If I was asked what was my all time favourite "gadget" I would have to answer my HP-41CV calculator... not only did I have a highly portable fully programmable device but it also set me off on my IT career! Most notable is that I have sold off just about every other gadget and phone over the years but there was never any question of letting go of my trusty HP-41CV.
I got this calculator when I was studying engineering at university in 1983. I seem to recall my father organising it through an uncle of mine who worked at Hewlett-Packard at the time, who got it at a staff discount for me. I was over the moon when I got this device and it really opened the world of programming for me and testing out what I could do with it. HP had a whole ecosystem of quality accessories, had the Key Note magazine that helped build the HP users community, etc. The Solution Books allowed you to type the code in yourself to add new games and functionality - this may sound elementary but is vitally important as it was essentially open source code that showed me how games and applications worked so that I could apply similar techniques in programs I designed myself. They had also standardised on RPN for calculating (which is extremely powerful) as well as various accessories which were way ahead of their time. Of course with an HP41C going to the moon at the time, that only served to further enhance its image. These calculators were drop tested 1m onto concrete and were built to really last - most are still running today after 30+ years. Yes I'm trying to source some N size batteries to start mine up but I have no doubt it will work.
The career changer for me was that after university I joined the police (because back then we had to do national service in either the Defence Force or Police) and one challenge for the guys was wanting to know what shift (a morning, afternoon, night or rest day) they would be working on some future date (eg. Christmas, their birthday). So I wrote a program that would quickly work this out. Needless to say I was a big hit and the "go to" guy to find this out quickly. Later on when the Information Systems IT Unit was being formed in Cape Town the Colonel in charge of my unit called me in and said I was submit my request to go to IT as that is where my future lay.... and it all happened from there thanks largely to having a device like this.
The photo album shows various accessories that I bought including extended functions modules, a rechargeable battery pack, a magnetic card reader (so save and reload programs), solutions books, manuals, and HP Key Note magazines. One extra photo is included on the excellent go41cx emulator for Android (see market.android.com/details?id=o2s.emul.hp41cx
). This emulator faithfully reproduces all the functionality of the HP-41CX including add-on modules. I'm busy practising on this emulator in preparation to being able to start up my calculator soon.
The original HP-41C was fully functional and could accept any additional function modules, and the HP-41CV had some extra memory built in , whilst the HP-41CX had the extra memory as well as the Time and Extra Functions modules already built in. The extra function and memory modules along with full programmable capability meant these devices were very hardy and future proof - you could spend the money as you were investing in something long term that you could extend along with your needs.