Yet another HP35S question



#25

I almost hate to ask this question seeing as how the poor HP35S has already been autopsied even before birth, but does anyone know if it has a clock/stopwatch? I found this to be the greatest help in my day job, and would dearly love for it to be included.

I also suspect that the 35S picture that has been released is different that what we will see in the end. As a result, I am not sure that spending a lot of time re-designing different functions is an exercise of anything more than fancy. I mean, HP would be giving the competition a lot of information if they released this calculator's sales material first and the calculator six months later. Even the pictures of it with the baby (cute baby, BTW) don't clearly show the keys.

Just a thought.


#26

I do not believe the 35s will have many more capabilities than the 33s (maybe more storage registers and if they are nice more program labels). There is debate about matrix ability. I doubt very much there will be a stop watch. I am not aware of too many calculators with stop watches (of course the old 55 and 45 many moons ago) and the 33s does not have that capability.

Edited: 7 June 2007, 2:22 p.m.


#27

Possibly you could write a program that performs an operation and loops until you break it.

Then, calibrate how long it takes for each loop by averaging over a measurable time interval using a regular stopwatch. Have it track the number of iterations (a counter), and simply multiply the counter by a time conversion constant as the final operation?

Just an idea for a workaround.

ECL


#28

...or you could get a digital stopwatch for a few bucks and use that instead. A good one is pretty cheap nowadays. I bought one at a sporting goods store for about $15 over 10 years ago and it still works great. We got one in a McDonalds Happy Meal a few weeks ago for free and it has all the same features of the 10 year old stopwatch. (...and has a magnifying lens on the front to make it easier to read.)

I also use a Sunbeam kitchen timer that I got for $4 from Walmart a couple of months ago. It measures in seconds, counts up, or counts down (in minutes only, up to 20 hours) It also gives count-down beeps at 10 and 5 minutes before sounding the alarm at 0. Depending on how fine your measurement needs are, it could work.

Besides, will the calc will let you use it for it's intended purpose while the clock is running?

#29

The 48g family has clocks and stopwatch
The 17bii, 27s, 41c has a clock
even one of the classics or woodstocks had a clock--and I think you could hack a clock function in the 45?


#30

Quote:
I think you could hack a clock function in the 45?

Please find the answer in this very museum :-)
#31

The HP-55 had a quartz crystal controlled stopwatch. That and the better statistics is why I bought it over the newer HP-25 (the 25c hadn't come out yet). My dad had a 45, and the local HP rep showed him how to access the faux stopwatch with a three finger salute.

The stopwatch in HP-55 was very useful in college physics for timing experiments. Also, one time in surveying we had to find our latitude/longitude by doing sun shots with a transit. The stopwatch allowed me to synchronize with the time signal from WWV (from a shortwave radio), walk it over to the transit, and work for a long period with very accurate times to record with our angles. Our group was the only one within thirty miles of the correct location, and we were less than half a mile off (mostly in the E-W direction; our N-S was almost dead on).

Oh, it was also uesful for measuring the hang time of punts during football games I was watching instead of doing my homework.

Fred

#32

The 28C/S has an hidden clock feature. It runs in the background and doesn't interfere with calculations, as it should. May I add that I love the 28's form factor (many many keys...).

In other brands, I recall only the TI65 with a whole second resolution clock capable of running in the background.

The best clock and timing integration IMHO remains the HP41 Time Module.


#33

Quote:
The 28C/S has an hidden clock feature. It runs in the background and doesn't interfere with calculations, as it should.
Why do you think it should interfere with calculations?

haha, just kidding!

#34

Quote:
I do not believe the 35s will have many more capabilities than the 33s (maybe more storage registers and if they are nice more program labels).

Jeepers, I hope there are more labels! With all of those registers, being restricted to 26 measly labels is like being in a candy store with all of the goodies inaccessible, under lock and key, expect for a few choice morsels at a time.

Quote:
There is debate about matrix ability.

I have an abundance of optimism that the the mysterious (i) and (j) key labels may actually refer to matrix element addresses under certain conditions. Even if there is no intrinsic matrix abilities, if there are adequate registers and labels it should be feasible for a geeky sort with too much spare time to port, say, the MATRIX routine from the HP41 Math Pac module to the 35S paradigm. This could be challenging if i and j are the only indirection registers available--remember on the 41 any of the 319 registers can be used for indirect addressing. But if it worked, it should be pretty fast--cut up the 33S if you will, but there is no doubt that it is somewhat faster than the 42S and much faster than the 41 or 15C, and the 35S should inherit this speed. Of course, only the most determined sorts will want to enter the 500+ steps into the 35S, but it should be a labour of love for the truly nerdy.

For the busy and practically minded, I expect computer software will just have to do for matrix work, or the 15C, 42S, or one from the 48 or 49 series for those who have them. But I do think the 35S will prove excellent for routines that iterate over a series of computations to convergence and produce a single result, as in the computation of special functions. My 33S is loaded with routines I have written (or borrowed and adapted) for the incomplete gamma functions, which in turn can be called to compute the error functions, the cumulative normal distribution, and the chi-square distribution. They are really zippy and I look forward to transferring them to the 35S.

Les

Edited: 8 June 2007, 11:07 a.m.

#35

Quote:
I almost hate to ask this question seeing as how the poor HP35S has already been autopsied even before birth, but does anyone know if it has a clock/stopwatch? I found this to be the greatest help in my day job, and would dearly love for it to be included.

Isn't that what a watch is for?

Dave.


#36

The reason for having a clock in a programable calculator isn't so much for checking the time but is very useful to do calculations based on current time without having to enter the time and also it can be programmed to run program based on time.

#37

Hi, Jim --

Quote:
... does anyone know if (the Hp-35s will have) a clock/stopwatch?

As others have pointed out, the Pioneer-series HP-17B/BII and HP-27S, as well as the HP-48/49/50 models, have a clock. The HP-41 Time Module (built into the HP-41CX) has both a clock and stopwatch functions.

However, the Pioneers include this feature for business and financial purposes (alarms and calendar functions), the HP-41 can be a controller of peripherals, and the others are top-of-the-line RPL models. The HP-35s will not have these functions and attibutes that would justify clock and stopwatch functions.

A potential problem is the thin CR-2032 "coin" cells that the HP-35s will likely use. They don't hold much charge, and would not last if employed to drive a clock.

As for stopwatch functions on wristwatches, that's not a given. It seems that the main choices in stores are convoluted multifunction digital "sport" watches or analog dress watches that offer little except HMS and a mechanical date display. That's why I still wear a 26-year-old Seiko model with a versatile digital display (including time, alarm, day/date, and stopwatch) above an analog HMS display.

-- KS


#38

Quote:
A potential problem is the thin CR-2032 "coin" cells that the HP-35s will likely use. They don't hold much charge, and would not last if employed to drive a clock.

The watch our wrists seems to manage for a year using one such battery.
A real time clock module is not going to draw a significant current : something in the 500nA region.

Not including one is a feature/cost/product-positioning choice alone.

#39

Hello Karl,

Quote:
A potential problem is the thin CR-2032 "coin" cells that the HP-35s will likely use. They don't hold much charge, and would not last if employed to drive a clock.

I don't think so: In my small collection, I have several calculator/clock/worldtime/alarm-gadgets that run on a single CR2032 cell for years with the clock display always on!

Quote:
As for stopwatch functions on wristwatches, that's not a given. It seems that the main choices in stores are convoluted multifunction digital "sport" watches or analog dress watches that offer little except HMS and a mechanical date display.

That seems to be one of the strange differences between the US and Europe: Here, you have a very wide variety of analogue watches with stopwatch function, with prices varying from very cheap quartz watches (like some "Swatch-Chrono"s http://www.swatch.com/) to quite expensive mechanical ones (e.g. http://www.fortis-watch.com http://www.breitling.ch/en/ both brands are very popular amongst aviators).
I myself don't like to wear a watch (nor any other kind of metal stuff on my body) but still I have accumulated several such watches over the years ("as a pilot, he cetrainly needs a pilots watch...").

Greetings, Max


#40

Quote:
(nor any other kind of metal stuff on my body)

...except for a RPN calculator in your shirt pocket - will say close to your heart :-)

#41

I stated:

Quote:

A potential problem is the thin CR-2032 "coin" cells that the HP-35s will likely use. They don't hold much charge, and would not last if employed to drive a clock.

Max stated:

Quote:
I don't think so: In my small collection, I have several calculator/clock/worldtime/alarm-gadgets that run on a single CR2032 cell for years with the clock display always on!

Donald stated:

Quote:
The watch our wrists seems to manage for a year using one such battery. A real time clock module is not going to draw a significant current : something in the 500nA region.


What you both say about the current consumption seems reasonable. I, too, have a wristwatch whose single CR2032 cell lasted for a few years, even with the display always on.

However, I and others got very short life from the original twin CR2032 cells in the HP-33S, despite sparing use. I've also noted substantially shorter battery life of the three 13/44/76/357 "button" cells in my Pioneer-series models with running clocks, also used very sparingly. (I now store them in "coma" mode by turning them off with the keys in the upper and lower right-hand corners pressed.)

I haven't researched any tech specs for disposable batteries (and these are generally not given on the package), but I'd surmise that the shape of the CR2032 precludes it from storing very much energy. The cell doesn't bend easily, so the outer shell must be proportionally thick. The overall thinness of the cell is its main attribute, especially for slim wristwatches and the like. I just doubt that it's well-suited for a calculator with significant power demands.

-- KS


#42

Our always-on wristwatches run on highly task-specific low power CMOS logic, running at pretty low clock rates (I think most watches count down from a 32768 Hz crystal). Our newer calcs run a lot faster (I suspect even in whatever clock mode they might have) and the power consumption of CMOS (and other logic) depends on the clock rate.


#43

Quote:
(I think most watches count down from a 32768 Hz crystal). ... power consumption of CMOS (and other logic) depends on the clock rate.

Spot on: that's why many embedded processors have dedicated real time clock hardware ( either internal or external ) running of a 32KHz crystal, with the processor core running at a different rate. The main processor can power down or sleep while the real time clock hardware still ticks over.


#44

Quote:


Spot on: that's why many embedded processors have dedicated real time clock hardware ( either internal or external ) running of a 32KHz crystal, with the processor core running at a different rate. The main processor can power down or sleep while the real time clock hardware still ticks over.


Correct.

Lithium coin cells actually have very high energy density for their size and weight, typical capacity of a 2032 cell is 235mAh @ 3V

Low power ASICs like that used in purpose designed watches can last for the shelf life of the battery. A new range of Casio watches claim 10 years battery life.

It is possible to add a Real Time Clock chip to any microcontroller (if it doesn't have one internally) that will last for many years. So it would have been easy to add such functionality to the 33S, but they chose not to for some reason (cost, perceived need etc).

My new calculator has dynamic processing speed, speeding up when it needs to, and slowing down when it's not doing much like waiting for user input.

Dave.

#45

Thanks to all who responded. As some correctly identified, my purpose in wanting a stopwatch/clock built in to the calculator is that it makes for a nice addition to the laboratory. I can write a program that also initiates the stopwatch, and takes the splits, etc., and uses them as input variables for the same program. I am using my beloved 41 for this now, but I am concerned the day it dies of age.

Sadly, it does not look like the 35 will have that capability. Oh well, perhaps I can write a routine to work off the ticks of the crystal.

It is almost like anticipating Christmas.


#46

There is really a pretty simple solution to the problem of the 41c getting old:

Replace in with a 50G.

I believe that Hrastprogrammer has even written his HP41C emulator for the 50G.

Or you can use the 50G (or 48GII) and write RPL code for it. It has the clock and I/O built-in.


#47

I found that becoming proficient with any of the HP RPL calcs from the 48 series on, will provide you an activity that will last till the end of your life. Those of us who are overly fond of the 41 series calcs are usually just looking for simple practical solutions for the problem at hand. Call me lazy. I don't want to study a manual for longer than 10 minutes to solve a problem.


#48

Fully agreed! For this purpose, RPN is superior to RPL. The latter is better for real geeks, but also I won't reach this level anymore :-)


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