EEVblog

[@electronicsNmore]

I did the same thing using one of those inexpensive tally counters. Worked great with the magnet and reed switch.

[@zer0b0t]

Hacking anything, that's the kind of content I really like to see.

[@zer0b0t]

Ugh?

[@thelavian4481]

You often tell random people what to do?

[@arcade_signal]

I think he meant hacking in the original technical sense and not in the "soft" sense where the word has been co-opted by morons and applied to silly stuff. It's even been bitten by marketing people, search for "growth hacking" to discover a new and exciting world of idiots

[@anotherdayisforever]

One of my favorite DIY vids youve ever done!

[@Feedback_Jack]

Dave is SO prepared to demolish the Batterizeroo. Got all the toys lined up, I love it. I don't care about the actual device itself. But all this stuff showing how to accurately disprove the b.s. is really interesting.

[@rogerkerr5745]

I saw this done by a couple of guys who wanted to count the number of turns when winding a motor. It was a brilliant simple hack which performed perfectly.

[@PiratCarribean]

I read "Hacking A Calculator Into A Calculator" 😂

[@TechsScience]

This videos deserves millions of views

[@BendeVette]

I used this when I was 18 (34 years ago) on my bicycle to count the distance of my trip. You could enter the circumference of the wheel and each rotation would add this to the previous result. Worked wonderfull. Magnet and a reed relay.

[@nickhill9445]

Love the idea. Another possibility is to put the reed switch inside the calculator case. It can read the train directly without affecting the calculator appearance, and you can use a solenoid placed near the calculator for other applications.

[@samgab]

PS, you can also hack a cheap pedometer to do the same thing as this. They just have a little weight and switch inside which increases the count by one ever time the weight moves and closes the contact. You just remove the weight and solder wires to the two contacts and then you can connect those wires to any switch, such as a reed switch and magnet or a light sensitive switch, etc.

[@mattshilling]

Samgab Better solution!!

[@rpc72]

Samgab was gonna post the same comment when i saw yours.

[@DoRC]

batterizer test setup!!

[@linengmiao]

More of such hacking video's please! It is a real pleasure to see you hacking/modifying and reverse engineering stuff (in stead of mostly just analyzing and explaining like we are used to).

[@kryskarr23]

Cool tutorial. Big fan. Take care and keep up the quality work.

[@MyBigThing2010]

this is genius....I would never thought to do this on my own...I'm not that "creative" ...thanks for the idea, just saved me an eBay purchase, saved money and a month of time waiting for CE garbage to get here...all for the cost of a jst, a scrap of wire, solder dots and a few minutes of time! definitely gonna give this a go! THANKS AGAIN.

[@thevoid7480]

Forshadowing the batterizer test setup. ;) But why not use an arduino for that? You can collect and store the data and send it to a PC. Then you could also implement a timer that measures how much the train slows down instead of just counting loops. Collect more data!

[@travis4798]

I use to mod electronics in the past. Best wire to use for pads is computer ribbon cable and if you go online to say Amazon they have ribbon cable by 20-50 foot rolls. Solder on with low heat, tack down in a few spots using hot glue, it will never come off.

[@NicholasAarons]

That Was Awesome Dave. Keep up the great work. Nick.

[@Blendedasian]

holey queen spikes, look at this fabulous smooth footage! Thanks, dave, you're making your videos way more pleasant to watch with 50fps. welcome to the pc master race club.

[@TechGuyCharlie]

Hi Dave, such a cool project there! Would have looked great with a VFD display calculator.

[@Zadster]

Doesn't the calculator have an auto timeout? Unless you are watching it all the time, the little train will eventually stop, the key presses will cease and a few minutes later it will time out, losing the count number? The M+ button might have been a better option, as the contents will be retained.

[@EEVblog]

Good point. No issue for me as I'll be recording on video.

[@therealjammit]

I'm sure you could either buy enough cheap calculators until you find one that doesn't time out, or buy an old LED calculator on eBay. Pretty much any old LED calculator didn't have enough horsepower to do fancy things like power management. Might have to make an Ac adapter to replace the batteries.

[@akuunreach]

Nice Zadster, I was going to comment on the M+ being a better way as it keeps a perfect count vs the +1 Though Dave could just start with -1 so that the running total comes out correctly.

[@suplerb]

Zadster Whatt does M+ do?

[@akuunreach]

Mancobbler, it adds to what is stored in the memory. MS is memory store, M+ and M- add and subtract from the stored value, and MC clears the memory. So say you want to figure your pay but part of it is over time, so you take your hourly and multiply it by 40, and store it in memory. Then you would take your pay and multiply by 1.5 or w/e and then the hours of OT, and press M+ Now when you press MR (memory recall) it will show your pay for the week before taxes and withholdings. If you already knew some or most of this, I was simply trying to be thorough, plus others might read this post.

[@orvillejones1258]

Nice project Dave, thanks for sharing!

[@ExStaticBass]

This is definitely something I wouldn't have considered doing before watching this video. They say the simplest ideas are the best and this one is brilliant. I think I would put the connector in farther so the pins wouldn't stick out the side but that's the only thing I'd change. I loved the Keysight O-scope hack too which I just finished watching before this one.

[@tomwimmenhove4652]

I remember doing a project like this when I was around 6 or so. I connected one wire to our (aluminium) sink, and the other in a glass of water. By placing the glass below the tap and having it drip into the glass, the calculator would count the number of drops that have fallen. At the time I didn't appreciate the incredibly small change of current by the charge carried by a single drop. I'm still amazed that it worked at all :)

[@RPBCACUEAIIBH]

If you press "+" then "1" instead of "1" then "+", then it starts from 0 not from 1 works the same way. You can also type in an initial number, from which to start counting, then "-" and "1" to count down, you can also use another numeric constant instead of "1" to count by that numeric constant.

[@mbirth]

I somehow expected you to seamlessly implant a calculator into a counter top …

[@tambechristian]

You are a genius Dave !!

[@SlyPearTree]

I used that trick to make a cheap digital voltmeter in the 80's. If I remember it counted how many fractions of second acapacitor needed to charge from 0 to the same level as the voltage being measured (or discharge from measured voltage to 0). The fractions of second were probably relatively large since the calculator could not respond that fast, that was probably due to internal debouncing of the keyboard circuit. I think I took the idea in a magazine. The result was not really seriously usable but made a nice little experiment to learn a bit more about electronic.

[@andrewsalton7670]

simple,cheap and reliable. nice one.

[@umajunkcollector]

happy new year dave, good one Don

[@JONOVID]

IMO I would use hot glue to anchor wires in place. also I would use sockets as the wires end connectors so you can close the back up on the calculator and re-use for other counter type jobs in the lab.

[@waynerussell6401]

I had a client who wanted to detect how often a reference book was used. I embedded a watch module in the spine with reed switch and magnet and mode to set minutes. Only counted to 60 but that was adequate.

[@hisab-n8c]

Nice battery tester ! Happy new year!

[@horiamorariu]

Genious! Just remainds me that in a very old TEHNIUM (Electronics Magazine), back in 1980, in Romania, there is an article of WINDING MACHINE COUNTER - exactly the same, but based on Texas Instruments TI30. Nothing new under the sun. But maybe for some young hobbysts is new. Cheers Dave!

[@bornfe5127]

wow now ive got a counter for inductor and transformer projects thanks dave ("beauty')

[@aserta]

I used one of those electronic finger counters. Works perfectly well for those who don't want to do complex things.

[@mooncabbagere]

This week on EEVBlog's The Dave Jones Show, Dave hacks a calculator to count automatically!

Great post Dave!

[@billboe9784]

Great video! Ive never seen a hardware calculator hack before.

[@88njtrigg88]

Can be used also for a home made anemometer project, with the addition of a stop watch.

[@tasteless_5915]

If you get a knife down the middle of the plastic heat rivets you can “drill” them out as it separates the outer ring from it and you can’t take the chip out.

[@brainndamage]

I've used this method before for counting turns on a coil winding machine, the problem is that the calculator can only count so fast until it starts missing pulses. But for slow counts it is ideal.

[@fdjhrfgjry]

Hey Dave, another great feature of this ghetto-counter is that you can determine the +1 amount so flexible, eg. if used in composed counting formulas and tailor them (other than 1;) to match your purpose or eg. 6 decimal position or better precision. Almost literally a streetwise universal counter ;)

[@techalyzer]

I have done this on my bike ages ago, only instead of 1, I used to put in the tire's circumference to measure the distance.

[@antonnym214]

Very nice! We can get these calculators at the Dollar Tree (everything's a dollar), so this is an awesome use for one.

[@krzysztofsoja5301]

Back in a days I used this method to make distance couter for my bike :)

[@SimonE-fz5pc]

Funny found a box recently in the attic where my father did the same thing to count ants in a tube leading to food with a light switch for his Dr (PhD) thesis back in 1974! Sure it was an old "4 banger", as Dave says, but it still worked and high tech back in the days.

[@tzisorey]

I had a calculator as a kid, that had a little thumb-trigger "Count" button - so you could take tally of things easilly. Had one of those old light displays on it too - doubt it was LED, but some sort of low-power red 7-segment things.

[@didierdubos]

Hi, In order not to have to substract one to the result, just substract 1 to 0 then add 1 and press twice + key. You then start from 0 cheers

[@MrJohn1966elliott]

In 1984, I build it, use for "Odometer" fit my push bike. I put magnet on spokes bike wheel.

[@magista247]

I did exactly the same 35 years ago with a Sharp calculator on my bicycle to measure the precise length to the basic school ;) So i was the first to have a 'bike computer'...

[@frogz]

heres a little hack for you, 301 green laser pointers(or any other cheap 18650 green laser pointer) aimed behind the board lets you see right through most circuit boards to see the traces

[@UAUnstableMaker]

Oh, i did this thing as a child in early 90's, but it was used to work as an odometer for my bicycle. I just had to add a length of the wheel

[@welshgoldferret5107]

Awesome, I remember doing this when I was making Tesla coils on my homemade winding machine, worked well.

[@dheujsnrhfydhehehshshhdggsd]

really enjoyed a simple kid friendly project

[@abymohanan2043]

Thank you so much for this video 👍🏻👌🏻✌🏻

[@MisterTalkingMachine]

We used to do calculator adding races in school this way.

[@ravivashatkar5585]

I had the same idea Dave .... I never tried it .. thankyou for doing this 😊😊😊👍

[@danielpare9129]

You could also start the claculator with the value (-1) + 1. Then it will be set to Zero and no need to substract 1 at the end.

[@Zamsky39]

I really like videos like this one.

[@giga-chicken]

I actually wrote a python script for a raspberry pi to do this, but it does more than count, it also records the exact time of each lap so that a time line can be drawn for the entire experiment. The result is a somewhat gigantic text file which I feed into a java applet to generate a pdf.

[@SurajGrewal]

plus since it was button input to begin with, it has debounce

[@RinconingenierilEsp]

I love it, thumbs up

[@tonesoft1956]

New this when I had my first Casio calculator in the late 70s :D

[@danielmoraes9637]

Great job!

[@petermuller608]

Having a toy train: nerdy Using a calculator to manually count the laps: nerdy Hacking the calculator to count the laps of your toy train: king of the nerds xD

[@DouglasLuis-t6o]

Very good seeing in Brasil 😮

[@faybercova]

what amazing video, congrats

[@Jones12ax7]

as a kid in the 90s I used a crude switch on the front wheel of my bike and a hack like this. I type the wheel circunference, 2.1 at a time, and + so the I could measure the distance. I even placed a switch in a shoe to make a pedometer for a science fair of my schol. Good times before the microcontrolers invasion that we like so much today.

[@EgoShredder]

My uncle and I did something similar to make a digital speedometer for my bike around 1980 I think. We used little reed switches near the wheels to measure the speed etc. It worked perfectly and I was a proud kid, with lots of DIY gadgets! Good times :-)

[@nrdesign1991]

I made a bike pedometer that uses the AC voltage coming from the hub-mounted generator as a signal. It can't charge its battery through that yet though. I don't have any plans on working on it at the moment.

[@maicod]

as a kid I had a Fleischmann train and used 2 metal strips that when the train ran over it were pressed down and so the circuit closed and I let a railroad-switch flip over

[@tin2001]

I did the bike distance counter thing when I was a kid too. I wonder if I still have that calculator somewhere....

[@kaziq]

I once taped a switch (just two flat metal plates) to my heel, and wired it through the sleeve to an old bike counter stripped to my wrist. Then set an average step distance as the wheel circumference in the counter, and had a crude distance counter. And it was painful too after some time with the swith on my heel.

[@SpikesMavic]

Fantastic, just what I need, am wanting to count the amount of turns of wire for a transformer

[@mirkomueller3412]

Nice Idea - might come in handy someday.

[@MisterBadNews]

This is how we used cheap calculators back in '90 to count the number of coils on homemade coil winding machine. Using a calculator, a magnet and a reed switch attached to =.

[@TheBendixSA]

Dave if you do some simple math and start the calc in constant mode with the right amount added, then that becomes a distance counter without ANY modifications. COME ON GIVE IT A BURL!!!

[@FennecTECH]

I would use lego and an solenoid to simply push the button each time lol

[@RyanUptonInnovator]

you forgot duct tape.

[@FennecTECH]

dont need duct tape when you use a lego flatboard as a base

[@RyanUptonInnovator]

I will attack your lego flatboard base with my duct tape x-wing fighters. Prepare your exhaust valve for my proton torpedos.

[@FennecTECH]

that sounds painful

[@RyanUptonInnovator]

At first it is like ow ow ow, but then it is oh oh oh. The worst bit is the child support.

[@billl605]

Go green, power the loco with a solar cell, great video, and a thumbs up.

[@brianhoskins1979]

Nice. As a point of interest, I would have liked to test it on a signal generator just to see what the maximum counting speed is. Not that it matters for your application, just a case of "well, I've built it... but for fun let's see how fast it can go".

[@johnrickard8512]

A TI-83+ series calculator(NOT the 84+CE) can be hacked in a similar way using its link port(actually, it could be made into a dual counter)(I should also mention that TI was aware of this when they made the CBL2 equipment interface, which can also do this).

[@genericgreensquid6669]

This was helpful!

[@ryangriggs5767]

Very nifty idea! I wonder what the maximum input frequency is? (probably some multiple of the key matrix scan rate?)

[@tehaxor69]

You could of used a TI 83/84 with a arduino as a remote. These calculators already have a built in ROM Call for remote button presses via the link port. You could write a TI Basic program that scans the getKey var for a increment and reset button press.

[@KrazyContraptions]

I'm gonna make this but connect a binary counter circuit to it instead of the calculator. It will be fun!

[@vehasmaa]

i knew about constant mode but newer tought one could hack calculator to do it like that... Sure gives new usefulness to bargain bins 4-function calculators...

[@gorillaau]

Nice that the troll doll came along as a witness.

[@Aleziss]

speaking of carbon contact, what is the best way to fix rubber buttons that have their carbon contact not working anymore beside replacing the buttons ?

[@techalyzer]

I succesfully used tiny aluminium foil pads you can just cut with a hole puncher or scissors superglued to the carbon contacts on the rubber.

[@Yrouel86]

They might need just some cleaning with IPA (both button and contact) or a very light sanding (just pass the button a couple of time on some paper and then try it)

[@Aleziss]

+Ri Max ok, is that type of repair holding good for a long period ? it's for a remote control that is used everyday and button presses multiple time a day

[@Yrouel86]

If the problem is dirty contact it will last long enough I think (more or less as much time it took to get to where it is now).

[@techalyzer]

I haven't used it like that but I guess it should hold.

[@jschroedl983]

OMG I loved those thomas the tank engine tracks

[@KevinOsborne1987]

Joe Schroedl AKA 'Brio'

[@Eicles]

Annoying that there always has to be some dislikes; this is bloody brilliant! I'll have to remember this one, might come in handy! :-)

[@Alex-je6od]

a glob of coil coating epoxy on those kind of bodge wire solder joints works wonders. (as long as you don't plan on changing it)

[@adkharu]

You only have to enter "(0) + 1" and it'll prevent you having to subtract 1 from the total.

[@shawn_2]

Super cool!

[@Crazytesseract]

What's the difference in cost, if you use 4 bit 74XXX counter ICs in cascade, a bcd-to-7 segment convertor IC, and a few 7 segment displays, and wires, plus a bread board? And how do we latch the digits using multiplexing?

[@EscapeMCP]

Once you have hit 1++, then hit equals (which will give you 2 on the display). Then enter ANY number (e.g. 0) and the next press of the equals key will increment this new number by one. This way you don't have to do that incredibly difficult "subtract 1" maths from the final result. You can use this to start a count from ANY number, e.g. -5 will give you 5 'test' laps before the count starts. Or perhaps try 55378007 and see what happens on the next lap?

[@Zauviir]

Is the batteriser fail train about to leave the station?

[@Andrew_Sparrow]

ive used the cheap dollar store step counters in a similar way, even easier to hack :)

A tiny drop of hot-snot also works perfectly for securing those wires.

[@kaizen9451]

Good call.

[@BlankBrain]

03:29 should'a used your Crocodile Dundee knife!

[@RashidKazawe]

Thanks🎉

[@Coolkeys2009]

Hope there's no auto power off on that calculator :-)

[@EscapeMCP]

Only a worry if train takes longer to lap the circuit than the auto-power off time (maybe due to a crash, leaves on the line or strike action from the minature train drivers union). Otherwise it would keep resetting the power-off timer each time around and keep the thing on.

[@Eletronicafg]

The problem is that you need to be watching the test until the battery of the train drains out. Otherwise you'll lose the the count.

[@jagardina]

Or keep a camera rolling.

[@bornfe5127]

i thought auto power off has something to do with inactivity

[@Coolkeys2009]

Inactivity occurs when the battery under test runs out, Dave has taken care of this buy videoing it as others have said.

[@Luclips123]

Thanks

[@danweecc]

This looks like you're about to do an AA battery performance test - with all those batteries in the background and this test-rig. Is that going to come out in a video soon?

[@berenscott8999]

I actually thought you'd go a little bit more hacked then just this :P

[@scarrypolpetta9006]

Beren Scott why bother He wanted to build a counter and he did, the easiest and fastest way, showing off how anyone could do it without any complex circuit, without an electronic engineer degree and on pretty much every calculator, without choosing one from the 80' that would have had a different circuit, with easy to mod wires I don't see the point of making it harder

[@blenderbuch]

In the time as the four banger got cheaper we used this to make km counters for our bikes, enter the circumfence of your tires key in + + + + + + Or was it M+? I cant try only UNP Calcs here now