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5116  Forum 2005-2010 (read only) / Bar Sport / Re: Oscilloscope recommendations <= $300 USD  ? on: December 20, 2010, 09:48:08 pm
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Lastly, just fuel the flamewar, I am a proponent of digital scopes.

I've got a 100 MHz 2-channel Fluke Combiscope - how do your feel about those?

 smiley-wink

If you are willing to buy used, I would only buy it if it came from a reputable dealer, or I could test it myself. Get yourself a pair of 100 MHz probes, and if you are able to test it yourself, hook up to the test signal on the scope and run it thru the simple "paces"; check alignment, focus (see if you can adjust them), etc. Generally, if it passes the self-test good, its probably OK.

I've bought two used scopes this year; one was a Tek 2213 60 MHz scope (like retrolefty's) - I had to buy a new implosion shield from a guy in Czechoslovakia; it was fogged from some chemical spray - but other than that, perfect (he had it serviced and calibrated by Tek - gave me all the documentation for it, too). I bought it off a guy on Craigslist for $150.00. Later I picked up a rolling stand for it off a gal on the ElectroTech forums for $25.00.

A few months back I picked up the Fluke - its a combination analog and digital storage scope (hence the name "Combiscope"); it was calibrated as well. I picked it up at Apache Reclamation here in Phoenix; paid $200.00 for it.

Both are great scopes; I wouldn't jump into the first thing I saw, unless it was a great deal (both the Tek and Fluke I got were pretty good deals - though had I saved my money, I could've gotten a 50 MHz Rigol DSO or something).

 smiley
5117  Forum 2005-2010 (read only) / Bar Sport / Re: When you think about it? on: December 19, 2010, 08:32:45 pm
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hey i just threw it out there and got soem feed back now if you can give me resons why then ill listen you all your trolling.

One big reason: Harvard Architecture (which wouldn't be so bad if more RAM existed)

 smiley-wink
5118  Forum 2005-2010 (read only) / Bar Sport / Re: 5 X 20 LCD on: December 17, 2010, 05:05:06 pm
I've never seen a 5x20 character LCD (doesn't mean they don't exist). Your best bet might be to go with a KS0108 128x64 GLCD, which is common and comes in the blue/white look you are looking for. Plus there is already a library for it...
5119  Forum 2005-2010 (read only) / Bar Sport / Re: Print your own transistors at home on: December 16, 2010, 08:55:49 pm
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The glove he's wearing on page 31 is a good indication of how likely the average schmuck is going to be able to get the chemical he's holding.   Grin  (the phrase "not very" comes to mind)

I decided to do some checking (Google's wonderful) - on page 31, he is supposedly "mixing P3HT in Toluene" - according to page 9 of the same document, "P3HT" is "thiophene":

http://en.wikipedia.org/wiki/Thiophene

Its MSDS (http://www.mathesongas.com/pdfs/msds/MAT23380.pdf) really doesn't reveal it to be a very harmful chemical (in the short term), provided you take some precautions (gloves and other standard labwear). Some more googling, though, actually reveals that "P3HT" is "poly(3-hexylthiophene)".

Some more googling reveals you can buy it online here:

http://www.bldscience.com/ProductDetails.asp?ProductCode=AC367380050

5 grams for $85.00 USD (!). As far as I can tell, they'll sell to the general public, too (though I didn't go through the sign up process - some places won't sell certain chemicals to individuals, only institutions).

I imagine that the other components and such could probably be procured with some minor tenacity...

 smiley
5120  Forum 2005-2010 (read only) / Bar Sport / Re: Print your own transistors at home on: December 16, 2010, 12:44:47 pm
Yes it does look like quite a process, and something likely requiring some chemicals and such that you just can't pick up off the shelf easily (in fact - though I haven't looked - an individual may not be able to buy them easily or at all).

There also seems to be some steps left out (or at least not as well explained - what's that "spin the semiconductor" part?).

Finally - what are the specs on the resulting parts? It seems like this would be an interesting "science experiment"-type project for reprap builders, but looking at the pics, these transistors are very large, and take quite a number of steps to produce.

I don't see this as being something practical unless they are able to reduce the size by quite a large amount (and if the specs of the resulting parts are such that the device is useful); still, though - its pretty amazing they were able to do it in such a manner...

 smiley
5121  Forum 2005-2010 (read only) / Bar Sport / Re: What's On Your Christmas List? on: December 08, 2010, 11:38:34 am
My wife and I have found that for our sanity and pocketbook, not celebrating holidays works out best. We used to dread xmas especially; the shopping, the crowds, the lines, the searching, the thinking of what to get someone who already has "everything".

No more.

Instead, throughout the year, if we want something for ourselves, we buy it. If it is something really expensive (more than $100.00 or so), we discuss it, then buy it if it will work in our budget. Furthermore, quite often the stuff we buy is used - from Goodwill, Craigslist, etc; we stay away as much as possible from the "consumerist trappings" (not watching television helps in that regard).

Things are calmer, there is a ton of less stress, and there isn't a huge credit card bill waiting for us in January (heh - I haven't had a credit card bill in two years, actually). Seriously, the whole thing every year just feels like a coordinated scam (and guilt trip) to transfer money from your pockets into the pockets of the corporate world - all for items and things that most people got last year, or for "new toys" that will be lost and forgotten over the coming year.

I have to say, though, that I would love a Kinect for hacking, but $150.00 is a little much. I'm willing to wait. Maybe by June of next year, or later, the prices will have come down. Or, I can wait for the knockoffs for PCs and others to come out; I'm sure by this time next year, we might see PC web cameras with the functionality built-in selling for $39.99 or some cheap price. I don't need it now, I can wait - and if I wait long enough, it will land on the shelf at Goodwill for $25.00.

 smiley-razz
5122  Forum 2005-2010 (read only) / Bar Sport / Re: SSR on Ebay on: December 14, 2010, 08:39:49 pm
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Just got 36 25A solid state relays on ebay for $74. Great deal. Merry Christmas to me.  Now what to do with them?

Heh - I'm kinda in the same boat; a couple of weekends ago I went to a local hamfest and bought a large heatsink with 16 25A SSRs mounted on them (each with a varistor across the outputs) in a 4x4 pattern. Got it for $35.00; have no clue what I'll do with them (but I couldn't pass up the deal!)...

 ;D
5123  Forum 2005-2010 (read only) / Bar Sport / Re: TI is competing with the MCP430 LaunchPad on: August 19, 2010, 05:03:48 pm
I made a post to someplace/forum about the release of this thing (tooting the Arduino horn) - since then I get updates from the forum when someone makes a post on it.

So far, the responses have been pretty negative - non shipping, long waits, pricing on shipping being higher than the cost of the chips, etc...

Overall, I think TI tried to do something to move into the hobbyist market, and failed miserably at it...

Something these wannabe players need to take note of: You can't create a hobbyist market for a product; such a community just "happens", and nothing you can do will generally make one happen. Typically, it takes a third-party using parts from the first; TI should've just released the chip thru their normal distribution channels and/or other channels, and just let it be used for whatever it was to be used for. Maybe it would've taken off, maybe it would've flopped.

You didn't see Atmel pushing to create the "Arduino" community; it just happened. Same thing with the Microchip PIC - Parallax started the whole "Basic Stamp" thing; Microchip was just the manufacturer of the original chip (which had its hobbyist adherents long before Parallax came around; but it was arguably the Stamp that caused the real sensation).

I think TI tried to do something here, and didn't really understand the market, nor were they ready to really fufill such orders (which is a totally different beast from volume orders).

 smiley
5124  Forum 2005-2010 (read only) / Bar Sport / Re: Rovio WiFi Cam Bot on: December 13, 2010, 04:51:49 pm
Nice find, and I definitely believe the price (I've found Roombas at Goodwill for not much more, among other items)...

 smiley
5125  Forum 2005-2010 (read only) / Bar Sport / Re: Why oh why Arduino? on: December 14, 2010, 11:28:30 am
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why ask why

Drink Bud Dry?

/now that's dating me...

 ;D
5126  Forum 2005-2010 (read only) / Bar Sport / Re: Why oh why Arduino? on: December 14, 2010, 10:20:10 am
Because.
5127  Forum 2005-2010 (read only) / Bar Sport / Re: Your last free sample? on: December 10, 2010, 12:28:26 pm
The last time I did any "free samples", it was for some 8-bit ADC chips from National Semiconductor; back then I had to call them up (pre-public internet days); they sent me out a tube of 5 that I never used (I was going to make an audio digitizer for my Amiga 2000, and never got around to it - that's how long ago it was!).

It used to be on some vendors sites (maxim and microchip, especially) you could easily request a sample online, without too much hassle. Since then, things got abused by dorks who used it as a supply point (maybe even reselling them on ebay) without actually purchasing a quantity afterward. Things have been tightened down, since then.

I think its still possible, but you might want to call the places up instead (go old-skool), talk to a real human, explain your need - they may take pity on you. Another route might be to look into chinese suppliers for certain parts and/or components. A friend of mine who was working on my robot project with me a couple of years back scored us a donation of a 200 or so mW green laser pointer from some chinese supplier (this was pre-ban days) we planned to use for a LIDAR system (it still may get used!). You might try that route (I'm still not sure how he pulled it off).

 smiley-wink
5128  Forum 2005-2010 (read only) / Bar Sport / Re: I Need Aluminum Bars on: December 07, 2010, 01:24:18 pm
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Aluminum is common in this type of thing though; some of the biggest names in it use aluminum...

Aluminum is probably common because it is cheaper than copper, thus the markup turns a greater profit.  smiley-wink

There is one advantage over aluminum that copper has (though you would want to use copper lugs on the copper wires as well to realize it, or not use lugs at all): less resistance.

When you have a junction between aluminum and copper, the resistance is higher (especially if there is corrosion). If you have enough current running through these junctions, they can overheat, and cause a fire.

This probably isn't a big concern in car audio, except in extreme installs of high-power amps and such (and at that point, copper is cheap, I suppose), but in a house it is a big concern. Back in the 1960s and 1970s, houses were constructed which used aluminum wiring, because it was cheaper than copper. However, a lot of appliances (lighting fixtures and such) used copper wires. Twisting these wires together and attaching a wiring nut is the common method of connecting the wires mechanically. Similarly, these wires were also connected to the brass connections on the sides of wall outlets. These mechanical joints had a much higher resistance than if copper wiring was used. In normal usage, this wasn't an issue, but as the current needs went up, these joints could become very hot - hot enough to start a fire.

I live in such a neighborhood (on the west side of Phoenix); my own house, long before I bought it, actually caught fire in such a manner (and was rebuilt, with the wiring replaced with copper). These houses are all 30-40 years old now; generally, if you hear or see a fire in a house on the west side of Phoenix, generally it is likely to be due to this kind of electrical work. I can't really lay the blame solely on the builders; more often than not, there is also an element of the homeowner running at or beyond the capabilities of the circuit, and not understanding that in relationship to this kind of wiring; but using aluminum wiring doesn't help.

I also tend to wonder if we won't see something similar in the future, simply because copper has gotten very expensive compared to aluminum - I'm sure there are new homes and other buildings wired with aluminum, and people are likely no more informed than they were previously about the issue...
5129  Forum 2005-2010 (read only) / Bar Sport / Re: I Need Aluminum Bars on: December 06, 2010, 09:54:49 pm
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Well, I need electrical grade aluminum... I am making aluminum bus bars for car audio.

You might also go to Lowes/Home Depot and look in their electrical box section (where they keep breaker boxes) and see if they sell pre-drilled/tapped ground/neutral bus bars for breaker boxes. That might be the easiest and cheapest option.

If you go the route of buying bar stock to make your own bus bars, you might as well go with copper. The places I mentioned, plus most online metals distributors will have copper bar stock. It isn't as cheap as aluminum, but its a great conductor, or so I've heard. smiley-wink

Just make sure its in an enclosure or something to protect it from moisture and the environment, as it will corrode, of course.

 smiley
5130  Forum 2005-2010 (read only) / Bar Sport / Re: I Need Aluminum Bars on: December 04, 2010, 11:37:35 pm
Sorry, I was out all day - I just now saw this...

The best place to go for this is called Davis Salvage:

http://www.davissalvageaz.com/

They're located off of Washington...

The next best place (but they're "new" metal, so prices are higher) would be "Hot Metals" - IIRC, they are located off of Deer Valley Road, about 1-2 miles west of Cave Creek Road.

Unfortunately, both places aren't open on Sunday - but they are the rest of the week, I am pretty sure. Hope this helps...

 smiley
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