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Debugging with cell phones

Saturday, July 11th, 2009 by Nigel Jones

If you walk in the door of a doctor’s office here in the USA, the chances are there will be a sign admonishing you to turn off your phone. Most people probably assume this has something to do with common courtesy – and I’m sure that’s part of it. However the larger issue is the fact that cell phone transmissions can play havoc with an EKG.

What’s this got to do with embedded systems? Well yesterday I was trying to debug a piece of code – only to be faced with a debug environment that would just randomly crash, taking down the debugger with it. Naturally my first thought was that I had made a stupid coding error. However, after some serious head scratching I noticed that I had placed my Blackberry down next to the ribbon cable leading from the emulator to the target. If a cell phone can mess up an EKG being performed 10 m away, I’m sure it can really do a number on a high speed debugger interface when it’s a mere 10 cm away. In short, not a smart idea. Removal of the cell phone solved the problem.

What’s the lesson here? Well the obvious one is that cell phones have no business in a laboratory. However, upon reflection there is a larger issue. I take great effort to make my code as hygienic as possible. However, my workbench is usually a disaster area with extraneous stuff all over the place. Maybe it’s time I literally cleaned my act up in this department. If I had I’d have noticed the phone a lot sooner.


One Response to “Debugging with cell phones”

  1. Cody says:

    You know what? I don’t think you would have necessarily noticed it sooner. It’s something that’s easy to miss. All the more if it until it causes a problem. In other words don’t feel down on yourself about it. That is don’t feel like you have to ‘clean up your act’. That isn’t to say that you shouldn’t keep things as organised as possible but really organising is not a black and white thing.

    As for the incident itself. Of course mobile phones (and other devices and other things) can disturb much more than just ECGs in medical environments. Metal/jewellery/etc. is a good example of problem objects. And although maybe they (mobile phones etc.) shouldn’t be in a laboratory sometimes – well there are times where one might have to. Whether that is something that can be changed is another matter entirely – but would depend on each circumstance. One might argue that years ago (though I know many many people are too young to remember this …) they managed fine and that’s true. But it’s not easy to fairly or accurately compare a different time to the present time. It’s riddled with problems. This goes for judging people and their actions too.

    As for the problem that the phone caused – as in where the problem showed itself – I find it really interesting and much more than that; it’s extremely fascinating. It’s a great example of how the impossible can become possible. It’s also a great example that no matter how experienced you are there are always things you will not foresee. It might or might not surprise you but that probably depends on what you’re surprised about; if you didn’t think of it and it happens that doesn’t necessarily mean you’re surprised once you see it happen. Rather it means you didn’t think of it. There is a difference though it might be too subtle for some people. Thanks for sharing the story. It doesn’t apply to me but the idea is fascinating.

    Debugging is not a science as I have learnt over the years. It’s an art and once you get really good at it if you look back at how far you’ve come it’s an amazing experience. I remember when I first started and what I am capable of today and how I work problems out (seeing things I would have never before, thinking of it without much effort, even expecting it and being very often correct).. It’s an amazing difference. I personally find things like what you described the most enjoyable type of problem solving. More specifically it’s the most fascinating and you learn new things that will help you in the future. As you have discovered in fact!

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