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Andrew Pollock


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Sunday, 11 May 2008

Unleashing the magic blue smoke

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.

So the Maker Store at the Faire had copies of Making Things Talk, bundled with an Arduino starter kit, so I lashed out on one of them, a BoArduino, and a little breadboard-based electronics 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...

[22:40] [tech] [permalink]

Weekend away with the neighbours

We've been blessed with really wonderful neighbours in our apartment building. We know four out of the seven households in our building really well.

A while ago, we thought it'd be cool to rent a house and have a weekend away together, so we booked it for this weekend, rented a house in Rio Monte on the Russian River, and hung out together for the weekend.

Eight adults, 3 kids, and we're all still talking to each other afterwards.

Trying to coordinate outings with 2 small kids nap schedules was tricky, so we only made it to the Korbel winery, but we picked up some cheap champagne (an I thought you could only call it champagne if it came from Champagne, France).

Sadly, because Gavin and Christina have a second son on the way, they've bought a house up in greater Sacramento, and are moving out next weekend. We'll miss having them and Aiden as next-door neighbours.

We've decided that we should make this an annual event, so there'll be an annual "building 4" reunion.

Photos from the weekend are here.

[22:04] [life] [permalink]