NEC has a fairly awesome FAQ about FET circuits. Simple enough for the beginner, but detailed enough for people interested in the nitty gritty details.

I think I've said enough here.

While we're on the topic of painting, I have to show off KIP's spectacular Katamari Damacy Russian Dolls:


Amazing!

I like to buy paintings and prints from the thrift store and supplement them with my own artwork. Usually it's really crappy and I just have to throw out the results because I wouldn't be caught dead with them hanging in my home. With a topic as wholly righteous as DUCK HUNT however, how can I possibly go wrong?

Click for larger images.

Dwayne and I were just having a discussion about soil pH, which reminded me of some experiments we did in my middle school science class. You can make a neat-o pH indicator by brewing a sort of tea with the head of the Red Cabbage. It can be used in it's liquid form by titrating with your analyte (perhaps water in which you've steeped some soil from your garden) or by soaking filter paper in the solution and allowing it to dry, forming your own homemade pH paper. Here is a link with a HOWTO for distilling your own red cabbage juice.

Well, it's garden season again, which means it's time to start composting. I meant to be composting throughout the winter, but a telephone pole fell on my old compost pile, and I've had absolutely no motivation to repair it. It wasn't much of a pile anyways. As anyone who knows how it works will tell you (not me!) composting can be tricky. It takes a delicate balance of nitrogen, carbon, moisture and air to do it correctly, and if you're doing the conventional compost "heap," that means making sure your balance of raw material is good, that the heap is well drained, and that you turn it over quite regularly so that air can get to the microbes that need it.

Some folks (especially urbanites like myself) have resorted to compost tumblers, which alleviate the air and moisture issue by making it easy to aerate and drain the pile. These tumblers are cool, but often expensive. Since it's essentially just a drum on a fixed axle with some holes poked in it, it was fairly easy to build one myself on the cheap. I settled on a design that maximizes air and drainage, keeping the compost moist but not wet, and aerated but not dry. I did it for about forty bucks, and it didn't really take any special tools. Enough! On to the pictures:

First off, grab an ordinary refuse bin:

I use this "animal stopper" bin, which has neat little straps to hold the lid on. This is helpful when it comes time to tumble the mess.

I drilled a hole in the bottom, and fit a pipe in there. It's 1/2" ABS drain pipe with a threaded fitting. The fittings are all solvent welded with acetone. This pipe will run up the inside of the drum, branching periodically to deliver air to the compost. Here's the first of 4 branching posts I run up the middle.

I put in four of these posts. They deliver air to the compost, and form structure inside the drum over which it tumbles.

The pipes are held in place with tee fittings, and connect with the outside of the drum using the same threaded fixture that connects it to the bottom. Here's what it looks like assembled loosely as a fit check.

Of course this is a tumbler, so it needs an axis around which to spin. I drilled two holes on either side of the drum, about half way up. I fortified the holes with a threaded PVC fitting and run a half inch pipe through them. This provides a rigid axle around which the tumbler can spin

The white fittings are the ones for the axle. I've also put the first aerator in the bottom. Just like the fit-check, except I've actually drilled the air holes, solvent welded the fittings in, and made everything pretty.

Let's take pause here, before assembling the whole aerator. The ABS pipes bring air in, but I wanted a drain to bring water out, as good drainage is key to good composting. I upended the barrel, and cut some drain holes, like so:

I did this, and actually all the holes for the 1 1/2" pipe using my trusty jigsaw.

To prevent my compost from spilling out into the yard, I cut up some old milk crates to form grates for the drain holes on the bottom. Again, using my trusty jigsaw:

Find these behind your local gas station, kids!

Here's both the grates in place, affixed with wire ties:

Clearly, I was more organized when I did the second grate. The first side was kind of haphazard.

And the inside of the bin, with the axle stuck through it:

Almost there!

Ta-da! I had my roommate Taylor drive some 2x4s into the ground, and I punched a hole in each for the axle. I hang the tumbler on it, and give it a quick spin every time I throw something new in it.

Fuzzy photo, sorry.

Here's what it looks like on the inside:

Compost.

That's all for today everyone!

As I renew the domain name for gogglemarks.net, I think to myself; "Hey! I should post to my site more than once a month!" Maybe people are interested in the inane stuff I'm doing in my home shop, so I'm posting that. If you don't like it, oh well.

I was inspired by a post I saw somewhere to build my own guitar. I can't play the guitar, I don't own a guitar, but I'm somehow compelled to make one, and that compulsion won't go away until I build at least one crappy guitar.

My roommate Taylor has a guitar, fortunately, which he let me borrow to try out my pickups and amp and stuff. I'm making an electric guitar.

Here's the circuit:

Obviously it's a little fuzzy. I was too lazy to do math. I pulled out an old board from a CRT monitor and just started pulling junk off it until I had a passable amplifier. I got the piezo element from an alarm clock. I got the speaker from... some old thing with a speaker. I dunno. It was in a pile. The only "new" part was an LM324 from a big crate of LM324s. I use it because it's cheap, not because it's an awesome op-amp (it's not)

Here's a video of me shredding:

Taylor had this epic pile of gross, leftover Christmas cookies and candies from his work. Most of it went straight for the trash, but there were a ton of these little santa chocolates that were baked into right into cookie cutters. I harvested the cutters and started mangling them with tinsnips and pliers, retooling them into my own diabolical shapes. Choice of shapes was easy... See the photoset here.

If you use Microsoft Word a lot, you probably already know this technique, especially if you use it to write a lot of technical material. You can "trick" it into replacing certain character sequences with special symbols using the AutoCorrect feature. This short-cuts around the fairly tedious Insert->Symbol process that we technical writers have all come to loathe. (Link via The Embedded Muse)

Right on the heels of my previous post, HOWTO Repair a Guitar Hero Controller Whammy Bar, I've got another one for all you Guitar Hero fans. The technology I describe here is one for your guitar-type controller that allows you to amass star power. Hoarding it in effect, as though it was a precious delicious nut, felled before the coldest of winters. it has been dubbed by my friends: The Auto Whammy. It took less than two hours to design and build, and is an extremely simple, cheap and fun mod.