nuxx.net
Making, baking, and (un-)breaking things in Southeast Michigan.

Splitting Ground

September 17, 2007

Here’s a quick electronics question:

How can I couple two groundplanes together, but isolate noise between them?

The reason I ask is because I’ve got a really noisy USB connection coming from my work laptop, and while I can feed it’s data lines right into the DAC, the ground connection for it is the same as the one for the outputs. I’m trying to figure out how one can couple those two grounds together, but cut off noise between them.

Best I can tell that’s just done with a ferrite bead… Is that right?

electronicsmoved from livejournal

Sheepie Preview…

September 15, 2007

More photos coming later…

This is just a preview of the Heritage Harvest Festival in Dryden, MI.

Due to some confusion Danielle and I attended the festival today instead of with friends tomorrow, but that’s okay. It was really nifty. There was a good bit of farm equipment, sawmills, animals, steam-roasted corn on the cob, trails to wander on, and stuff like that.

Anyway, more later. For now you get a really cute, freshly shorn sheepie. (By a multi-generation shearer who seemed to really care for her animals and made things from their wool.)

moved from livejournaloutdoorstravel

rowla.nuxx.net Problems

September 14, 2007

Oh boy. I don’t need this now:

c0nsumer@rowla:~> dmesg
[...]
ad0: FAILURE - device detached
subdisk0: detached
ad0: detached
GEOM_MIRROR: Device hotbackup: provider ad0 disconnected.
c0nsumer@rowla:~>

No SMART warnings, nothing. On Sunday the disk reported a clean healthcheck with 17970 hours of power-on time. ad2 had 24195 hours reported in the same log file. I’d expect it to go soon, too.

Thankfully ad0 is one of the first two disks on a secondary pair of disks in the box which aren’t critical. I first copy backups to those disks then copy them from there down to my house each night. Having half of that mirror set gone isn’t horrible, but I’ll have to take care of it at some point.

Maybe I’ll just throw one of the 320GB disks I have here on there in its place and finally get around to moving all my backup drives here internally. Time to check prices on new disks at Newegg I guess.

UPDATE: For $120 I can get a 500GB Seagate which would go nicely in my Mac Pro as a backup volume. I could then use one of the 320GB disks it would be replacing it as the hot backup in rowla.nuxx.net. I’d then have a spare 320GB I could leave attached to the Mac Pro via the FW800 enclosure, turned off, as an offline backup of photos.

Or I can leave it and wait until the other half of the hotbackup mirror set (ad2) falls over. The replacement 500GB disk will probably be cheaper at that point and it’ll require no work to be done right now.

This will be decided tomorrow.

around the housecomputersmoved from livejournal

Alien DAC: Built

September 13, 2007

Assembled Alien DAC w/USB Power (Top)
(Click for more photos…)

I decided that I’m going to build another one of those Millett Hybrid Maxed headphone amplifiers, except this time I want to build one using a bit more specialized parts, stick it in a case with wooden end panels, and fit both a USB audio adapter and input switch in the housing. As you can see here, the two PCBs will easily fit in the case. (The Elna RFS / Silmic II capacitors can also be seen there.)

Today the Alien DAC kit arrived from Glass Jar Audio, so I set to work putting it together. It really wasn’t too difficult, most of the parts were either through-hole or 1206 / 0805 SMT. The SOT-8 voltage regulators were real easy to solder as well, and I had very little trouble with the SSOP28 PCM2702E. The board is reasonably well laid out, but there are a couple of things I would have changed. I’m really not sure what the designer was thinking (I think he wanted to save space / make things more compact), as hand-soldering SMT IC legs to ground without thermals is a huge pain in the ass. Regardless, it worked out.

Oh, and the bottom of the board can be seen here.

electronicsmaking thingsmoved from livejournal

Xbox 360 Chatpad Disassembly

September 10, 2007

Xbox 360 Chatpad LEDsLEDs in the Xbox 360 Chatpad
(Click for more Xbox 360 Chatpad disassembly photos (photo gallery retired)…)

While out at lunch today we swung by Best Buy where I was both was hassled by loss prevention†and where I acquired an Xbox 360 Messenger Kit. This small keyboard which snaps on to the bottom of the Xbox 360 controller (wired or wireless) is a pretty nice accessory and makes typing messages and filling out forms on the 360 far easier than using the on-screen keyboard.

After looking at it for a bit, I realized that the Chatpad has four data lines, leading me to wonder if it is really a USB device and if the controller contains a USB hub. So, what did I do when I got home? I tore apart my brand new Xbox 360 Chatpad (photo gallery retired).

All of the photos can be seen here (photo gallery retired), but the most notable ones are the ones which show its PIC16F883 microcontroller, the individual key LEDs for specialized keys, and plastic peg / inverted dome key design.

† When leaving the Loss Prevention asshat demanded to see our receipts, and after questioning him briefly as to why he needed to see it, I took it out just to be nice, when he grabbed it from my hand, thoroughly checked it over compared to what I was carrying, then explained to me how it’s something he “has” to do, and that he “doesn’t check all receipts”. When asked if he picks who to check, he answered affirmatively, and when I asked why I was singled out for a subjective check he just walked away.

I’m still not quite sure how to deal with it from here, but what I should have done was simply not show the receipt and walk out the door. I’m not sure why I didn’t… Probably because I was talking with my coworkers who were standing there as well, and I couldn’t have just walked out to my car.

I partially feel like an ass for not doing what is right, and partially for having to deal with a jackass LP tool at Best Buy.

acquired thingselectronicsmoved from livejournal

Fermenting Chilis?

September 9, 2007

Inspired by this article on lactic acid fermentation of chilis to make Hunan Salted Chilis I did something similar.

Instead of keeping the seeds and chopping up a single type of chili I instead took home-grown habaneros and some red globe chilis which Danielle brought to me and put them in a bunch of salt along with some garlic. I ended up removing the seeds from all the chilis, cutting the habanero flesh into thin strips, and the red chilis into thicker strips / chunks. The garlic was cut into ~5mm thick slices. This was all layered in the jar with salt, then more salt was added, it was stirred, then even more salt was added.

Hopefully it’ll come out good… It’s now sitting in the bottom of my pantry where it’ll stay for a couple of weeks before I’ll open it for a test. Right now there is a bit of liquid collecting in the bottom, which I can’t take as anything but a good sign.

I probably would have used more habaneros, but I was running out of not-partially-dried large size ones and my goggles were beginning to fog up. Despite wearing mostly sealed goggles, a respirator with VOC cartridges, and latex gloves I still eventually got tingly eyes and a runny nose. Whenever I walk through the kitchen it starts up again. I’m also afraid to touch my penis without even more hand washing.

Now I think I’ll go check what parts I already have for the second Millett Hybrid Maxed I want to build. Hopefully this next one will have a different output stage and a USB DAC built into the enclosure. Oh, and I’ll take out the trash.

foodmaking thingsmoved from livejournal

Poor Bunny. :(

September 9, 2007

There’s a reason this post doesn’t have the image(s) right at the top…

Earlier today Danielle noticed that there was a really small bunny in the grass about 15′ from my front porch. I happened to have my camera in my hand, so I walked up to it and grabbed a few pictures before it started hopping away. Once it made it over to the pavement I noticed that it was dragging one of its back legs, as if the leg were broken.

Noticing this I took another photo of it on the pavement showing the displaced leg, and we figured that the rabbit was hit by a lawn mower (the grass cutting people were here earlier).

Unfortunately, after we looked at the full resolution photos, in particular this one, we noticed that the bunny seems to be missing the front bottom half of its nose/mouth area. There isn’t much blood, but it’s still pretty bothersome.

It’s a cute bunny, just (unfortunately) really, really hurt. :( It ran off after I took the pictures, but I don’t think there would have been anything that really could have been done for it.

around the housemoved from livejournal