My pocket computer from high school – Sharp EL-5500 III

Yep.  I was the kid who had a “pocket computer” in class when all the other kids just had a simple calculator.  I was recently going through some old moving boxes and found this beauty:

Sharp Scientific Computer

(click for full size)

It’s a nice scientific calculator on the one hand, but on the other hand it’s a pretty capable programmable computer.

I loved this thing.  I used it in high school and junior college and also during my first year in a 4 year engineering university.  I remember using it at the university during my first year there because it actually got stolen by a kid a few doors down in the dorm and the campus police found it in his backpack and returned it to me because my name was etched into it with an X-ACTO knife.  I etched my name on the back and also etched my initials in underneath the glass display cover so it could not be easily removed or rubbed off.  I’m awesome that way.  🙂

So I used this thing for probably four years between about 1987 and 1991.  About that time, the HP RPN and graphing calculators were all the rage at the university and this old workhorse was put away in a drawer.

This thing used BASIC for it’s programming language.  So it was pretty easy to program.  One limitation was the single line output screen.  Because of the single line, I had to get creative with my output formatting, sometimes, in order to push a lot of information to the screen at one time.  The other thing I remember is that it only stored one program, and I did not have a means to transfer programs to and from it.  So I always kept one giant program on the thing with a start-up menu that allowed me to run a different part of the program based on what I wanted to do.  So I merged many different programs into one and every time I thought of a new program to add to it, I had to add it to the start-up menu so I could select it to run.

One really nice feature that was built into this device was the matrix math capabilities.  I could create very large matrices, and it would step me through filling in the values then it could perform transformations and math functions on those matrices.  I used this feature a lot during some of my engineering and math classes.

Here is a short web article on it:


And here is a guy who figured out a way to record the program dump from it to his Laptop as an MP3 file, rather than the standard means of recording it on a cassette tape player:


Cool stuff.


One thought on “My pocket computer from high school – Sharp EL-5500 III”

  1. I have one like that and I create animations with wait and print and I impress the students of my classroom and they say “how a calculator can do that”

Leave a Reply

Your email address will not be published. Required fields are marked *