Money Lost

T-Money, that is. I wrote about this special device that is used for subway and bus fares (some taxi's reportely will accept it, too) back two years ago. Well, yesterday this two-year old widget (it attaches to your cell phone) broke. It wasn't visibly broken, it just refused to work. I took it to the station clerk, and he tried it on his machines, and confirmed that it was dead.

You know what's coming... Engineer, broken electronics item... You guessed it. I dismantled the thing to see what's inside.



Here is the main brain. Attached to a wire loop antenna and what I'm guessing is an inductor used for impedance matching.



The cool thing is that I could see immediately what was wrong. One of the antenna wires had come unsoldered. I think I know why it broke, too. You'll notice there is a small pocket in the body of the plastic case, which is where the electronics should be located. In fact, it looks like there was some adhesive holding it down. I say was, because when I opened up this unit, the whole thing was rotated slightly, so that the electronics was at the edge, or slightly outside of that pocket. I believe the resulting stress broke off the antenna wire. I simply soldered it back, and hopefully it will work and I won't lose the $6 or so remaining value.


I'll test it tonight and report back.

EDIT: It works! All those years of Engineering school finally paid off!