Updated Already

Posted 2011.03.20 22.10 in Computers/Internet/Technology by Stephanie

I couldn’t leave it alone, of course. Had to take it apart again today and make an update.

That thing with the WizNet module hanging sometimes, I had applied a very makeshift fix to yesterday. See, the WizNet doesn’t have its own power-on reset, but it needs it. They suggest you use a digital pin from your uC but I was out of pins. So I used a 10uF capacitor, which was enough to ground the reset line on power-up or manual reboot.

The problem was, I had my WizNet reset tied to my Arduino / ATMega reset, and the capacitor meant I couldn’t update the programming. At least, not without temporarily removing that capacitor.

So it turned out, I did have a spare pin. I had been holding A3 in reserve. Just incase the temperature readings from the Chronodot remained inaccurate due to the heat from the WizNet, I was prepared to add a TMP-36 analog temperature sensor, and dangle that a few inches below the enclosure. Luckily, with the thermostat mounted vertically on the wall, and the Chronodot a good 1″ out with open air around it, the temperature readings are accurate.

So I pulled it open, removed the capacitor, and unhooked the WizNet reset line from the Arduino / ATMega reset line, and tied it instead to A3. A few quick changes to the software, and presto, no more hang-on-powerup and it can be reprogrammed without any soldering. Yay!

Also, I decided to go ahead and show off the guts. Why not? Just be warned, if you’re easily upset by ugly wiring hacks and poorly-planned soldering and random wires and tapes and dead-bug construction… well just don’t look.

And finally, here’s a link to the updated software. The zip file also contains a text file that outlines the pinout & functions for the ATMega chip, the WizNet module, and the function of the HVAC lines — or at least, how they function in my house.

So Many Eggs

Posted 2011.03.20 10.35 in Aquaria by Stephanie

How do they all fit in there? How does she have enough room for so many eggs inside her shell, without totally displacing her own body?

Snails: bigger on the inside than they are on the outside.