☰ Human - Use Experience Analysis

HP 50g Graphing Calculator

Introduction

The HP 50g Graphing Calculator has been widely known in the scientific and engineering worldwide community since its launching back in September 2006. It was developed and produced by the company which gives its name, Hewlett Packard, to be the successor of the HP 49/50 series graphing calculators. These high-end calculators feature both algebraic and RPN entry modes, perform fundamental calculus operations, vector operations, matrix operations, numeric equation solver, plot bi and tridimensional graphics, among many more functionalities not supported by basic scientific calculators. The range of customer segments of such product is pretty wide as well, going from high school students to academic and professional users, even though the target customer segment is indeed the scientific and engineering community.

In this analysis, we shall describe and rate the quality of the human-machine interaction when it comes to the HP 50g. How well it attends to its users necessities, how intuitive/user friendly is the user interface (UI) and also how practical is it for daily use. Furthermore, the volunteer users may also point out aspects that they liked, disliked, and in the last case, how would they make it better.

User Interface Summary

The HP 50g Calculator UI is divided in 6 main sections:

User Experience

In order for the user experience analysis of the HP 50g to be complete and properly fair with the intended designed features of this particular product for its target customer segment, the analysis will be based upon the results of two distinct user experience tests: the familiar and non-familiar user experience test.

Test Breakdown

Each volunteer will be asked to perform the following tasks:

  1. Turn the calculator ON
  2. Perform a simple sum operation: X + Y = Z
  3. Perform a simple product operation: X * Y = Z
  4. Perform a simple division operation: X / Y = Z
  5. Save the result of the division operation to the calculator memory
  6. Retrieve the result obtained in the sum operation and raise it to the power of the result obtained in the product operation
  7. Retrieve the saved result of the division operation and subtract the result of task nº 6
  8. Get the absolute value of the result of task nº 7
  9. Reset the calculator memory
  10. Clear the calculator display
  11. Turn the calculator OFF

User Experience Test #1

Representing the non-familiar user volunteer, we have Mariela Klann Fonteyne, a 48 years old women, graduated in architecture by the Universidade Federal de Santa Catarina (UFSC), mother of 3 boys, who currently runs a architecture firm in Campinas, SP, Brazil. Before initiating the test, I made sure that she had the required mathematical knowledge in order to perform the assigned tasks.

Mariela made through the first 4 tasks with ease. She mentioned to be a little confused about not having a "=" button as commonly seen in simple 29 button calculators, but she rapidly figured that the "ENTER" button would be the corresponding button in this calculator. However, after the 4th task, she failed almost all of the following ones. The only two tasks she was capable to accomplish - after some hints and a lot of difficulty - were the 10th and 11th.

When I asked her what could have been the reasons for such difficulty with the last 7 tasks, she answered that it was mainly due to the "visual pollution" of the calculator interface. "There are just too many buttons! And because of that, every single time I attempted to try a new button that would lead me to a new screen that wouldn't help me at all, I usually ended up stuck there because I had no idea of how to get back to where I was!".

User Experience Test #2

Now, representing the familiar user volunteer, we have Felipe Giardini, 21 years old, undergraduate mechanical engineering student at Politecnico di Milano, Milan, Italy. Felipe has been using his HP 50g for the last 4 years of his undergraduate program, and therefore, Felipe managed to complete the whole task list in less than 2 minutes. Nevertheless, when I told him about the difficulties that Mariela had when she tried to perform the same tasks, he recalled of his early days using his HP 50g: "As far as I can remember, performing the basic operations have never been a challenge for me, but I do remember of struggling a lot when trying to save and retrieve values from the calculator memory, probably because it is completely different from the way that all ordinary calculators work. Also, getting stuck in new screens whenever I accidently hit a button, or even when I am trying to discover a new feature, is still a occurring problem for me. Even after 4 years of use, I still do not fully understand how this back and forth navigation system works.".

Human-Use Experience Analysis

Overall analysis

Considering the target customer segment of the HP 50g to be the scientific/engineering community, this calculator is definitely a great deal. Even though it can be often misjudged as a bad design for its numerous amount of keys and functionalities, what inevitably makes it not super user friendly, this loss in intuitiveness is the price you pay for being able to provide your diverse range of users - varying from high school students to high-end scientists and engineering researchers - with all the functionalities they might need.

Besides all of that, when evaluating this calculator under technical parameters, its performance is also nothing but of high excellence. It has excellent keypad feedback - what for calculator is crucial -, great battery life, it is fairly light, fairly good portability, very robust and safe from accidental drops, has more than necessary internal storage, 2 serial ports for external communication and one SD card slot for storage improvement, among many other qualities.

Aspects that could be improved

  1. Display

    As the overall screen technology advances throughout the 21th century, we progressively get more and more fussy with the display quality of the devices that surround us. This 131x80 px BW display makes you feel this is a calculator designed back in the 70's. Due to its terrible resolution, sometimes it is even hard to differentiate some special characters when using small font size mode. Not to mention that this a cheap and very easy improvement to be implemented.

  2. Build Quality

    It is quite frustrating whenever you pay a price that is just not fair for what you are getting in terms of build quality. This calculator definitely is one of that cases. If only the body shell material could be a little more premium and durable than the current one, the user experience would definitely feel a lot more exciting.

  3. Navigation System

    This is by far the aspect that most annoy both new and long term users of the HP 50g. The navigation system is not only often very confusing - as pointed by the user experience tests 1 and 2 - but also many times slow and exhaustive even for expert users. As possible solutions for this matter we have:

    • Give the ON/OFF button of a different color, indicating that this button performs a different type of action then the other black buttons located next to it
    • Make the ENTER button larger. As this is a very commonly used button - after all, every single time that any user is performing an action, he/she will eventually press enter to get a result -, it seems fair to try to highlight it so that users can easily find it. In addition, we can notice this good understanding of the importance of highlighting a very frequently used function, in the normal calculators, where you have a considerably larger "=" buttons when compared to the +,-,x, etc. buttons
    • Reallocate the CANCEL button. As pointed out by the users in the user experience analysis, being able to "go back to where I was" is a very common issue among the users of the HP 50g. That definitely is due to the terrible location of the CANCEL button. Currently, it is programmed to be accessed through the same button as the ON/OFF function, and its indication is a dark blue subscript on the extreme low-left corner of the calculator body, literally almost impossible to find if you have not been using this calculator for more than a month - optimistically speaking. That said, a great and really simple solution would be to add an exclusive CANCEL button right next to the navigation arrows on the mid-right end of the calculator body
    • Enable repeatability when holding down keys. One often forgotten but really important capability of a product destined to professional use is agility. As a calculator which its target customer segment is the scientific/engineering community, which uses the HP 50g as a daily working tool, agility is crucial and always very welcome. Therefore, enabling continuous repeatability by holding down a key for a short period of time, can be extremely handy and time saving in built-in apps like EQW and CAT
    • Separete each UI section in a more clear way. Even though the HP 50g tries to use different color tones as well as button shapes and sizes to make easier for the user to distinguish the 6 UI sections, this separation is often not very clear - because of the inconvenient similarity between the "different" button colors and shapes - and also sometimes even confusing. For example, following the key color/shape pattern suggested by UI, the backspace button seems to be part of the advanced mathematical operations section, but actually it would make much more sense if it were assigned to be part of the screen navigation section instead. Thus, regrouping these sections in a less confusing way, plus adding different colors, shapes, sizes, etc. to the buttons or even the body shell is a quick and very effective way of solving this issue;

References

Nicolas A. K. Fonteyne