Calculator blog

I had just received 10 more units of the flexible adhesive circuit used to repair the destroyed battery bays of many HP41c machines. I put it up in the website at 3h15. The 10 units had flown by 19h00 !

When talking with the producer, I asked him for 15 units more - but he only has 10 for me. I have ordered them immediately.

This is a fantastic part, that has helped to revive many calculators. It is a pity that so many HP41c, for many the best calculator ever, are in non-working condition due to rust contacts. This product is well conceived, elengant in its application, works well and lasts long.. 

This website is devoted to HP calculators, and it is mainly geared towards HP calculator enthusiasts. But this blog issue will not be mainkly devoted just to them, but to everyone.

HP created the scientific calculator business in 1972, when it launched the HP 35 calculator. It is less well known that it also created the financial calculator business when it issued the HP 80. This was the first calculator that included the Time Value of Money formula built in, as well as other percentage-based formulae. That was as early as 1973, and it was its second handheld calculator. The basic difference is that in the scientific model, it was assumed that the formulae would be introduced by the user; in the financial models, the main formulae would be built in for faster results.

Both of these calculator were high end models at the time, with a price of around 400 dollars then; and both were using the Reverse Polish Notation data entry method, which was the only available back then.

Fast forward to 1989. Then, as part of the Pioneer calculator series, HP launchs the HP10b, the lower level of its business series at the time (which peaked with the HP17b). It was continued with the HP10bII in 2000, with the rounded body that appeared when production was outsourced to Chinese third parties. The keyboard click on these, while still miles ahead of everything from the competition, had a plastic feel that alienated many HP users (that could be said as well of all other Pioneer sucesssors, like the HP 17bII+ gold version). The firmware quality did not have the same level of the original HP versions. Since the processor was completely different from the Saturn-based chips that HP had been using from the HP71b and HP29c, the Chinese producer had to redo it from the start. Inferior algorithms were used, although with faster processor. This was much more evident on the HP17bII+: the solver in it is clearly worse than the original. In a way, these models were "reverse-engineered" by the chinese supplier, based on the original design requirements.

But with the new calculator team in HP, a decision was made to produce themselves the firmware thereon. The new team has created the HP30b and 20b, the fastest calculators around; the HP10bII+, using the same body but with many more clever functions; and the HP 39gII and the HP Prime, heralding the future scientific models.

The original 10bII used a single "second" key. As the basic financial calculator, it only had a limited set of functions. The new one, on the other hand, has many more functions. HP has decided to add on top a lot of scientific functions, to the point of making the purchase of a purely scientific calculator questionable. And it is an statistic powerhouse: it has several distributions included, apart from many other statistical functions. Were it not for the lack of RPN, it is vastly better than the HP12c for all practical purposes.

Take a look besides and see how it looks in reality:

As I have been receiving several requests from customers that are willing to buy a HP41CL calculator, I forwarded him some requests. If you have read previous installments of this blog, you will know that all stock of 41CL board for refitting in old 41c were finished by the end of last year, and that Monte did not know whether he would commit for a further production batch.

So far there have been 4 production batches. Each one had either some mods, or additional images written into memory. In my experience, none of them is faulty - all of them can be used and all of them are able to run at 50 times speed. In fact, and provided that you have the requred hardware, you can update it with the latest pac images.

The hardware required is either the serial interface provided by Monte (a cheap solution), or other interfaces like the ones provided by Diego Díaz. I have yet to try his interfaces - but I guess that they will work fine - I swear by the circuit he created to repair the battery bay contacts for the HP41c.

Well, the point here is that this week end I received a mail from Monte where he tells me that there is another HP41CL board batch in production! He wouldn't say if he has implemented any significant changes on it, but it is good enough to know that those of you who wanted them still have the opportunity.

I won't take any orders until I am able to get a suitable delivery time. Stay tuned!

Now that I am working a lot with the HP Prime, using the little tips and user keyboard, I am getting used to the low displacement, clear click of the HP Prime family. "When was the last time I felt a click like this?", I ask myself. And the answer is clear - in the Hp 30b Financial Calculator.

This little machine has never enjoyed the cult status of the other machines: both the 12c/cp family (with their classic keys with three functions in each, and programmable in RPN), or the HP17bII+, with its very good keyboard feel and intelligent solver, which can be turned in a programming language with a little knowledge and ingenuity, have enjoyed a "top" status that the 30b did not reach.

And the 30b is the fastest of them all, and as well the one that has a better set of functions - but that you know only when you have bought it, not before. Its menu system, while not as "beautiful" as the one from the HP17bII+, is well organized, and you can perform solver-like calculations in one of its mini-solver 3- or 4- variables calculator. You can even perform Black and Scholes calculations off-the-shelf - a first for an HP calculator. Both the HP12c and the HP17bII could do it; the first one, fully using the 99 memory steps (in a program made, I think, by Pablo Fernández, engineer and Finance professor in IESE MBA); the second one, via some complex programming of the solver. 

But as well, it is the ideal statistical calculator. Apart from creating lists of points, which is much better that just feeding some accumulators like the previous calculators did (apart from the HP17bii), it has a set of "descriptive statistics", another set of data fit in many types (many more than the ones that appeared in the statistic pacs of the HP 41c), then the typical accumulator set (that we have from the very first HP calculator that had statistical functions) and another set of quartile analysis. If you look at the manual (pages 69 and onwards) you will see all of them in a very clever "function map". 

The front panel is made obviously made of plastic - the metallic aspect, while elegant from far, and resistant to scratches, fools no one. It cannot be compared with the nicer livery of the HP17bII. 

The screen, while much more descriptive than the one on the 12c family, has an alphanumeric upper part (where you see the function you're performing or the place in the menus your into now), and a numvrica part, but not made of dot-matrix characters, but with segments instead. Curious. It is much clearer than a dot matrix display, but it seems odd in these times of "retina" displays.

(I always forget to state that one of the advantages of a calculator is that it is nearly impossible that it runs out of power while you're at a critical situation like an exam. I almost also forget to tell you that it can be algebraic OR RPN !!)

We have lowered its price to 40€. Now we have plenty - probably more than what we could convert to wp34s (which is another of the beauties of this little machine!). I leave here a good picture of it, for you to enjoy.

I have been asked whether the HP30b and 20b are discontinued. While there are still lots of units in the distribution channel, the decision to discontinue them was taken long before. Nevertheless, I am ordering my last stock to be able to respond to wp34s orders – which do not seem to diminish.

The HP20b is the turkey in the financial roster of HP. The HP10bII+ has much better keyboard, a very comprehensive function set, and a good quality feeling. It feels an HP all the way – despite not having RPN entry mode. I have used HP20bs, but I have never stocked them or opened one for myself. If you’re accustomed at any rate to HP calculators, you need to forget that model.

Later models from HP, even being copies from other brands (as the case may have been) have made an effort to get a decent keyboard. The HP30b has exactly the same innards and shares most of the programming, BUT has a decent keyboard. While using a number of the newer calculations, I have learned to like the low profile, low-movement, click-and-rotate keys. These are used, in a way or another, up to the HP Prime. It will never be taken for a HP41 (probably the heyday of HP keyboard quality) or Pioneer or HP48 family keyboards (second best in my opinion, but still very responsive and giving good feedback.

If I was buying a new financial calculator, I would try by all means to stretch to the best there is, i.e. the HP 17bII+. You get a much better calculator from (nearly) all angles. The keyboard quality is better; the 2 line dot-matrix screen, miles ahead of the mid dot matrix, mid numerical screen of the HP30b. The only area where the HP30b show a clear pair of heels to the HP17bII+ is on speed and by having several specific functions that the HP17bII+ does not have, including Black and Scholes and several statistical functions not found elsewhere.

But if I want the best current scientific calculator, I now have 2 options: the HP41CL and the wp34s, which is built around the HP30b. In many cases, the HP41LC will be beyond your reach – for the time being. I still think it has to be the aim to aspire for any devoted calculator aficionado. It is my preferred day-to-day calculator and it is always on my work desk. But I understand that its price of close to 600 € may prevent some of us from stepping in and get one. Or incur in the alternative risk of doing it yourself. (which is a simpler task that it may seem at first sight)

If you have not been into calculators for the past couple of years, I will explain (again) what a wp34s calculator is. There has been an open project to repurpose an HP calculator (in this case the HP30b, but there have been essays with other machines like the HP12c (Atmel-based version)), including the best available software and using the processor memory up to the top, including ll kind of mathematical operations and constants. The output of this project, led by Walter Bonin and Paul Dale (at the beginning), later joined by. The software passed through many iterations, probably several thousands (I stopped at more than 3k), and it improved substantially. Some aficionados even made several hardware modifications, to allow for USB interfaces, infrared printing, etc. The original machine was conceived as an open platform that happened to be very modifiable. Many firmware modifications were made in order to increase code compactness and thus add more functions. If you want to take a look at the complete set of features, you may download the latest manual from this site – and be surprised by the wealth of capabilities: many statistical distributions, in three forms (direct, inverse and cumulated); complex number calculation; your choice of a 8-line stack or 4 stack; all kind of mathematical functions (Bessels, etc. Too many to be described in a blog post), and up to 34 digits of accuracy in double precision. The ideal mathematical machine!

Well: all this drivel to just say that the stock of HP30b has just arrived – and we can prepare as many wp34s as you may need!

In the www.hpmuseum.org site, which is probably the website most popular when it comes to HP calculators, Han has published a couple of very interesting tutorials for Prim programming. 

You can find the first here: HP Prime Programming - An introduction

It shows the answer to many questions I have faced when starting to program. Questions that imply that Han has a deep knowledge, not only about the manual, but about the behaviour of the machine. There are many things that do not appear in the manual but are the result of testing and failing or succeeding with the calculator. 

A comment that can be made is that most of the explorations have been made with the calculator emulator on the computer. There are many things that can be done quite easily using your fingers on the calculator screen, like bringing variables to screen, executing programs, etc. For example, when he speaks of the several methods or running a program, he does not cite the one I use most: locate the program with the fingers on the toolbox menus! That said, I have learned a lot of things about the Prime when reading it, and it is for me probably the best introduction to programming the HP Prime.

The new software used for the forum in hpmuseum.org allows to easily include code snippets, that do not occupy substantial space but scroll in the mini-window allocated for them. This is quite convenient to copy programs to illustrate a point, without interfering with the reasoning behind. This is used by Han to very good effect.

There is already a continuation in HP Prime Programming: Variable types and their priorities

The current batch of HP 41c battery connector repair kit are leaving us much faster than the first time. There was a comment in the web, whereby the user found that it was quite difficult to find the product in the search engines. I will now put it as first in the accessories list, so that it is easier to find it in the web; and also will announce it in google adwords.

If you have not seen it, I will make a brief description of it. If you have seen HP 41c/cv/cx in internet, you will find that a good number of them have rusted connectors. In many cases, this rusting impedes connection and therefore the calculator does not function. Many otherwise good HP 41c are not used and sold at discount prices, while the rest of the circuit does work (there are very few calculators that have a real circuit failure - it is either the connectors or the screw posts that are broken and do not provide enough pressure)

Diego Diaz designed a printed circuit in a foldable, adhesive material, that can be used to replace the original, rusted one. He has also prepared a short instruction sheet that make clear how to do it. So far, all users that have bought it from us have succeeded. The HP 41c repair kit is for everyone!

Be sure to download the instruction sheet that you can find in our website to make sure you don’t spoil your repair kit circuit.

You can see in the pictures that the result is impressive. However, I think that it is important to follow the instruction to “cook” it at 90º, so that the bends in the flexible circuit remain.

It is a pity that so many calculators are thrown out and discarded, when a fast, clean and elegant solution is available.

Should you think that it is still too much for you, you can try contacting us to do the repair for you at sales@thecalculatorstore.com, if you are in Europe, or to www.fixthatcalc.com if you are located in the US. They have fixed rates for repair, while we do prefer to see the calculator and then quote (in many cases a few pictures will suffice)

The HP 41c is the most successful calculator in HP’s history. While HP has never revealed the total number of 41s produced, it seems to be week over the million. Due to their robustness, many of the are still in use. And due to its easy programmability, they can still be used successfully for many applications where a graphic calculator is not required.

Apparently, the HP Prime is starting to get software!

There is a specific HP Museum forum, in this URL, where the users post their software. Now, you need to know that HPmuseum, as its name suggests, has been basically geared towards old HP calculators, and preferably pre-RPL too. So HP Prime is several generations newer than the average subject there. However, most of the forum members are science professors, engineers and scientists, so they enjoy programming. Basically, what you can find there is mostly technical and quite advanced - but you can find too several utilities that improve the connectivity with the Prime.

There is a forum specifically for the HP Prime in general, and another one for software in particular.

In the software page you cannot find now a single game - but they will soon appear. There are several programs that use recursivity to calculate several fractal compositions, and several other graphical curiosities, using formulae with fascinating properties when graphed. 

The success of the HP Prime in the student area will depend on the availability of user-developed software.

If you look to any TI-related site, you will see a wealth of software created by users, and that can be used by students for their own work. This has helped a lot to get as wide marketshare as they have.

The HP Prime is faster than most other calculator, thanks to its compiled basic. The graphic functions of the HP Prime allow it to produce good games - even in Basic. There have been several simple programs made in Basic where students can see the code that produces such results. But I think that other languages should be available for Prime, so that serious programmers put their hands on the machine. And there should be some money to be made by programmers, if anyone apart from amateurs is to be involved.

Can there be a market for apps, organized in the same way of the iOS App store or the Android App store? Width and breadth will be far from them, but some clever programmers may make some money and therefore be interested in developing for the HP Prime.

Can I share with you which apps I would like to have?

• An app that make the HP Prime to act as a numeric keypad for a computer. Apart from the numeric keyboard, there is a very useful up-down-left-right button, and several writing aids can be programmed with the user keyboard. The USB connection is there!
• A financial suite. We have written some programs for that, but it is still far from what is achievable - in particular when integrated with the spreadsheet app.
• Games! If you want to make sure that youngsters buy the Prime in huge numbers,you need to make sure that there are game apps, much more comprehensive than what we have now. While the screen definition is not “retina”-level, is still very capable for creative graphical applications.

HP Prime - possibilities at school.

There are several possibilities opened to the schools when it comes to technology in the science class.

On one side, you have the ubiquitous tablet. It is excellent for everything, and it can substitute all books. It can also act as a technical/graphical calculator, with the suitable software available in the web.

On the other hand, its own openness and capabilities make it unable to be used in class. There are no possible settings in a tablet that can impede its full use for someone that knows a little bit about the system. Tablets cannot be used in exams - period. Or you need to design the exams around the tablet. I remember that we had an algebra professor in my engineering school that made tests that lasted 2 days, with just 4 exercises, one for each morning and afternoon. This professor allowed all calculators, books, and class notes that the alumni would like to take with them; and yet, in the june tests, 9 out of 417 alumni passed - so it can be done.

Also, the tablet is the ultimate game machine. I would not allow my kids to take an iPad to school, lest they use their whole free time (and most of the not free) gaming. (This is a reason to make me think twice when opening a page about HP Prime games. The main difference here is that it may encourage boys to program their own)

Lastly, the tablets are quite limited when interfacing with other things, like sensors, etc. (Calculators too, with some exceptions)

The HP Prime offers an integrated educational environment:

• It is a self-contained math machine
• It is programmable - what a tablet is not. A student can understand the logic of programming.
• The programming language is easy to learn. While most of us would agree that RPL is more elegant, it is also much more difficult to learn.
• It has an exam mode, whereas the features of the calculator can be adapted to the specific exam requirements. You can sent what the calculator can do and cannot, and you can do it centrally.
• The teacher can see what happens in each and every calculator screen of his pupils, with standard HP software.
• The machine can be connected (with the Streamsmart 410) to a list of Fourier probes, which make it a mobile lab, if you will.