[johnea]

A friend and I also made this!

We used it as a speed dialer that worked on any phone.

I still have the hard copy of the synthetic programming guide!

Even outside of that technique, the calculator was a very powerful programmable tool for the early 1980s.

The same friend and I also wrote a program for performing all of the calculations for a grad class in S-parameter modeling of RF transmission. We were so proud, we showed off the program to our professor. Our "reward" was having calculator "programs" banned during all tests 8-/

We didn't realize until later, that there was a "turf war" going on between the RF section of our EE department, and the digital electronic section.

This is how the HP-41CX calculator helped me learn one of the most significant lessons of my EE degree: when it comes to human decision making, the tech is often far from the top priority.

[anonymousiam]

Great stories. I had a similar experience with one of my college math professors (I was 16). I showed her that my calculator (with the Math module) could transform a 9th order matrix in a few seconds. She shrugged, because she knew that I didn't need the calculator to ace her tests.

The dialer was one of only two mods that I had made to my 41. I brought out the piezoelectric wires via a two-pin female .1" "berg" connector that I had added to the lower right side of the case. (I wish I had a photo.) The other mod used similar hardware; I put a magnetic reed switch inside, which changed a capacitor value for the system clock when a small magnet was attached (via Velcro) to the side of the calculator. The result was that my 41 would run its programs twice as fast. I had to remove the magnet to use my auto-dialer, because otherwise the timing was wrong. In my area, GTE didn't switch to ESS for another 10 years. Oh the fun!