Last weekend, Sarah and I went to the Maker Faire again. I love how I don't even have to negotiate with Sarah to go, she loves it just for watching the Combot Cup, where the combat robots destroy each other spectacularly.
Ever since Jon Oxer gave his Hardware/Software Hacking: Joining the Real and the Virtualtalk at Google about, I got vaguely interested in electronics again. The Arduino board seemed like a pretty cool thing to hack on, and since it seemed like I'd need to get vaguely electronically savvy to do a thing or two for the dream home we want to build one day (which coincidentally seems to quite similar to what Jon's currently building), I figured I'd have to get my act together and learn the difference between an Ohm and an Amp.
The last time I dabbled in electronics was as a kit, with the ubiquitous Dick Smith Funway 1 kit.
I've been flicking through the Making Things Talk book, and reading the projects. The Arduino board seems really cool. The Processing/Wiring language seems fairly straightforward.
I'd decided that my "project" would be a water monitor for the cat water bowl. We have a dish with a little tank on it, not unlike the office water cooler, and it usually lasts about 7 days. We typically refill it on a Saturday as part of the weekend chores. Sometimes our schedule gets a bit disrupted (we go away, we have visitors) and we forget. Or worse, we're away, have a house sitter, and they completely forget to check it. It's only happened a couple of times, but we really don't want to neglect the cats.
So I thought a water sensor would be a perfect project. One of the projects in the book involves a Bluetooth modem, so I figured that as the MythTV box has a Bluetooth adapter, and would be within range of the water bowl, I could use it to monitor the water sensor (as well as stick a blinking light on it). The end goal is to have the house call us (via Asterisk and eSpeak) if the water bowl gets empty.
So I ordered a Bluetooth modem, the exact part number in the book, and it arrived on the weekend, and I got around to playing with it today.
To cut a long story short, I was messing around with it attached to a USB to TTL serial cable, and I was trying to get it to talk to my laptop, and instead of swapping the TX and RX lines, I swapped the VCC and ground lines, and well, I let the magic blue smoke out.
What I discovered, after the fact, was that the Bluetooth chipset had been changed since the book had been written, and so the commands for the chipset were different. So most of my second-guessing whether I had the TX and RX round right way was because of that.
So I'm miffed with myself for frying the thing within hours of getting my hands on it, and I'm miffed with the supplier for maintaining the same product ID for a product that has changed componentry.
Chalk that one up to experience...
To add insult to injury, Spark Fun is out of stock of the (cheaper) item that it turns out I want instead. I doubt I'll get my hands on it until after we get back from Zurich, so it'll be another three weeks before I can begin to make any progress. I guess I can try to prototype the water-sensing part with the board connected to my laptop with the USB cable in the meantime...