Show current content as RSS feed

Calculator blog

Musings and comments about our common interest


621 - 630 of 644 results
Published on by

More news about the site

There are some news about this site that I would like to share with you.

New Products

I have found several "old" products that will be published in following days. These include 3 classic machines, 2 woodstock, 1 clamshell, manuals and chargers. Some of them are in really excellent state, and come with boxes and other accesories. I am in the process to test them, clean them and take pictures.


There are already three units being sold - taking into account the apparent risk it may involve (in reality there is no significant risk - the machine works wonderfully). This means that I have posted 2 contributions to the project, and an additional one when I get the payment for the new one.

There is a local calculator hobbyist to whom I have lent one to try - sorry, this is something that can only be done locally and if you trust the person. I have met this individual a couple of times and seen that we share a significant number of things  - from the business school we studied to our other hobbies (music and Hifi, anyone?)


(here comes a rant)

I had a long discussion on calculators with him. When coming back from the meeting, I reflected on what makes me tick with a calculator - and I have to acknowledge that, in my case, it is the machines that I have used in the past. In that respect, the wp34s has everything I might want on a calculator (except perhaps matrix tools), but is a little too difficult to work with. And I tend to come back, time after time, to the dumb old calculators that were easy to use to me - the HP17bII and the HP19bII. The HP17bII is current, the 19b is not - and it is a pity. The 19b has all the trigonometrics and mathematic tools that the 17bII has not. In addition, has the 4 lines on screen (3 lines plus menu line)

An idea for HP - you have mastered the HP17bII in its latest version. Why not add the 19bII features that are missing in the HP17bII? (Now the HP17bII has a problem: the HP30b has true programmability, Black and Scholes already written in firmware, and a lot of mathematical functions missing in the HP17bII. It even comes with a clever menu system. I still feel that the ease of use of the 17bII is superior to any other calculator by HP or by any other brand for that matter - but someone should do something to ensure thet it remains at the top of the heap (or should I say "the top of the stack")


By the way, I have not posted the black one yet.


Last Friday I re-installed some SEO tools in a new computer, and connected to the website. Until now, and due to the fact that the site is quite new (since beginning of February), we were not classified (i.e. the ranking of the page was zero). Most of my local competitors were 0 or 1 as well - this means that their only chance of getting traffic is through adwords. Well, this Friday I saw that we were 3 !!


This is still miles away from's 5, or's 6. (It is worth noting that hpcalc has as well a sales site for the US, whose ranking is 4) These sites offer substantial information apart from sales, and the ranking is well deserved. I myself delve into their pages when I need to find information or software. I aknowledge that is still very far from them. We miss both the time they have spent over the years (on one side), but as well the expertise that people like Eric Rechlin possesses.

There are 2 ways of getting visits: either you pay a significant amount to a Search Engine Optimisation company, or you take the difficult way of adding more and more pages of relevant content. I have chosen the second way. However, it requires a significant amount of your free time, both looking around for interesting content, imagining what can be of interest to my fellow visitors (that's not too difficult - I just need to put whatever pleases me, and plain hard working to put it down to the screen.

That said, Google offers a wonderful set of free tools to manage your website, but the information it gives is some times inconsistent, jumps up and down for no reason that I can explain, and leaves you downfounded. How are we going down on this and that keyword, and going up on these others, if we have made no changes regarding any of them?

In any case, I am enjoying the hell of it, and learning a lot in the process. 

Other news

Finally, there are still no news about new products that I can release. Please observe the careful wording of the sentence - even in the avoidance of keywords that may give away more information than needed !!

When the time comes, we will send a newsletter to all registered user. You do not need to buy to register, and the current registered users know that we do not spam - in fact we have not sent any newsletter as of late!!


Read entire post
Published on by

WP 34s just born


I received this week the overlays from Eric Rechlin. Wonderful quality and choice of material. You cannot touch it from where you are - believe me that feeling is good and adherence superb:


I have received several overlays. I plan to set the complete kit: the flashed HP30b + the overlays. Just to Europe to avoid competition with Eric; and 10 € of each sale will be donated to the wp34s project.


Now, let's see the machine under surgery:


It was updated with the latest available build, 1125 at the time:



Now, let's see how it ended up:


Sorry - the light condition was low and my pulse unstable -> fuzzy picture.

This one is better:

When you do it, do not try to fix it with a hard thing - see the mark over the CLx key.

I learned from it and the rest of the keyboard was excellent!!

It really looks professional, and the key feel is much better than the HP20b.

Now, let's try to work with it and make some programs !!!

Read entire post
Published on by

Black HP17bII

I have just received the black HP 17bII that I had been looking for.
Does anybody know when these units where made? The pictures herebelow compare it with another calculator with the typical, uglier colours. Both are made in Indonesia,but you can see the difference. Even the pouch is black instead of brown, and seems to be of better quality:

I have just received the black HP 17bII that I had been looking for.

Does anybody know when these units where made? The pictures herebelow compare it with another calculator with the typical, uglier colours. Both are made in Indonesia,but you can see the difference. Even the pouch is black instead of brown, and seems to be of better quality:

Read entire post
Published on by

New video tutorials for HP50g, HP12c

We have started to include video tutorials for some of the most frequently sold calculators.

These videos have not been created by me. I have selected them from a surprising amount of information that can be found in the usual video sites.

A video tutorial is no substitute for a proper read of a proper Hewlett Packard manual, but helps when you just have received the calculator and want to get started with minimum fuss.

Here are the 2 first pages that sport video tutorials;

HP 50g Tutorial videos - English

HP 12c Tutorial Videos

It is interesting the introduction made on RPN. Here is preaching the convert, but in the wild, it may help to convert some. It is just question of getting hooked!

We hope to introduce many more in due time...

Read entire post
Published on by

More about the Multi-Language software for the HP50g

I have received today a message from Andreas Moeller, an innovative programmer, and author of a set of tools for the HP50g.These tools include a full translation of menus, flags, and applications to the language of your choice, and an equation tree builder which is extremely useful for those that have several equations and several subdirectories in their HP50g.

(by the way, a disclaimer - we sell the HP50g with the multilanguage as a pack - and we include with it an SD card)

Andreas has been working to make its software known. We have a difficulty here: it is hard to convince a student to pay for something when he is accustomed to get everything for free - and students make 95% of all purchases of HP50g. (users are more varied - eventually the student earns his grade and starts working, keeping his calculator with him). One way he has trie is creating some videos that explain how the software works.

Here is the example about the multilanguage pack:



Equation Tree Builder

I am enjoying the full set of tools in my HP50g. It is saving lots of time in my work. When I need to find where is the nice equation that I wrote 6 months ago (how did I name the equation? What did the variables mean? Under which assumptions does the equation work?

Here is a video that shows how the tree browser is used



You can even organize your own sets of equations and transform them into programs, or even libraries, to be distributed to your friends and colleagues. Here is a video that shows how:



All in all, an excellent software, and for me (in particular the treebuilder), verging on the indispensable. Highly recommended !!

Read entire post
Published on by

N.O.S. power supply for HP82240B

We have found some new old stock (NOS) HP F1011A power supplies, for UK plug.

It is amazing how the printer transforms itself - printing is much faster and you no longer feel sorry for your printer on long program printouts.

By the way, it seems that our old infrared printer may be used as well for other, non-HP equipment - in particular Testo analyzers

Read entire post
Published on by

Now TheCalculatorStore is visible on your smartphone

From the end of this month, you can try to access the website with your smartphone and the view will be optimised for it.

There are still some quirks to be ironed out, and verbose descriptions that do not have a place there, but you can now read this blog through your 'phone!

Read entire post
Published on by

How I have configured my HP15c for financial duties (IV)

Finally, I include date calculations. The one I use more is the HP12c's DDAYS operation. I then set to find in the web software for it. I did not find it for the 15c, but I did for the 42s, that I then adapted. Attention - it has been modified to cater for European date format: dd.mmyyyy - you will have to go to the part where it decomposes the number into the parts and then change a few lines there.

The strategy is just to convert the date format to Julian number, convert the other date, and subtract. Fortunately, the DtoJ subroutine does not consume all 4 stack registers - or we would not be able to subtract them!

Once entered, you will still have 16 registers left. (we assume that we have set 11 registers for program use: from register 0 to .1 (so that you can enter the investment + 10 years + the number of years for the IRR program seen in past article). These 16 free registers allow you to invert a 4x4 matrix, or to solve 2 equation systems with the same coefficient matrix (a typical thing when you're solving structure problems - you apply the same set of linear equations to different conditions)

Here it is (and I have finished with it. The only possible addition would be the DATE+ function. The D->J is a part of the DDAYS program; We would just need to create the J->D - at the expense of losing necessary registers!)



Read entire post
More about: HP 15c, hp15c, hp15c+
Published on by

Selling in Pounds!

We have finally found a way to distribute our products in UK. We will have local distribution and therefore a flat transport rate of GBP 7,5. The pricing will not be exactly exchange rate times the € price; as we will be sourcing locally, some prices will be better than others (it is quite difficult to match our price for HP50g in mainland Europe!), but in the comparisons we have made, our prices are very competitive.

The feedback that we received from our British customers stressed that they felt "isolated" from the rest - no pun intended! No more.

We will sell in pounds only the calculators sourced in UK - all other products (for example, calculator flashing - and the associated calculator) still need to be sourced in mainland Europe and will continue to sell en Euros - basically it is not a question of currency but of price level.
Read entire post
Published on by

How I have configured my HP15c for financial duties (III)

The NPV and IRR are other favourites. There is another program in the Advanced Functions Handbook, that allows for up to 24 groups of cashflows (assuming you do not have any other program in memory!) and using 68 steps. However, as I said before, in my company we limit Capital Expenditure Proposal analysis to 10 years, so that I set to make a shorter program for 10 cashflows.

Register 0 is for the initial investment. Register ,1 contains the number of years to calculate (good to limit the loop and increase speed). Registers 1 to ,0 contain the flows of each year.

The system takes X as discount rate (in %). It can be then used to find the IRR through the Solve feature, entering a bracket of guesses in X and Y.


Now we come to a weighted average calculator. In many occasions I need to get the average margin of all the brands we sell.

But the weighting in HP12c works inverse as I would do. It calculates the average of Y weighted by X, instead of the average of x weighted by Y.

The calculators is mine and I do as I want with it ;-), so I will put it here, together with a cash discount calculation/comparison. We assign the weighted average to the same key, i.e. GSB 0:

One of the typical decisions in my job is to decide on cash discounts - both when buying and selling. I want to compare the cash discount % with a yearly rate - and then decide. I put the standard payment days in Y, and the discount % in X, and get the equivalent yearly interest that I am getting (if I'm buying) or I'm paying (if I'm selling)

Here it is:



Read entire post
621 - 630 of 644 results