Thursday, October 23, 2008

why was this not made

I know the answer to that question, but damn.... I want this. "Quickly children - Bor-El's minions have found us! Into the RV-2, quickly! RV-2, retract camper and prepare for escape!!"

Toyota RV

Sunday, September 28, 2008


I've never really had a car to work on before.  Our 2 Hondas are serviced by the Honda guy, I never touched my Ranger or Chrysler, not even an oil change.  With the Z car, I decided that I was not going to take it to anyone unless it was an emergency, and get as much practical knowledge as possible.  

I have the brake pads to do a brake job, but I decided to get a little more work time in before I tackled that.  I bought the Haynes manual, which tells you how to do everything up to and including rebuilding the transmission.    

So far I've - 
 - put a vacuum-molded dash cap on the dash, which covers up the cracks quite nicely and looks just like the original dash
 - added black leather seat covers and steering wheel cover.
 - removed the spare tire,  non-functioning a/c system, cruise control, and weird injector cooling fan.  This amounted to over 100 pounds of weight, which isn't really noticeable performance wise, but the engine is a lot more accessible without all that crap glommed on to it.  I also took out the perfectly serviceable air filter and put a ricer boy cone filter on, just for kicks.  

The spare tire was a brilliant design which was stored flat, and came with the (original!) can of compressed air.  You were supposed to inflate the flat spare tire, and then deflate it when you were done and put it back (and buy a new can of compressed air).  I replaced it with a can of fix-a-flat.  

Then I changed the oil, for the first time ever, and the fuel filter.  Lessons - the oil doesn't land where you put the oil pan on the ground, and change the fuel filter outside, because the garage smells like gas a lot now.    

So now it's all set up - next, changing the transmission and differential oil, then that brake job...

Saturday, August 30, 2008

Midlife crisis, 6 years early

I've been hankering for an impractical, temperamental, gas-swilling weekend conveyance for a while now. Dad and I went and looked at a pristine El Camino last weekend - well, it turns out that my cherished memories of the El Camino are best left as that. Completely out of the blue, because they fell into my narrow craigslist price range search, I became interested in old Datsun Z cars.

And today, I bought one. I think it frikkin' rules. It rattles, squeaks and only ventilates you when it feels like it. But just LOOK at it. T-tops, 6 spoke wheels and Ferrari red. And the interior is even decent. And it's got a great inline-6 tractor sound.

Plus, you owe it to yourself to check out the youtube ads. The 280ZX had one of the finest ad campaigns I've ever seen. Steve Wozniak and BLACK GOLD.

Monday, August 18, 2008

Yet More Speakers!

I finally bought a router and built some nicer looking speakers. I don't know what took me so long to learn how to use a router, they add a nice finishing touch. These are made out of solid oak project boards from Home Depot, rounded the edges over and flush-mounted the drivers (Jordan JX92S full-range). They are the MLTL 48 transmission line design, although the cross-sectional area is a little too small.

Sound great, though, much more bass than the previous set of speakers, and they can be driven at more realistic volume levels.
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Thursday, July 17, 2008

Crates make good houses

We got a new instrument for the lab a few weeks ago. (a Corning high-throughput label-free screening platform based on optical biosensor technology).

It came in 3 huge crates, and another crate that contained a small forklift for use in assembly. I'm not kidding, it shipped with its own forklift. Curiously, the guys that assembled the thing never even uncrated the forklift. Which is too bad, because me and the delivery guy (who looked, dressed and sounded exactly like Larry the Cable Guy), took a huge amount of time and sweat to git-r-done and move that sucker off the truck, on to the elevator, and into position.

But I digress. After uncrating the instrument, the crates were left behind. And they were pretty neat. Made of OSB (oriented strand board) and disassemblable into their component parts via a clip mechanism, they were a production in themselves. Apparently they have a whole warehouse full of the empties (I guess $250,000 scientific instruments are hot these days), so they asked if we could use them.

I just can't resist the call of free crap, so I said sure. I spent 2 hours one Sunday taking the things apart, removing the extraneous packaging (one of them had a complete sled with shockmounts, made of 7/8 inch 9 ply plywood), humping them down the hall to the elevator, moving them out to the illegally parked minivan, and getting them home.

Yesterday I finally got the chance to take them out from under the tarp and prepare them for their new role as a playhouse. I'm going to stain them grey and add some mid-century modern overhangs, but they're a success already, although of course the big kid prefers playing on the top to actually playing inside...

Friday, June 27, 2008

Speakers, more or less finished.

Here they are. Lots o' changes. I cut the line length down to match the measured (as opposed to published) driver specs, added a wing to counter baffle step loss, and tweaked them no end with various damping materials. But it worked out, they sound wicked awesome now.

Monday, May 19, 2008

speaker of the house

Every couple of years I get the urge to build a set of speakers. In California I attempted to build a copy of the famed Gallo Nucleus speaker. I did get the same bass drivers, but I used 2 plastic bowls instead of the recommended stainless steel spheres, and used some ribbon tweeters from Electron Hut instead of the handmade cylindrical driver. Needless to say, no one was worried about copyright infringement.

Then 2 years ago I built a couple of garage speakers based on plans from Parts Express. They work just great out in the garage, but I was getting itchy to build something better for the living room. This time around I thought I would head into the world of full-range drivers. Full range is kind of a step backwards - instead of having a separate woofer, midrange and tweeter to handle the audio spectrum, full range attempts to get all 3 out of a single driver. The idea is that by avoiding a crossover point between drivers, you get a more natural sound.

Needless to say, this poses problems. A big cone can't really move fast enough to reproduce high frequencies accurately, so you either have to stick to drivers 4" and under, or put a "whizzer" cone onto a larger driver, which kind of makes the highs shouty and directional. But, how much bass can you get out of a 4 inch driver, a stiff 4 inch driver at that? As it turns out, a surprising amount.

The driver I'm using is the Fostex FE126E. As with all things obscure and inscrutable, it hails from Japan. It's a 4 inch diameter driver with a cone made of banana pulp fiber. Its Xmax (how much the cone can move back and forth) is an amazingly small 0.3 mm. Picture a boom-boom subwoofer pumping air, and this is the exact opposite. It has a magnet nearly as large as the cone itself, which means it's a very tightly controlled driver - when it's time to move, the cone is going to move, with almost no slop.

So where does the bass come from? There are a few options, all of which revolve around horns or resonators. When you put your hands up to your mouth and shout, you are forming a horn. Your voice becomes louder in the direction you point your hands - you are sacrificing coverage for intensity in a specific area. When you put your mouth at the end of a paper towel tube and speak into it, that's more of a resonance effect - the tube is amplifying certain frequencies due to its resonating like an organ pipe.

So, by having the back of the speaker fire into an appropriately shaped chamber, we can exploit the resonance and horn effects to effectively amplify and direct the tiny bass output of the driver into usable bass that should mesh with the mid and high frequencies coming from the front of the driver.

After looking at several options, I chose the BIB design, or "bigger is better". This design is brilliantly simple, involving a box with no top and a single internal piece. This forms a folded horn/resonator. The driver is mounted in the skinny end pointed forward, and the horn ends up firing up. The speaker is placed against a wall to further reinforce the bass frequencies.

I've already prototyped a pair in cheap plywood, and now am building the real thing. A side effect of the horn pointing up is that it disperses the bass and midbass vertically, giving a very open, natural sound. The bass is ample, to the point where you're looking for a hidden subwoofer.

Wow, can I go on about speakers or what...

Friday, April 18, 2008

The Speed of Sound

Most instrumental guitar albums from the 80s are pretty much unlistenable now. Most of them were pretty unlistenable then, even if you were high on testosterone and Stridex acne pads.

I'd make the case for Ronnie Montrose's Speed of Sound as one of the few exceptions to that rule. I loved this album then, and it holds up today. Who the hell is this guy? Well, apparently he played with the Edgar Winter group (don't know if he did Free Ride or not), and had his own band (fronted by... echh... Sammy Hagar), but he is primarily known as an instrumental guitarist.

The album is from 1988 and features drum programming from the era where "the drum samples are good, but the dynamics aren't there", and mostly electronic, sparse accompaniment. The guitar sound is Heavily Processed, from an age where guitarists had eschewed the pedals-into-amp approach in favor of the rackmount Guitar Processor, lending the tone copious amounts of reverb and distortion that actually did not model any kind of amplifier or pedal, but was its own entity. It's a warm, fuzzy sound that in this case, doesn't sound "loud". You can put this album on and not want to put blankets over the speakers.

The playing is restrained and tasteful (as it gets for the genre). Very few wheedlie-whees, mostly simple melody lines and embellishments, with a good bit of emotion. I remember reading an interview with him in Guitar Player where he said his hand was healing from slicing it open with a knife, so recording the leads involved a significant amount of pain, which might explain the lack of pyrotechnics and the emotion-charged bends.

All of the songs have spacey names like "Outer Marker Inbound", "VTOL", and "Zero G". There's even a cover of the Ventures' "Telstar". Here's a sample from Amazon.

As with any album that was part of the soundtrack to your youth, I've lost all ability to judge it objectively. The songs put me back, waiting in front of the hardware store in the winter for my dad to pick me up from work. I'm listening to it on my new Toshiba walkman with auto-reverse and built in 3-band EQ. It's dark and snowing a little, and the guitar sounds perfect.

Thursday, April 17, 2008

Computer Dashboard, part 8 - All Done

Back to part 7

Well, here it is in its final form. I used Visio to print out a faceplate for it, and created some scales for the meters. Originally I was going to make a weather module that would scrape and return weather information to be displayed, but never got around to it.

I've had it hooked up to any number of computers since building it in 2005. It's currently working right now on my work computer. Only problem is that it doesn't move that much because I have such a beast of a machine that it's hard to tax it enough to push the CPU, Memory or Disk readings up. The Memory and Disk meters read pages/second, so they're not just measuring how much memory is being used in total, but the accesses.

It does impress people, though. You can send yourself an email and watch the email light glow, then read the email and watch the light go off. It was a fun project, and I sort of had plans to build quite simplified versions (say, a bobble head that starts going when you get new email or something equally insipid), but the cost of the USB I/O boards is somewhat prohibitive. And then I got interested in something else.

Wednesday, April 16, 2008

Computer Dashboard, part 7 - Software

Back to Part 6

The journey is almost complete. Just one last link in the chain. We've covered everything that happens after the signal leaves the computer via the USB cable, but how do we send the appropriate information to the USB board?

The USB board comes with a software component that lets you set the values of the pins via any number of programming languages. I chose C# because I had Visual Studio and the component was compatible. Comprende? I wrote a little C# program that queries the Microsoft system software many times a second as to the status of the CPU, the memory usage, disk usage, and network usage, and also whether there are any new emails. Here's a code snippet:

// setup of adapters and monitors
currAdapter = "CPUPercentageAdapter";
currMonitor = "CPUMonitor";
((Adapter)adapters[currAdapter]).Device = meters[0];
currAdapter = "CPUYellowAdapter";
((BinaryAdapter)adapters[currAdapter]).OnAt = 50;
((BinaryAdapter)adapters[currAdapter]).OffAt = 85;
((Adapter)adapters[currAdapter]).Device = yellowlights[0];
currAdapter = "CPURedAdapter";
((BinaryAdapter)adapters[currAdapter]).OnAt = 75;
((BinaryAdapter)adapters[currAdapter]).OffAt = 110;
((Adapter)adapters[currAdapter]).Device = redlights[0];

I structured the software around an Adapter and Subscriber model - an Adapter talks to one of the devices on the dashboard, and it can Subscribe to a Monitor. So if the CPU meter Adapter subscribes to the CPU Monitor, it will show the current CPU status. You can see in that code that I'm also setting some threshold values, so the CPU yellow light comes on at 50% usage, and the red light comes on at 75% usage.

All the gucky bits where you actually play with bits and do math and stuff are tucked away in the Adapter and USBDevice classes, so at the top level, you just hook up an Adapter to a Device, and Subscribe to a Monitor, and it magically shows up on the dashboard. The picture shows all the components in the chain.

Tuesday, April 15, 2008

Computer Dashboard, part 6 - Multiplexing

back to Part 5

I bought 4 meters and 4 LEDs and a box and came up with a layout. I figured that would be a good number of things to measure. Problem was, I didn't have enough pins on the I/O board. Each meter would need 5 pins dedicated to it, and each LED would need one, for a total of 24 pins. I only had 16 pins.

I thought about this for a while with no good ideas, and then, as is it so often does, a model railroading site came to the rescue. It seems to be dead now, but here's a cached copy. They had the same problem of wanting to control a bunch of stuff from a parallel port, with not enough pins, so they designed a parallel port expander using a gizmo called an octal latch.

An octal latch is kind of like a very small memory chip. It's called octal because it can store up to 8 bits of data. The way it works is, you signal the chip and say, "hey, I've got some data for you - here's 8 bits." The latch takes those 8 bits and outputs those 8 bits until you come back with some more data for it, at which point it forgets the previous 8 bits and starts outputting the new 8 bits.

So how does this help? Well, if we give each meter one of these latches, then we can run from latch to latch, setting values for each meter. In effect, we can use the same 5 pins on the I/O board to set each meter - we just activate one of the latches, send our 5 bits, the 5 bits get converted to a current, the meter displays that current. The 5 bits are held for that meter until we come back around to that meter and give it a new value.

Because we can cycle around many times a second, all of the meters appear to be moving simultaneously and independently, when in fact they are being set separately, one right after another. So now we can use 13 pins to set all of our meters and LEDs:

1 - activate latch 1
2 - activate latch 2
3 - activate latch 3
4 - activate latch 4
5 - 9 - 5 bits of meter output
10 - 13 - 4 LED outputs

Whew. Well, that covers all the "hardware" stuff. The latches, R/C networks and resistor networks were all placed on one breadboard, with a LOT of soldering. Because I hated to waste 3 bits on each latch, I decided to add a red and a yellow LED inside each meter to indicate some condition (medium value or high value), and piggybacked those onto each latch - so I actually ended up using 7 bits for each meter, 5 for the value and 2 for the LEDs. I put the LEDs inside the meter cases, and they glow from behind the meter scale.

Monday, April 14, 2008

Computer Dashboard, part 5 - Dampers

Back to Part 4

In the previous chapters we've seen how output from the pins of the I/O board can either switch an LED on or off, or move a meter. After doing some tests, I noticed that while it worked just fine, the output was rather "harsh". The LED was ON or it was OFF - immediately. The meter snapped with precision and speed to each position on the scale. Now, this might have been cool in the early 80s, when digital was new. But nowadays it's hip to soften the edges a bit and "fake" analog.

Witness the hypnotic sleep indicator on a MacBook - it fades in and out, as an incandescent lightbulb might do. So what I wanted to do was add some smoothing to my output devices - something to make the meter gradually move from one position to another, and fade the LEDs in and out.

This is very simple to do with a simple R/C network in between the output pins and the device. An R/C network is simply a single resistor and capacitor. A capacitor is like a very fast charging battery. (well, not really, but think of it that way). A resistor will affect how fast the capacitor charges. What this means is, when an output pin turns on, you can wire the resistor and capacitor in such a way that initially, most of the current goes into charging the capacitor, rather than into the LED. As the capacitor charges to full, more and more of the current goes into the LED. This results in a slow-on effect. When the pin turns off, the full capacitor discharges through the LED, resulting in a slow-off effect. Same for the meter - the capacitor will soak up current and release it during any change, resulting in a damping or slowing of any movement. The picture shows this - the input signal is the square spiky thing, the output is the gentle rampy thing.

I had to fool around with the resistor and capacitor values to arrive at the final configuration, but it's quite effective. Nowadays they're showing kids how to arrive at the same effect by programming microcontrollers. Sigh.

Friday, April 11, 2008

Computer Dashboard, part 4 - D/A Conversion 2

Back to Part 3

Gee, this is getting a little epic. Keath, I'm glad you're enjoying it. Or at least reading it. So. We have a meter to swing, and a number of pins, each of which can output a set voltage. What we need to do is some binary math. For my purposes, I decided that my meters were small enough that setting them to one of 32 values was going to be enough precision. That meant I needed 5 pins to dedicate to a meter, because 2 to the 5th is 32. Got it?

No? Well, binary numbers represent numbers with just 2 values, 0 and 1. Just like in decimal numbers we have the "ones place" and the "tens place" and the "hundreds place", ie, 124 has 1 in the hundreds, 2 in the tens and 4 in the ones, binary numbers have the 1's place, the 2's place, the 4's place, the 8's place, and the 16's place, etc. So, if you are using 5 pins, you can count from 0 to 31, because 16 + 8 + 4 + 2 + 1 = 31. That gives me 32 values, so for instance, the number 10011 is 16 + 2 + 1 = 19. (n-n-n-nineteen).

Got it? Well, go google it or something. The point, is we need some way of making pin 5 "count" more than pin 1. When pin 1 changes, we only want the meter to move by 1 unit. When pin 5 changes, we want the meter to move by 16 units. The way to do this is with a resistor ladder. As shown in the picture, each of the 5 pins will connect to the network from the bottom, and there is one output, to the meter. Pin 1 will be connected furthest from the output (marked LSB on the diagram), so as the voltage from that pin makes its way across all of those resistors, it will be dropped until it contributes very little to the total at the end. Pin 5 will be connected nearest to the output (marked MSB on the diagram), so the voltage from Pin 5 only has 1 resistor in its path to the output, and will thus influence the voltage, or current, at the end, much more. (Resistors drop voltage, by the way).

That's it - that's how simple a digital-analog converter can be - a bunch of resistors. Going the other way - not so easy.

Thursday, April 10, 2008

Pollen Nation

It's pollen season here in the south, and here in the south, pollen is not just an abstract thing that floats around and makes allergy sufferers complain. Oh no, it's a fine yellow dust that coats, I say coats, everything. These pictures really don't show you the full scope of the coverage.

On the doorstep one you can kind of see footprints, and get an idea of what color the doorstep is supposed to be.

I'll have to upload another picture when it rains, when the streams and rivulets run bright yellow with plant spooge.

Wednesday, April 09, 2008


I am a huge Anglophile, so this storyline in Achewood is making me larf und larf. Keep clicking next, it's ongoing, and is still in progress.

The Shrovis-Bishopthorpe Envaliant III

Tuesday, April 08, 2008

Computer Dashboard, part 3 - D/A Conversion 1

back to Part 2

Meters work by swinging a needle in response to an electrical current. No matter what the scale on the meter says, "Degrees C", "Fuel Level", "Houseguests Offended", the meter only cares about one thing- when you feed it no current, the meter goes to (usually) the left, or Empty, or 0, and when you feed it the maximum amount of current, the meter goes to Full, or 100, or "That's a paddlin'", or whatever. So the meter needs to be fed a variable amount of current, in response to whatever you're measuring.

Now the ActiveWire USB board doesn't have the ability to output a variable amount of current. It has 16 pins, each of which can either output a voltage (5V, I think), or no voltage. So somehow, we need to take a number of those pins, and change various digital combinations of "off" or "on" into analog values, varying between 0 (no current) and 1 (the maximum amount of current).

Such a thing is called a digital-to-analog converter, and it's amazingly simple. This is the same way your CD player or mp3 player works (more or less). What happens is that you assign a number of pins to represent a voltage (which is then converted to current). The more pins you assign, the more precisely you can specify the voltage. Let's say you assign 1 pin:

1 pin
On or Off
Analog Values:
0 or 1

2 pins
Pin1 ON, Pin2 ON
Pin1 ON, Pin2 OFF
Pin1 OFF, Pin2 ON
Pin1 OFF, Pin2 OFF
Analog Values:
0, 0.33, 0.66, 1

The more pins you assign, the more precision you get in the analog signal. CDs use 16 "pins", or bits, and all they do is read 16-bit sequences from the disk, many times a second, and simply send that voltage level, or current, to the speakers, which results in a waveform, which is converted to sound.

Sunday, April 06, 2008

All paneled in

The ice fishing hut is all paneled in. Here are some pics from the outside looking in and the inside looking out. Still needs some backwoods pimpin', but it's nice to have a dust-free space to solder and do endless metronome exercises in. I also had to put my shop back in order as a side effect, so now I have no excuse to not get to all that stuff I said I'd be getting to...

Thursday, April 03, 2008

Computer Dashboard, part 2 - USB

back to Part 1

So, now that I had the meters and blinkenlights which would form the display, it was time to think about how the information was going to get from the computer to the display. I decided to start with the simplest case - how would I turn an LED on and off? To turn an LED on, you need a source of voltage.

The parallel or printer port used to be the tool of choice for doing this. You get multiple pins, each of which can be assigned to be either on (voltage) or off (no voltage), and there are multiple drivers which can help you set these pins from your software. However, the parallel port and its cousin, the serial port, are rapidly disappearing, replaced by the USB port.

As I found out, USB communication is not accomplished with a chip or two from Radio Shack. You actually need a license, which you must buy, in order to talk to the port, and talking to the port more or less requires a microcontroller on the other end. So it didn't look as though I was going to build one from scratch.

Fortunately, several companies sell boards that will plug into a USB port, and offer that same, tinkerer-friendly set of pins which can be assigned to on or off. The one I chose was from ActiveWire.

Once I got the board, I plugged it in, wired up an LED to one of the pins, and used the sample application that came with the board to turn the LED on and off. Success! Now I would have to figure out how to control multiple LEDs, and some way of controlling the meters.

Wednesday, April 02, 2008

Computer Dashboard, part 1

This is a project I built some time ago, but I thought I'd give it a write-up, since it's kind of interesting and maybe someone else will get some ideas.

The idea is to create an "ambient device", which is something that either connects to your computer, or to a network, and displays some kind of information in a way that doesn't involve your computer screen. For instance, Ambient Devices sells plastic orbs that light up blue or red, depending on weather forecasts or the stock market. Kind of a way to see information from the internets that isn't as useful or dynamic as having a computer, but looks cooler. Or different.

I wanted to build a device with panel meters (the things with needles that swing back and forth) to display information either from the internet or about my computer (like a car dashboard for your system - CPU utilization, disk utilization, network traffic).

I started, as I usually do, with the fun cosmetic junk - what kind of old meters could I find to go on the front. I went to my favorite store, Austin Electronics, to peruse their surplus meters, and found some edge meters that met my main criteria of "cheap". The big ones were surprisingly expensive. I also found some huge LEDs which I thought would make good binary status indicators ("do I have any new email?")

Monday, March 17, 2008

Cue up Fanfare for the Common Man...

... and feast your eyes on this. Late 2009. I will have one. That's no empty threat. I don't care what kind of gas mileage it gets, how bad the interior is, or if I need to grow a mullet. This is Neo, the One, the second coming. The car that thinks it's a truck. The truck that thinks it's a car. Listen! Its name is whispered on the wind.... el camino....

Monday, February 25, 2008

Dobbertin Surface Orbiter

This is possibly the most perfect vehicle ever created. An amphibious RV constructed from an old milk tanker trailer. I just... want to park this in my driveway. And stare at it.


Saturday, February 23, 2008

From Here I Shall Compose My Manifesto

There comes a time in every man's life when he realizes that the house he provides for his family has, in fact, no room in it where he may keep jars of paint and X-acto knives lying around. Since this house doesn't have a basement, and the garage is just a little chilly/hot in the winter/summer, I used the existing shelves and hanging storage shelves in the garage and attached some studs to them. I bought some fine fake cherry paneling for the inside, and will insulate the walls.

This will give me a 9x9x7 cubish space in which to work on fiddly things, woodshed my guitar, and hang my fishing trophies. Since it's so small, I expect that a small heater and window a/c unit should keep it comfy all year round. I call it my ice fishing shack.

Wednesday, February 13, 2008

I'm not dead

I know it's been a hella long time since my last post. And I know that all of my faithful readership is wondering just what is going on. Well, it's winter, and that's usually when I do some kind of smaller crafty project, but this winter I've mostly been focusing on improving my guitar skills. But I did just start construction on a studio in the garage, and I have some ideas for gas-powered miniature carnival rides, so something more substantial should be coming soon. In the meantime, please enjoy this picture of Mia as "Last Child on Earth".