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Submitted by: In a Maths class via Submit a Kludge!
Favorite Comment: Fixer mld1979 says “*blinks* I’ve learned more science here than in a physics lecture.”
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betcha that wire gets really hot. I know because I’ve done that, and placed the wire on the back of a classmate’s neck.
(come to think of it, it was a 9V. Man I was a mean middle schooler.)
It doesn’t. The only current it carries is what the calculator draws (and now at 4.5V instead of 6V). Couple of ten mA at most, and that won’t heat up a biro spring in any appreciable way.
What you did was short out a 9V battery. That will run a good number of amps through such a spring, which will definitely get it hot (and the battery itself too).
ah, science. thanks for the detailed explanation.
You did something else. If you did what was shown in the picture, nothing would get hot. If unsure, measure (or experiment, as it may be).
When the spring gets hot, its force is reduced opening the circuit and stopping than Newton Raphson calculation, just in case you forgot where is the reset hole.
Only thing is, the spring doesn’t get hot. At all.
Oh, I did not figure it, then it should be kludged to keep in place that masterpiece of microscopic notes and formulas given previosly by the teacher.
I used a 9V battery instead of 4 AA’s in my calculator… Wired it with a copper paper clip, they were pretty popular then. It newer got warm, you know. And the calculator was soviet made, so it could work without any errors or damage to the electronics even on 12V (as it finally did when I started experimenting with my Nintendo’s power supply unit).
In Soviet Russia, calculator computes you.
Soviet calculators, American calculators, all are made in China
Armageddon reference, FTW! (@ no_one)
no_one, if any engineer would allow chinese parts to be used in an electronic device in 1980s, the KGB would rip his ass of for sabotage of USSR’s defensive ability. And in 1993 we all started a new life in Russia. My calculator was purely soviet, 1988 model.
Also, concur on the IN SOVIET RUSSIA, OUTSOURCING MEANS “TO SIBERIA OR EAST EUROPE” front. Though – like modern day China – they shamelessly copied western designs like there was no tomorrow thanks to having no concept of copyright or private ownership, adding their own little touches along the way (cyrillic fonts on computers, or subtly re-engineering chips to have 2.5mm pin spacing instead of 0.1″ (2.54mm) as well as being radiation-proof … though rarely upgrading the actual power or ability lest the proletariat abuse said new capabilities), everything made to said design would be an in-house job. Got to keep industry turning, to make sure that the people have work, after all, and that the soviet “people” have “control” of their own production (and the KGB can be sure that nothing untoward sneaks in). And in a non-capitalist society, there is no concept of “lowest bidder” or “cheap imports”. Only the occasional, hush hush exporting of certain goods to get a bit of hard currency with which to buy things that the motherland can’t produce for hers—— I mean, is completely capable of making for herself! That there 3.5″ disk drive came from the Khazakstan Sony mines! And the bananas that our great leader has with his breakfast are from the carefully tended Caspian Sea banana plantation. We just liked the look of the Chiquita logo so we copied it. Mmmhmm. But you didn’t see those and you won’t tell anyone you did.
Wierd, that’s sort of the reverse of how I powered my first cellphone (tri-mode device – could be used to make calls, send texts, and club wannabe muggers into unconciousness) when it’s supplied 4.8v slab battery finally bought the farm.
4 AAs, steel drinks can tab-pull, packing tape (too cheap for duct tape, plus the back had to come off quite often as it wouldn’t recharge them (missing the “magic contact”) and often ran off part-worn alkalines from my camera)… ay caramba, eet ees workeen agen!
Thus is undervolting – personally I prefer overvolting!
Not necessarily… If this was built to run on NiCad batteries (see the Universal “No Trash” symbol?) at 1.25V each (5V total *unloaded*) and you switch to Alkaline batteries at 1.50V each (6V total) it’s a bit high – probably still within tolerances.
But if the NiCad batteries die on you during a test, and all you have is three Alkalines in your pack… Jump the one vacant cell with a pen spring, and 4.5V is close enough to run.
In fact most NiCads I’ve seen are nominally 1.2v, so that’s only 4.8v under load for a 4-set. So 3x 1.5v nom alkalines are only just out of a fairly-tight 5% tolerance.
Also if you have an actual voltmeter you know the numbers are all bullshit anyway. Alkalines start out around 1.6-1.7v no-load, and are still operable in some cases down to 1.0-1.1v … Rechargables between 1.3~1.4v and 1.1~1.2v (their volt curve is a lot flatter at the top/middle but then falls off a lot harder at the end). And if you’ve ever used a solar calculator you’ll know they can keep running on a miniscule scrap of power… even when the display is practically unreadable, it’ll work. Maybe a bit slower (4-5 seconds to do !69 instead of 1-2s) but it still works.
Yeah, overvolt the calculator so it runs quicker and finish the exam faster
I don’t know…REvolting comes to my mind.
Actually it depends on the resistance of the spring (Rs) relative to the resistance of the calculator circuitry (Rc). Assuming that the batteries are new, the voltage (Vb) would be 4.5v.
If the calculator is short circuited, then Rc becomes zero and power (V^2/(+Rs)) in the form of heat is given off by the spring because the potential across the spring is equal is higher than the potential across the calculator and the spring gives off heat. If Rc is high relative to Rs then the spring will give off very little heat.
But what is more important is the location of the duct tape used to replace the missing battery cover.
Nope. Nothing will get short-circuited. The spring isn’t connected in parallel but rather in series, just like the batteries. The path that the juice takes therefore does not depend on whether the calc or spring has more resistance since there is only one path: Through both.
If the battery connection were in parallel then the voltage would be 1.5, which it isn’t.
Based on their physical arrangement, I’m betting those batteries are in series, not parallel. This would mean the wire is not shorting the batteries, but is merely closing the circuit such that the calculator gets 4.5V instead of the expected 6V.
This means that (1) the relative resistance of the wire vs. the calculator does not matter, and (2) the wire will probably not get hot in this configuration.
It may or may not save money on batteries in the long run. As the batteries deplete, it will not take as long for them to drop below the minimum operating voltage of the calculator. OTOH, if this kludge works at all it means the calculator has a pretty wide margin for undervoltage, so may be wasting a lot of power in “normal” operation.
According to my calculator running on 3 batteries and a spring it’s actually 3 x 1.5V = 3.0V.
In what universe is 3 x 1.5 = 3?
1.5v * 3 is not 3v dude.
In a universe where the calculator doesn’t have all it’s batteries.
Ha, I get it
See what I did there?
I think this may be a subtle troll, but still…
3x”1.5v” batteries “and a spring” = (3x(1.2~1.6)) + (1x(0)) = 3.6~4.8v … not 3.0
If we’re to take it that it’s three batteries and a spring, instead of four batteries and no spring.
However if you had one of the crazy messed up early 80s casios such as my mother did for work (and a blue manual remington typewriter on which to prepare the worksheets she’d mimeograph for the class
, maybe it was 2 batteries and a spring instead of a rather inconvenient 3 batteries, no spring?
(Pretty sure that old lump needed every last millivolt it could get its hands on though – the display NEVER seemed to be up to what we’d call full strength)
Thass somthin new, I didn’t know it would work on 4.5 druther than 6 volts.
A long time ago I had a small remote-controlled car which came with a dummy battery so you decided if you want to use (as far as I remember) 2 or 3 cells.
I had one of those too! But when you ran it with the dummy battery (a black plastic battery shaped thing with a conductive pole running down the middle), it didn’t go as fast…Not as fun. Sooo i would emagine that a calculator with a “dummy” battery would make doing math less fun………..but luckily math is soooooooooooooooo fun to begin with, it can afford to lose som of its “wow factor”…
as long as you get the polarity of the spring correct, no damage will occur.
Good show, HUSABOB, I laughed.
I am using little tinfoil balls to make AAAs work in my carbon monoxide detector instead of AA. So far so good
*cough* *cough*
AHHHHHHHH hahahaha!!!!
(gasp gasp) *turns blue*
This is why fixers don’t visit other fixers homes!
oh, no worries. I am too cheap to buy any heating oil so it was really just to stop the beeping. I could take the batteries out but that wouldn’t really be a kludge, would it? Much better to use the excess AAA batteries I had on hand and some greasy tinfoil from the recycle bin.
Why would it be beeping unless the voltage is too low for it to properly work? That is, unless by saying you didn’t buy heating oil, you’re inferring that you keep a campfire in the living room going. That would explain the CO detector beeping constantly.
beeps when battery low, once a minute or so, and in accordance with murphy’s law this always happens at 3am. So I left it on the kitchen table with batteries out for 2 weeks. Didn’t fix itself. Wrong batteries did the trick. Wife none the wiser. It’s a holdover from a previous home where we had a woodstove.
QFT
The same as the smoke alarm battery running out in midsummer when the only things likely to cause a fire in the house (BBQ etc) happen outdoors in the daytime, and the light nights make it hard enough to get some precious sleep anyway.
so… 2am… in a shorter, quieter variant of a tone presumably chosen as one that we’re particularly attuned to in the realms of “WAKE THE HELL UP YOUR HOUSE IS AFLAME”… when you need to be up early for some reason, too… and you’ve leant the stepladders to your neighbour:
… mip…
… meep ….
……………..mmmeeeep…..
……….mmeep……
ohfergawdsakewhere’diputthatdamnspare9v…..
ok… i’ll “borrow” the time/alarm backup one out of the bedside clock (cmOOOON powercut!) – assuming it has one, still, and the meeping battery isn’t itself a transplant.
… and drag a chair out of the dining room…
Or you could duct tape together as many AAs as you can find (upto a maximum of 6) with a bit of tinfoil and jam it in, hoping it doesn’t itself cause a fire until the ungodly hour you’re getting up (so long as a brownout doesn’t kill the alarm) and you can yank it back out.
No, it happens never early on a nothing-in-particular evening in mid december, when the house is full of grid-powered christmas lights, lit gas fires and meals cooking on the hob, and you’ve laid in batteries “just in case” for the festive season, and the step ladders are already out.
Did you ever see those “battery adapters”? Shaped like C and D cells, you could insert a AA battery in one.
He/she Just saved the planet!
Does this mean I can just put 4 springs in it and skip the batteries?
Why, yes. Yes, of course.
Love it !
He got AA on his math exam!
No, he got AAA from missing battery.
*blinks* I’ve learned more science here than in a physics lecture.
Yeah, me too.
What a revolting kludge.
I think that would be devolting.
Spring has sprung. You do the math.
Years ago before I could afford an iPod (and I still can’t afford one), I had this little, cheap-ass MP3 player that ran on a single AAA battery. At the time, I was a delivery driver & the AAA gave out one day out in the sticks. The only batteries I had on hand was a couple of AA’s. I yanked some baling wire of the bed of my truck, some duct tape & made that little bastard work. It looked rather scary but hey, it worked.
Bravo! To paraphrase Herodotus, “Neither snow, nor rain, nor heat, nor AAA batteries stays these courageous couriers from the swift completion of their appointed rounds.”
Thank you O Great Dono1. I feel blessed.
This has been the most educational kluge yet and i thought they were just entaining
Eat Up Martha.
What do you mean the batteries are dead? Must be time to “spring” for some new ones!
Math like this, HP calculator does. Translate like Yoda, you must. Reverse-Polish notation, engineers love!
Like it, I do.
Oh man.
Back when I was in college, I did remedial teaching for secondary schoolers; mostly math, physics and chemistry stuff. One day, one Thoroughly Obnoxious Twat had to do some (even for his level) simple, straightforward, long divisions. But he had forgotten his calculator, or the batteries were flat or something. So he asked if I had one he could use. Suuuuure, I sez, handing him my HP 29C. Which is RPN. *punch*, *punch*, *scribble, *scribble*, *punch* he goes. Then, after some minutes, “Hey, where’s the equals sign?” (so you noticed that just now, eh?). “It hasn’t got one. So, you just wrote down what came up on the display. Do you think that what you wrote down is even close to correct?”. Then he has the gall to ask me for a *normal* calculator. Look, it’s working just fine, I’m here to help you explain the stuff that wasn’t clear to you in class, but I’m not your personal calculator-dispenser. If you think you need a calculator to do some long divisions, you bring a working one yourself. So: “I have a slide rule. Want to use that? Oh, and you’re not leaving before I sign off your work as finished.” (actually, he left just a few minutes later by means of my foot, to report to what was essentially the headmaster there, for repeated failure to follow my instructions and causing disturbance).
Best thing came quite a few years later; I was working spare time at a library, and he comes up to the counter (clearly unaware that I was the same guy he had the calculator clash with), with the stuff he wanted to borrow and what he apparently thought was the correct amount already laid out on the top item. Only, it wasn’t. “Ah, you still fail basic arithmetic”.
You, sir, are boring.
cool story bro
So instead of helping him learn long division, you were a dick. It’s clearly his fault he had terrible teachers like you instead of the decent teachers who taught you.
@guillaume:
and who are you, exactly?
It was boring because you basically wrote “someone didn’t know how to use a calculator. I punished them for it. i then saw this person later on in life and they added something up incorrectly. i mistakenly attributed it to the problem involved in the previous encounter and insulted him incorrectly” – ranting about something you caused without a punchline terribly interesting, is it? Especially when you were wrong… I dunno though, perhaps my sense of intrigue is skewed.
He knew long division, he just chose (out of laziness) not do do so, but nag me for a NORMAL calculator (hey, if he can’t handle RPN, that’s not my problem) which he should have brought himself if he felt he couldn’t do without.
And yes, I can be an utter asshole bastard. Especially when it comes to out-asshole-bastarding people who go assholey on me. If you choose that route, the gloves are well and truly off.
You sound a little out of place to be teaching anyone, let alone a *remedial* class, in which the students have been placed because they need extra help. God forbid someone in high school forgets a calculator, has the battery go dead, or just wants to use a regular one instead of your masochistic version. You sure showed him!
@Deanne:
“let alone a *remedial* class, in which the students have been placed because they need extra help”
Not all of them were. Obnoxious Twat was shoved off to remedial classes because his parents would gladly pay to have him bother someone else, not them, during him doing his homework. And there’s the saying about equine quadrupeds and the ingestion of water: this twerp couldn’t be bothered with getting taught, and was generally making it difficult for me teaching those who wanted (and actually needed) to.
And once more, he COULD do long division, he just chose to be obstinate, and apparently thought that by complaining about not having a suitable calculator (the use of which was only recently allowed in class, back then, and TOTALLY optional) he could get to skip that assignment. Well, he miscalculated.
Nice move ‘McGyver’, but this is the English test, not Math.
Too bad its “MacGyver.” With an a. This is pretty sweet though.
It’s obvious.. it’s supposed to take AA batteries, but buddy didn’t have any, so he put the smaller AAA batteries, and they are smaller so the last spot ends up empty. So he put a spring to make it work.
No heating.
That would only be correct if the batteries were end-to-end.
Hey, whatever works. My dad used to try and “jump” the batteries in his ancient TV remote control (they stopped making the remote controls AND the batteries that went in them) and this reminded me of that.
I’ve actually done this before when re-purposing a battery pack to use on something else.
works fine, as someone else said it just produces 4.5v instead of 6.
Once as a teenager I found myself without any batteries for my Walkman that ran on 2 AA cells. I got a length of wooden dowel and my dad’s hacksaw and cut two pieces of wood that were pretty close to the length and diameter of an AA battery, then took a universal power adapter, set it for 3VDC, and attached wires from the poles on it to the ends of my “batteries”. Worked fine till I got new AAs.
An entirely new interpretation of the Tesla’s Coil concept.
Does this mean the calculations are 4.5/6 percent correct?
Let me do the math. I’ll just get my calc… uh…I mean a pencil.
I remember from about 1982 when Radio Shack made hand-held CB radios, which (like most CBs) were rated at 12 volts. They could be powered by either 10 nicad batteries or 8 alkalines, and came with two dummy cells to fill up the space.
no wonder he is using a bic, he had to cannibalize his Montblanc!!
I tried this kludge on my abacus but it didn’t add up.
Check to make sure the poles on your abacus spring are not reversed
When the wire gets hot it’s resistance increases so less curent passes thru it so it gets colder
Science sucks!
Only when you equalize a system containing a vacuum and a pressurized volume. ….. Like a car piston/fuel-air mixture.
Science …. it sucks every day of the week.
This wouldn’t work. Every battery powered device requires X amount of voltage. This particular device obviously requires 6 volts of juice to run. Even if you short the top battery, the device wouldn’t have enough voltage to power on. Unless there is something I don’t see…like a watch battery or something.
There’s something that you don’t see, indeed. There are tiny generators on the ends of the spring, supplying the missing 1.5V. Note that you have to wind the spring between calculations.
And in the real world, battery-powered gear is designed to run on voltages that can diverge significantly from the rated voltage. Just think of the voltage difference between a primary cell (1.5V) and a NiMH rechargeable (1.2V). That’s 20% lower, but people expect things to still work. With more complex gear, like this calculator, you’ll often find a circuit to convert the battery juice to the voltage the logic circuits are designed to run at. With such a converter designed to run off nominally 6V, it wouldn’t surprise me if it kept the calculator working down to 3V.
meow
This is a false economy, it may work on a lower voltage BUT as the voltage goes down the current drain goes up, therefore the other batteries (which from the photo are clearly not re-chargeable) will run out much more quickly!
“as the voltage goes down the current drain goes up, therefore the other batteries (which from the photo are clearly not re-chargeable) will run out much more quickly!” – that’s not the case, in general.
You are assuming that the device is using a switching step-down voltage converter. It may, or it may not. Since the current required to run calculators is generally low, they could be using a plain old linear regulator — perhaps an LDO. Certainly it won’t get too hot, and it surely costs way less than a switcher.
The logic circuitry itself will have a current consumption that depends on what it’s doing, not much on what the voltage is. The reason is that all the current goes into gates that switch, and those are just fixed capacitances that get reloaded. That’s the case with CMOS logic, and that’s a given with any low-power calculating device. The gates of transistors in the logic circuit move a charge that is *inversely* proportional to the voltage. Thus the current will stay the same no matter what the voltage is. Many CMOS logic chips will work just fine at 50% of the rated voltage, if you don’t run them too close to their rated speed.
So, there’s no way to generalize like foyherald did. You have to measure first.
Yes it was a generalisation, but what calculator doesn’t show a constant LCD display (or LED for those that remember?) even if it is just 0? and as in the case of computers even if you aren’t doing anything the processor is scanning for input even in sleep/hibernate mode thus using power!
@foyherald: “but what calculator doesn’t show a constant LCD display (or LED for those that remember?) even if it is just 0?”
Well, calculators that have a Real Power Switch, like my HP29C. I doubt you’ll find any calculator with LED or VFD displays with only a soft-off; that came about with LCD displays and the associated ultra-low-power CMOS logic. And while it’s true that soft-off calculators are always on (they usually DO switch off their displays, though), it’s only a tiny part of their circuit that’s waiting (NOT scanning) for an interrupt from pressing the “ON” key.
Chuck Norris doesnt need batteries.
In college, I had my batteries fail right before a few final exams. I just stole the batteries from the projector remotes in a couple class rooms.
A remote for a projector? You were lucky. Try that when all there is is blackboard and chalk.
The tags are incorrect on this image as the comments tend to point out via context. This is not a television remote but is actually a graphing calculator.
while this MAY work I suspect it would certainly underpower the device in which case it may effect the operation of the unit AKA accuracy of the solutions punched in to the device.
Murph
Wonder what he/she did for the memory backup battery!
Dude the batteries died don’t try to spring em back to life…
I have that calculator. It’s an HP 50g, ie fairly expensive. I got mine for $136 IIRC, and that was the cheapest I could find it. I would never try that on mine for fear of breaking the calculator, though I have done stuff like this with cheaper electronics.
If you do that and the calculator “breaks”, you have every right of going to the engineer at the HP that was responsible for the design and demand a personal refund. Although HP is, these days, nothing more than a glorified PC/networking equipment manufacturer, I doubt that their engineering is *that* bad. I bet the worst that would happen is the calculator would not turn on until you’d replace the wire/spring/nail with a battery. There’s no black magic to it, unless you just don’t understand much of it. In such case, as some friendly EE to explain it to ya.
HP stopped engineering when they spun off Agilent. THAT’s the real HP, actually; I don’t know why the current bearer of that name is admonishing itself “HP, invent”, because all they can do is sell gear that consumes ink, stuff that drives the gear that consumes ink, and most importantly, ink, Mindbogglingly expensive ink.
1/1 [ENTER]
…..
3/4
Bahahahahahaha that was during an exam… while changing batteries, I somehow lost one of them… thankfully I had a spring – and no, it does NOT get hot… it worked like that for weeks, until I remembered to get a new battery =D
PS: its a HP39GS for those of you who give a crap…
the spring gets hot, its force is reduced