I thought I would write down a brief history of how I came to own *six* Hewlett Packard calculators. This was really as much for my own interest as to provide any great insight into nerdery.

I still recall being awe struck when my father came home with a Rockwell Scientific Slide Rule he had bought to use at work. This was truly a thing of wonder - it had red LEDs and it could work out sums! My own first calculator was a Sinclair Cambridge which came in a case that resembled a Star Trek communicator and you could actually see the numbers flicker with the sheer effort needed to calculate a sine. It was a great toy and I still have it and it still works - something of an achievement for a Sinclair product.

I got my first HP calculator in the summer of 1982 after my first year of studying engineering at the University of Dundee in scotland. My choice of calculator turned out to be prescient as I chose and HP-15C over the HP-11C and the next year’s maths syllabus introduced me to matrix maths and the calculator was a God send. It didn’t avoid having to do the calculations but it was useful to be able to check things. The 15C was equally useful all the way through university and the first couple of years of my working life.

At that point I made one of my strangest decisions ever and decided to sell the 15C because I had started working with digital designs and software and wanted to have base conversions available. This was not a particularly daft move but I chose to buy a TI calculator and really couldn’t get used to it after years of using RPN. It probably wasn’t a bad calculator but I needed to get back to the one true faith. At that point I bought an HP-42S which I have now used for years very happily.

I do think the 42S is a great calculator but there is something fantastic about the form factor of the Voyager series calculators. They are small, pocketable, well laid out and run forever on a set of batteries. I was very lucky and had sold my 15C to a friend and he was quite happy to give it back to me as it was gathering dust at the time. I did highlight to him the silly prices that were being paid on eBay for HP-15C at that time but he very generously returned it to me.

This brings me into the ‘backup’ phase of my collection when I realised that I can only really use HP calculators but don’t like any of the modern models so decided to stock up on a few older models from eBay when something reasonably priced came up. So over the next few years I picked up an HP-41CX (classic design but haven’t ever adapted to the layout of the algebra keys), an HP-16C (niche product) and an HP-28S (let’s just say we don’t get on).

The most recent phase is that I thought I should ‘retire’ the two that I use all the time, the 15C and the 42S and all the backups. Given the amounts of money these calculators are now selling for on eBay it seems a little crazy to be using these things at work in an open plan office environment. At least at home I’m insured. The iPhone emulators for the 15C and the 42S are excellent and James Thomson’s PCalc is an good all-round calculator with an RPN mode.

Still, it is nice to have a physical calculator in your desk. So I’ve just picked up an HP-48G off eBay!