreign city, and don't want to go all the way back to "base.")

* Travel: Hotel lobbies often have free wifi.

* Cooking: Peel an orange inside the produce bag. Makes for perfectly dry, not messy, not sticky experience. (your fingers can poke through the skin and tear it, and it doesn't tear bag. Magic.)

* Travel: I have so many Priceline and Hotwire strategies, but the short version is: use these sites to book hotels.

abalashov2• 17 years ago

Supermarkets require a purchase to provide cash-back, do they not? That would seem to amount to some sort of fee, even if it's a lot smaller (e.g. a 50 cent pack of gum).

EDIT: I suppose I am referring to precisely that aspect of them which would otherwise be "ATM-like" - namely, that the function is to dispense cash on demand, and that the fees in question would otherwise go solely toward paying for the privilege. Cashback is a nice way to stock up on hard currency, but it is technically a side effect of making a purchase, not an ATM, even though in practice the side effect does not entail a "fee" in that you meant to buy whatever you're buying regardless.

thesethings2• 17 years ago

Right. But purchasing something at a store like this when I travel is in no way forced for me.

I find my friends and I go to grocery stores/drug stores even more often when we travel than at home. You have no stock of stuff like when at home/work. You're constantly grabbing a drink/a snack things to take back to "base." You often have no refrigeration, so that means more, smaller trips to the store, too.

seven2• 17 years ago

During chaos communication camp (lots of hacker do camping) 2003 in Germany was one of the hottest days recorded since $longtime. Normal fridges where not allowed on the campside, because of the heavy power consumption. So I built a fridge out of a box, a towel, plastic bottle and a fan. Worked like a charm. Most other hacker who saw this were like: 'Damm, I told my friends this would work...' Execution is all! :)

On the same camp, I talked Emanuel Goldstein into signing and selling me the last VHS of Freedom Downtime that he had broad over from the US and was intended to be a present for the camp organizers. ...Or did he talk me into buying it...?

kyro5• 17 years ago

Wow, cool. How did you go about assembling it?

brought

seven2• 17 years ago

Nothing big or special. I punched some holes into the bottle and made it drip onto the towel that was wrapped around the box that contained our snacks etc. Had a fan pointed to the towel. That is all. Evaporative (heat) loss is the keyword.

What made me remember this, was the fact that I was in between about 2000 hackers who probably all thought about this.. but that I was (afaik) the only one who actually did it.

In Nigeria they use more or less the same trick to build simple air-conditioning. Imagine it as a wood box open on two sides with a lot of small brittle branches inside. Water dropping into it. And a fan blowing on one open side.

btw: although mixing up brought and broad is something that I could have found myself and is a result of being sloppy; I always appreciate input on my writing. As English is not my native language, I would guess that my grammar sucks more than my spelling. :)

tomsaffell• 17 years ago

When WilliamHill.co.uk (a gambling site) launched in the UK they offered a promotion: a 50% rebate on your first stake (max 50 GBP)

The hack was simple, and spread like wildfire on campus:

  Place a GBP 100 bet on a basket ball game, at odds of 1:1.9. Get GBP 50 rebate.

  Get a buddy to take the opposite bet, at GBP 100 (they get GBP 50 rebate)

  One person wins 0, the other GBP 190. Split the 190, both parties are up GBP 45. 

  Repeat as many times as you have credit cards numbers (new registrations each time)

Lots of people pocketed hundreds of pounds in ~1 hours work, risk free, and we were students, so it was good money. I think it was 1999, maybe 2000.

bhseo• 17 years ago

Nice combination of bonus abuse and sportsbetting arbitrage. You can still make money in similar ways, although online gambling operators have tightened up the last few years.

vital101• 17 years ago

The remote for my car has a very weak signal strength, so sometimes when I forget where I park I place the remote underneath my chin and press up. My head (skull + fluid) acts as an antenna and voila! There's my car!

You might look like a fool doing it, but I promise it works!

kyro5• 17 years ago

Your skull works more as a satellite. :P

And yeah, definitely does work.

noonespecial2• 17 years ago

If you hold a coin halfway into some older parking meters for a while, it will think its slot is jammed and registers "out of order." Most cities won't ticket an an out of order meter. Free parking. All day.

anamax2• 17 years ago

> Most cities won't ticket an an out of order meter.

"Most"? I haven't seen a parking meter in years that without "tickets issued at broken meters" on the label.

dryicerx3• 17 years ago

Chemistry hack.

Distilling Alcohol. I wasn't of age at the time, actually was still in high school, and had a hard time getting alcohol, so I decided to make it my self.

Designed and built a reflux still with embedded temp sensors, a condenser, and one-way air locked gasoline containers for fermentation. I used sugar and yeast to ferment giving me ~10% abv, then ran it through the still 5-6 times to get ~90% abv... it was rocket fuel. I also sent the final samples to a chem student I knew to test for methanol as a precaution. Finally filtered several times through activated carbon to get any final impurities out.

It was the best vodka I've ever had so far, no burn and extremely pure ethanol. I only made a handful of batches before the excitement of it ran out.

noonespecial2• 17 years ago

Any kid smart enough to distill his own booze and smart enough to check it for the "makes you go blind" part (using a method other than the friends at a party test) should be exempt from the "drinking age" requirement.

jjs2• 17 years ago

... and, technically, is. ;)

gstar• 17 years ago

That's incredible - friend of mine and I did exactly that, but in Australia rather than Texas.

We rather over-specced the reflux column (it was about 1m tall, copper, and ran a water jacket pumped from a swimming pool) and we even asked a friend to put samples thru a mass spectrometer to make sure we weren't drinking methanol.

Never thought of it as a hack though, just a cheap way to get booze.

We flavoured it with oak chips and watered it down. Great hackers think alike? :)

keefe• 17 years ago

Human beings have a nearly infinite capacity for self deception. I am not a special, unique exception. I must be merciless in my self observation. The only way forward is to look at where I am and make a simple, realistic plan to take me towards my goal. Underestimating cost in time, effort and money leads to failure.

Shooter2• 17 years ago

I made all of the public area lights at a major hotel and convention center strobe for about an hour during an international science fair. The hotel had a huge glass atrium with elevators and several thousand bulbs, so it was quite a spectacle. It looked like a single huge strobe light had landed in the city center.

It made the news, and I won our (informal) pranks contest for that year. I felt it mostly made up for my loss the previous year (the shaving cream dipped in liquid nitrogen and then packed into a competitor's car was a poor showing, prank-wise. It was unoriginal, it ruined the upholstery of the poor car, and it wasn't as dramatic of an effect as one would think for the trouble. Too much of the shaving cream never expanded after can removal and thawing.)

louislouis2• 17 years ago

It was the last year of college, my student card had only 2 months left before it expired. I deliberately lost it and got a replacement which extended the expiration date to 3 years more since new cards were in for next years batch of students. Needless to say I've enjoyed the student discounts all this time.

Hacking Bus Tickets: I was a poor student at the time and 'all day' bus tickets were expensive for me. After 1 week of paying full prices, I had collected enough tickets to duplicate the fonts using photoshop and print my own tickets :D

Coke Machine: At school there was a vending machine where if you pressed the coke button multiple times and fast enough, it would give u 2 cokes for the price of 1.

School Passwords: I was 14 I think, coded up a basic popup box in VB saying 'Please verify your username and password', the input was sent to a txt file and there was a nice little Netscape Navigator icon to make it seem legit lol. I had the .exe running on startup on maybe 2-3 computers. Over 1 week I had hundreds of passwords including the network administrator pass. :D

jrockway• 17 years ago

I think I did you one better. At my high school, the student computers in our dorms (yes, a weird high school) were on the same network as the computer lab computers. To log onto a computer lab computer, you put in your username, password, and the domain name (STUDENT). We set up a computer in our room named STUDNET and changed a few login boxes in the computer lab to log into STUDNET instead of STUDENT. Several hours later, we had several accounts. Oh Windows 98, how I love thee...

The printers were also on this network. They were all HP printers, they all had the control port open (9001?), and they all had the a DNS name in the form of "...-printer.imsa.edu". A brute-force search of our IP space gave us the IP address of all the printers, and a quick shell-script later, the printers' ready message became "OUT OF WATER" instead of "READY". Every printer on the entire campus, all at once.

Oh, the chaos this caused. Upon walking into the main building, several teachers immediately just had to show me this weird message on the printer. "The one in my office is like this, and so is the one in the computer lab. It's so crazy!" I especially loved watching several PhDs in the math department calling HP to ask where to put the water in. People were talking about this for months, and I don't think anyone ever figured out that it was me.

So yeah. Changing the ready message on HP printers is my favorite hack, and it still probably works.

louislouis2• 17 years ago

haha, nice hacks indeed! The following week you should've changed it to OUT OF BATTERY

grizzydot• 17 years ago

In college my friends and I would go to the driving range a lot. It was a 3 tier range with a golf ball dispenser on each level, all networked together. We figured out (by chance) that if we swiped our range card and then quickly selected the bucket size of range balls, it would dispense the balls before it updated the entire system with the new dollar amount that should be on the card. So we basically got back the cost of the card (~ $20) the day we realized the hack just by swiping over and over (a large bucket was $12). All in all we got around $400 worth of balls before they put in a new payment system.

Mz3• 17 years ago

I guess my biggest hack is getting myself well and off all medication with a condition where the typical answer is drugs, drugs and more drugs (plus surgeries) until it kills you.

Life is chemistry. Knowledge is power. But many people seem to think only drugs are chemistry and power. <shrug>

Edit: Secondary related hack: Managing to share information about what I've done without getting myself thrown off any of the health forums I belong to, in spite of routinely inspiring controversy, outraged reactions, and open hostility.

Tichy2• 17 years ago

Please tell the tale

Mz3• 17 years ago

After being bedridden for 3 1/2 months, I was diagnosed in May 2001 with "atypical cystic fibrosis". My doctor informed me "people like you don't get well -- symptom management is the name of the game". But I have two sons. Since it is genetic, they tested both of them. I told them which child had it and which didn't before they ran the test. My oldest has the same diagnosis I have and had not been on antibiotics for over three years at the time of testing. So when I was told "people like you don't get well", I replied "It may be true that I will spend the rest of my life fighting off the next infection, but This particular infection has to GO as it is killing me." My doctor physically took a step back and looked like I had slapped him in the face.

I spent the next five years trying to figure out what we were doing right that my son was so healthy and talking to people in the alternative health scene who seemed to have some clue. I gradually made changes and developed a mental model for what was going on. For that initial five years, I intentionally avoided joining any online CF forums or otherwise making any strong connections to the CF community. I didn't want my analysis of what was going on to be contaminated by the clearly failed current mental model for what is going on with this condition and how it 'should' be treated.

After five years, I began joining CF lists and forums. Most people on such forums have enormous difficulty believing that diet and lifestyle can do anything meaningful for their condition. Most of them are desperate for A Cure but they seem to all be waiting for a purple polk-dotted dancing, singing pill that will cost gajillions of dollars and have an eight page fold out describing the horrifying potential side effects. Eating right and giving up a few pleasures of North American Affluenza apparently seems to them like A) it can't possibly work and B) the prospect of giving up their couch is more mortifying than the prospect of having their lungs consumed by infection until some doctor decides to cut them out and replace them with the lungs of some perfectly healthy person who died tragically young in the prime of their life.

To each his own. I'm very happy (and comfortable) without a couch, thanks. As of this summer, I am 100% drug free for the first time in nearly nine years. My son has been drug free for close to three years.

flooha2• 17 years ago

I'm not really sure if this qualifies as a "hack". A friend and I were riding dirt bikes through the forest and he crashed in a mud hole which was next to a bees' nest in the ground. He was allergic, got stung twice and we were deep in the forest, so we had to get out asap. The bees were swarming around his bike and going 2up on my bike was near impossible. I turned my 2-stroke bike around and pointed the exhaust at the bees and revved the engine. The resulting cloud of oil/gas mix subdued the bees. My friend took the throttle, I wrestled his bike out of the mud and we made it out of the forest as fast as we could.

Noether• 17 years ago

Nowhere near as awesome as most of these, but I made a magnetic screw-picker-upper out of a broken pair of earbuds and a bottle cap.

chaosprophet• 17 years ago

Gunpowder on an omelet makes a huge difference to the taste, making it super spicy. (Gunpowder is a mix of red chilly powder, salt and a number of other spices, and is found in many Indian recipes).

saurabh• 17 years ago

When i was a kid I stuck a crumbled reflective tape to the ceiling to bounce off the remote signals to our TV. I could then just press the buttons without giving a damn where it pointed.

xenoterracide• 17 years ago

College / Certification Hack. I took A+, Network+, and Linux+ and got transfer credits for 3 linux classes, 1 networking and 1 hardware class, spending only a few hundred dollars and saving several thousand, shaving time off my time to graduate and having several certs to show for it.

Ask HN: Your biggest non-technical hack/discovery

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