Reviving the blog; stray beams
I don’t know if anyone still reads this blog, and I don’t blame them, but I’ve wanted to start writing again for some time. I’ve tried to keep this blog technology/infosec oriented, but I may shift gears and add new content. I think it may need a redesign, too. And, of course, I have to come up with something to write about that’s at least somewhat worth reading. In keeping with the spirit of not making posts without real content, I wanted to share an interesting incident that occurred last week.
I got up one morning and noticed it was somewhat cold in my apartment. It’s been very cold here in Chicago, and when the temperatures are in the single digits, I start to feel it in my studio. Wanting to warm the place up a little bit, I turned on my space heater. It’s a small model, not meant for a large space, but it does its job. However, within a few minutes, I noticed it turned off, without the power indicator LED turning off. Then it turned back on. Then off. The cycle kept happening.
My little space heater has several safety sensors, designed to make sure it doesn’t set me on fire, and I thought that perhaps one of them was going bad. Ah, well, it wasn’t too cold, anyway. Later on, I turned on my TV. I hit the “Guide” button on my cable remote and it was barely working. Some numbers on the keypad would somewhat work, while others didn’t at all. I blamed that on batteries, but thought it was odd that it happened all of a sudden, and that some things worked better than others.
As I went to later turn the TV off, I noticed the power button on my remote was stuck. That happens every once in a while, and it’s usually just an annoynace, because the TV will randomly turn off. So I unstuck it and then it struck me. The remote was, basically, acting as a little IR jammer. We tend to think of IR as very low power and not capable of much, but it’s a technology that’s used all over the place. And here, it was doing two things. First of all, it was preventing my cable remote from working correctly, by interfering with that IR signal. Second of all, it was bouncing IR rays around. When a stray one would hit my space heater, it would turn off. The reason is that the sensor used to tell if something has fallen onto the heater is IR based, and so a stray ray was throwing it off. It wasn’t consistently hitting the sensor, so it would only turn off every once in a while.
And if you’ve made it this far in the post and are curious about IR/IrDA in general, you might want to check out Major Malfunction’s presentation on IrDA security.
Posted: January 29, 2009 @ 5:41pm under Personal.
Comments: 2