Raspberry Tea

I am writing this on my Raspberry Pi, which is currently hooked up to my monitor at work (it’s now my lunchbreak and I’ve, once again, successfully resisted the temptation to play with my Pi all morning).

As I mentioned the other day, my first attempt at directly hooking up the I/O hardware (rather than going in via SSH or VNC to a headless setup) failed because my HDMI cable and DVI adaptor combo was too big to fit in the space at the back of my monitor.  I suppose the proper geek solution to this problem would have been to dismantle the cable and adaptor and see if I could wire them together directly and make the whole thing short enough to fit.  Instead, I opted for the slightly-less-exciting but also considerably-more-likely-to-work-without-frying-myself-or-my-monitor approach of buying a new cable with a HDMI connector at one end and a DVI connector at the other.  This has now arrived and works fine.

My Pi is beautifully quiet compared to my desktop PC, as it has no fan to make lots of noise (the chip is sufficiently cool-running not to need one) but it’s also noticeably slower (as it has a lot less memory and probably a much slower processor), so I won’t be trying to persuade my boss to let me replace my office computer with a Raspberry Pi, nor ditching my home PC in its favour.  However, it’s certainly an excellent little bit of kit for the price.

I’m still trying to think of actual GPIO based projects that I might want to use in real life, but I’ve now come up with an idea that is at least a step up from just making LEDs flash in pretty patterns.

Several  years ago, I wrote (and then, over the space of a few years, gradually modified) a simple little tea timer script.  As I recall, it started life as a shell script but was soon reworked in Python and has remained in that language to this day.  There are plenty of tea timers in existence but none of the ones I could find did quite what I wanted (which, initially, was mostly to allow me to run it from the command line without a GUI environment to hand, although I later added a GUI option too).

My script works reasonably well and I still use it occasionally, although these days if I want a countdown timer (whether for brewing cups of tea or other purposes) I usually reach either for my mobile phone or my mechanical kitchen timer.  However, one problem I always found with it was that it’s all too easy to miss the alarm bleep and the console message or dialog box that appears when the timer is finished.

It occurred to me the other day (or perhaps it was this morning?) that a nice shiny LED to indicate when the tea is done would be a lot more eyecatching and, with the Raspberry Pi’s GPIO facilities, it wouldn’t be very difficult to set up.  In fact, I’m intending (once I get home to my electronics stuff) to rig up two separate LEDs – one (probably red) to shine while the timer is operating (to show that it’s working) and the other (probably green) to switch on when it finishes.  I may further refine it by making the first LED flash as well if you don’t switch the timer off after a minute or so.

Due to the nature of the hardware and software involved, it’s unlikely to be possible to produce a very accurate timer, but it certainly should work well enough for purposes such as brewing a cup of tea.

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