Author Topic: EEVblog #962 - Hacking A Calculator Into A Counter  (Read 6581 times)

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Online EEVblog

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EEVblog #962 - Hacking A Calculator Into A Counter
« on: December 28, 2016, 01:44:22 pm »
How to hack a calculator into a test system event counter.



 
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Online Mr.B

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #1 on: December 28, 2016, 01:52:08 pm »
My, my... You have been busy today Dave.
Thanks for that video. Nice simple hack to achieve the desired result.
Time is the overseer of all things.
 
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Offline Muttley Snickers

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #2 on: December 28, 2016, 02:02:29 pm »
Nice enhancement.   :-+

Unattended monitoring could be a trap for young conductors should the APO kick in.   :-BROKE

One smart cookie, better make that two for good measure.
 

Offline rrinker

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #3 on: December 28, 2016, 02:42:57 pm »
 I remember doing that as a kid, adding an external contact to the = key. I had some big plan in mind but somewhere I lost interest and never finished. I don't THINK I got into any trouble - claculators weren't exactly a dime a dozen like they are these days, but I'm pretty sure we had 2 identical ones and I didn't touch the one that was most frequently used.

 

Offline DTJ

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #4 on: December 28, 2016, 02:59:54 pm »
This is a neat idea. I remember seeing it done in the 70's and used in conjunction with a astronomy telescope. Instead of adding '1' each time the contacts closed the fraction of a degree per rotation of the positioning lead screw was entered. Could be a useful hack for a cable reeling set up.

One place I worked at we needed a quick and dirty field amphometer. 
We hacked transistors across the start and stop buttons of a cheap stopwatch and put together a circuit similar to the Electronics Australia (or ETI?) magazine 'Coax Sensor Amphometer".


 
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Offline MK14

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #5 on: December 28, 2016, 03:05:51 pm »
I did similar, a long time ago, as a hobby project. If I remember right, I used a relay, so it could count any low frequency source that could drive the relay. You can also use a 4016/4066 cmos analogue multiplexer, may need a monostable (set to around 250 ms, else the calculator may not respond) as well. (CD4066B CMOS Quad Bilateral Switch).

In theory you could use a transistor/mosfet. But it is tricky, because (as Dave says in the video), to get that to cope with the unknown multiplexing keyboard scan scheme.
 
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Offline smithnerd

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #6 on: December 28, 2016, 04:52:24 pm »
I recently needed to map out the keyboard matrix for the Chinese scientific calculators, which are currently available from poundshops here. The plastic/carbon keyboard membrane is glued on, so soldering to the PCB is completely destructive (but they are absurdly cheap). Pads are numbered left to right.
 
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Offline jonovid

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #7 on: December 30, 2016, 08:36:37 pm »
as posted on your yt.  IMO I would use hot glue to anchor wires in place. also I would use sockets as end connectors so you can close the back up.
and re-use for other jobs in the lab.  :-+ Chinese calculators & DMMs make cool loggers & hobby projects
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Offline Luminax

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #8 on: December 30, 2016, 11:02:14 pm »
Hmmm.... I remember one of my old horizontal Casio can do a 0+1 and just press equals forever more and it'll add up. I forgot what the model is ... or if it's even really Casio or some Wun Hung Lo brand
Jack of all trade - Master of some... I hope...
 

Offline AdiGital

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #9 on: January 01, 2017, 08:15:06 am »
 ??? Hacking? A Calculator? Seriously?

Dave! Please. I love watching your channel and learning from you but this is... just shocking. I'm sorry but it really is.
 

Offline timb

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #10 on: January 01, 2017, 10:08:44 am »
??? Hacking? A Calculator? Seriously?

Dave! Please. I love watching your channel and learning from you but this is... just shocking. I'm sorry but it really is.

Really? Why?

He needed a lap counter for the Batteroo train test. This was the quickest, easiest way to do it.

Personally, I think it's super resourceful and very clever.
Any sufficiently advanced technology is indistinguishable from magic; e.g., Cheez Whiz, Hot Dogs and RF.
 

Offline amspire

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #11 on: January 01, 2017, 10:27:39 am »
??? Hacking? A Calculator? Seriously?

Dave! Please. I love watching your channel and learning from you but this is... just shocking. I'm sorry but it really is.

Really? Why?

He needed a lap counter for the Batteroo train test. This was the quickest, easiest way to do it.

Personally, I think it's super resourceful and very clever.
I agree. In terms of using something on hand that essentially has zero cost (people throw these things out), can run for hours and show up clearly on the single frame, it is a pretty brilliant solution. There is a better solution? Dave could have used his Agilent counter, but the calculator seems a better solution for the task. The counter display would not have been visible from the top down shot.
 

Online nctnico

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #12 on: January 01, 2017, 11:05:00 am »
Weirdest thing I hacked together with pushbuttons where pushbuttons attached to a cable to push buttons. That way there was some certainty that two systems where started at the same time without modifying one of the systems. Yeah, I once had a job where these kind of wacky ideas saved the day. I still kinda miss working there.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline wilfred

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #13 on: January 01, 2017, 11:18:14 am »
I agree. In terms of using something on hand that essentially has zero cost (people throw these things out), can run for hours and show up clearly on the single frame, it is a pretty brilliant solution. There is a better solution? Dave could have used his Agilent counter, but the calculator seems a better solution for the task. The counter display would not have been visible from the top down shot.
I just came back from Coles and I just chanced to notice the calculator is the model currently sold in Coles.  So might not have actually been to hand. But I do like creatively using things available to hand or bending them to an unintended purpose.

If you can be creative in little ways then you can be creative in big ways. It trains the mind to look beyond what is obvious.

 

Offline jonovid

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #14 on: January 01, 2017, 12:30:47 pm »
Quote
Quote
Quote from: timb on Today at 10:08:44 AM
Quote
Quote from: AdiGital on Today at 08:15:06 AM
??? Hacking? A Calculator? Seriously?

Dave! Please. I love watching your channel and learning from you but this is... just shocking. I'm sorry but it really is.
Really? Why?

He needed a lap counter for the Batteroo train test. This was the quickest, easiest way to do it.

Personally, I think it's super resourceful and very clever.
I agree. In terms of using something on hand that essentially has zero cost (people throw these things out), can run for hours and show up clearly on the single frame, it is a pretty brilliant solution. There is a better solution? Dave could have used his Agilent counter, but the calculator seems a better solution for the task. The counter display would not have been visible from the top down shot.
I would do the same as Dave.  :-+  but used maybe hot glue not tape.
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Offline AdiGital

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #15 on: January 01, 2017, 11:22:17 pm »
??? Hacking? A Calculator? Seriously?

Dave! Please. I love watching your channel and learning from you but this is... just shocking. I'm sorry but it really is.

Really? Why?

He needed a lap counter for the Batteroo train test. This was the quickest, easiest way to do it.

Personally, I think it's super resourceful and very clever.

I didn't want to be rude. Especially in my first post. I follow Dave's channel for a long time and I admire him and his work. I just couldn't believe he would actually invest the time and create an episode on exposing calculator's key. I'm not negating the idea and yes, this is the right and clever thing for the task. But even so, all I would expect (considering EEVBlog's high standard) was no more than a mention and seeing it in action rather than how to get the wires out.
 

Offline VK3DRB

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #16 on: January 01, 2017, 11:48:52 pm »
I remember doing this is 1983 on a cheap 4 function calculator, except I had to do "+, 1, =" because it had no constant K function. One CMOS buffer IC and different RC time constants at the inputs would produce a round robin of key presses. It worked a treat and I thought it was clever because the circuit was so simple. If anyone is interested I'll see if I can find the circuit in my old filing cabinet and publish it here.
 

Online IanB

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #17 on: January 01, 2017, 11:56:53 pm »
I didn't want to be rude. Especially in my first post. I follow Dave's channel for a long time and I admire him and his work. I just couldn't believe he would actually invest the time and create an episode on exposing calculator's key. I'm not negating the idea and yes, this is the right and clever thing for the task. But even so, all I would expect (considering EEVBlog's high standard) was no more than a mention and seeing it in action rather than how to get the wires out.

But why not? Not everyone who watches is an expert in everything electronic, and even a simple mod like that can stimulate thought about how to approach it and alternative ways of doing so.
I'm not an EE--what am I doing here?
 

Offline SeanB

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #18 on: January 02, 2017, 01:06:24 am »
Well, the calculator use has been around for a long time, at least since a calculator was available at such a low cost that you could think of them as something with a counter, display and a small controller you could buy for under $5. I remember appnotes that used them to make totaliser units, and even one using it as a postscaler for a faster counter, to improve resolution and give extra readout, at the expense of increased gate time.  Another used a sequence of RC delays, like VK3DRB describes, to enter the startup keypresses on power on ( using a calculator that had no APO functionality of course)  to make a "low cost robust totalising 8 digit counter for under $10" IIRC.

The calculator provides really good keyboard debouncing, reliable counting and in this application, a perfect solution instead of ordering a counter that likely would never be used again much. Dave already has a plethora of cheap calculators, so just grabbing one, likely from the dumpster room as well, tossed out because they did not want to dust it ( yes it happens) is both cheap, efficient and a good solution to the problem.
 

Offline jonovid

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #19 on: January 02, 2017, 03:23:09 am »
Quote
I didn't want to be rude. Especially in my first post. I follow Dave's channel for a long time and I admire him and his work. I just couldn't believe he would actually invest the time and create an episode on exposing calculator's key. I'm not negating the idea and yes, this is the right and clever thing for the task. But even so, all I would expect (considering EEVBlog's high standard) was no more than a mention and seeing it in action rather than how to get the wires out.
You cannot please everyone 
if Dave had designed and built two identical dedicated pieces of batteriser testing lab equipment from the ground up with fabricated counter pcb's and crowdfunding of the cost. then had programmed all the counter logging software with a full color clock displays showing seconds plus cycle per lap, in real time milliamps voltage  this requiring wireless data link modules if a moving toy is used in the testing. requiring a second power supply on the toy. had then setup two identical test rigs side by side. at the same time.
maybe everyone will be happy.  ::)  government departments work this way.  :-DD
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Offline wilfred

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #20 on: January 02, 2017, 11:00:45 am »
But why not? Not everyone who watches is an expert in everything electronic, and even a simple mod like that can stimulate thought about how to approach it and alternative ways of doing so.

Agreed.

The electronics Youtube/blogging sphere is already very niche. You could get an order of magnitude more views on YT unboxing toys (2 orders of magnitude even)  or by cutting stars out of a cereal box and pasting glitter to them for christmas ornaments.

It does no harm to be inclusive to newcomers to electronics. I used to read claims that amateur radio was in decline because a significant core of old-timers were disinclined to tolerate newcomers. I don't know whether amateur radio is in decline or if it is that is a reason but it was what I had heard. Of course Alan (YT:W2AEW) is an exception to prove it isn't universally true. Arduino is a case many here would be familiar with where it is undeniable that a core of experienced EE's will publically look on newcomers with disdain. It is not uncommon here to read that Arduino is not a true microcontroller or it is not "real" electronics.

Two things I am entirely confident of. The fewer the number of spokes in a bicycle wheel the more expensive the bicycle. The more confident the individual is in their own knowledge the more likely they are to be helpful to newcomers. By that I mean the less they fear being wrong or ignorant not that they are experts in the field. You can find experts who are unwilling to share knowledge.

Dave isn't amongst them. Unwilling that is.

PS: Don't take the glitter stars as a literally true example. You know what I meant. I did not research it first. Here is a literally true example of what can be popular on YT.


« Last Edit: January 02, 2017, 11:05:40 am by wilfred »
 

Offline rrinker

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #21 on: January 02, 2017, 12:13:40 pm »
 Except Clive has stated several times that he just did that as a spoof. But it does prove what level your typical Internet user operates at - since THAT one went viral and got him name recognition. And as he explains on the recent questions and answers and rants video he mentions how he engaged a company to promote it and manage ad revenue, which he regrets, as they never pay, he had to sign over full rights to the video, and they do nothing to prevent the video getting ripped off - which he doesn't care about since he doesn't get money from that one anyway. It is in every way an atypical video for his channel.

 

Offline wilfred

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #22 on: January 02, 2017, 02:21:11 pm »
That recent Q&A was how I came to find it. I hadn't bothered to watch it out of his back catalogue before yesterday. It was a good warning he was able to give to new youtubers about staying away from the marketing channels.
 

Offline jh15

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #23 on: January 02, 2017, 03:59:55 pm »
Back in '81 or so we did mileage tracking for a bicycle club newsletter for brags 30 or 80 - 100 miles a day on weekends.

A friend strapped a calculator to the rack a reed switch on the frame and a magnet on the spokes. exactly as as dave did.  Owner happened to have a Honeywell computer in his basement and calculated wheel diameter etc. to get results.
« Last Edit: January 02, 2017, 04:09:33 pm by jh15 »
tek 575 curve tracer top shape, 535 top shape, 465. 545 hickok clone, Telsa Model S,  Ohio Scientific c24P single board computer, many c-64 from my club days, Giant electric bicycle, Rigol stuff, Heathkit AR-15 receivers 2, Heathkit et 3400a trainer and interface,
 

Offline rrinker

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Re: EEVblog #962 - Hacking A Calculator Into A Counter
« Reply #24 on: January 02, 2017, 04:12:37 pm »
 I remember building a (I'm pretty sure it was Radio Shack) bike speedometer that was pretty much exactly that - a magnet on the spokes and a reed switch. It used an analog meter movement, so I'm guessing it just displayed the average mv from a simple capacitor circuit where the cycle was started/stopped by the reed switch.

 As to Clive - I'm a rather obsessive person when I get my teeth in to an interesting topic. A bit over a year ago when I first found this forum, I watched a few of Dave's then-current videos, then I went back and started all the way back at the beginning and pretty much watched every single one in order. Pretty much the same with Clive although I did get bored with the multiple of the same sort of thing so I've skipped quite a few. That series he did with stuff from his day job was quite interesting to me.

 


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