On Thu, Dec 27, 2007 at 09:34:37PM -0500, Nick Holland wrote: > I've got a little project I'm working on here. > It involves stuffing a computer in a donation box with a > money detector, so every time someone tosses money in the box, > it plays an MP3 file. > > However, this is the first time I've ever done an OpenBSD system > that wasn't going to be attached to some kind of network for > (hopefully) years at a time. In fact, hopefully, it will NEVER > be attached to a network. And, while I got a 1G CF device, I > could imagine doing something stupid and having it slowly fill > the CF media and six months from now getting a call saying, "It > died. Come fix it", and since it will be in another country and > probably a ten hour drive away, I'd like to avoid that. :) > Once this thing is deployed, I won't have access to it at all, > so I'll have no ability to spot a potential problem or fix it. > What have I forgotten? Is there anything else I can do to avoid > slapping my forehead and saying, "D'oh! Forgot to ..." before I > ship it out fully detached? The good news is I'm pretty sure > there is at least one OpenBSD developer near-by, but that's just > all the more reason to make sure I don't screw it up, I'll never > live it down. :)
I'd wire in a hardware-type heartbeat detector that will power-cycle the computer if it stops working. I'd have a door over the money slot powered by the computer so that it only accepts money when its working. You could have a "Please wait" light to be lit during the reboot. Or, you could just rewire an MP3 player to play a tune when it is powered on, then just hook the money-detector to the power switch. Money turns it on, a timer just longer than the tune turns it off. No computer needed (just a 556-dual-555 timer IC and some spare parts). What about a built-in modem set up to allow a login. Then if something _does_ go wrong, you can ask the user to provide a phone line to the box and you with the phone number. With this, you can fix or even upgrade the box over the phone. Add a hardware cycle-counter; if the heartbeat causes a reboot and the cycle counter doesn't get reset, it lights a "please call for service" light. Doug.
