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5056  Forum 2005-2010 (read only) / Bar Sport / Re: Sparkfun overpriced on: July 11, 2010, 03:34:55 pm
My first (well, only) Arduino I own came from Sparkfun; I've also ordered other components from them as well. I've never had a problem, and their shipping was insanely quick - but it helps being only a state away!

Yes, they are hobbyists, but they obviously have some business savvy. According to their history, SparkFun was started because they were in college/university (MIT?) and needed parts for a project - a lot of parts. Nobody could source the parts, so they did it themselves, and a company was born to do the same (and more) for others.

Can you get their stuff cheaper elsewhere? Certainly. Are they perfect on their shipping and customer support? Not likely - who is? Will they bend over backwards to help you? Maybe - how nicely did you ask?

Honestly, for them to be doing as well as they are in this economy says something about them as a business; what exactly that is, I am not certain, but they are doing something right, I think.

Businesses don't exist to sell things to customers at the cheapest price - they exist to sell things to customers for what the customer will pay for it. Indeed, there have been businesses which didn't last long precisely because they under-priced their product. Yeah, I know that seems crazy, but we are talking about humans here, which isn't exactly the most rational species on the planet.

As with everything, you need to shop around, and make decisions based on price, shipping time, needs, reputation, customer service, quality of product, etc. For some things, for me, I would probably buy from SparkFun. For other items, I would go to other vendors - even Ebay vendors (I have a few on my list that I like). For still other items, especially if I need it quick, I will check local stores and surplus outlets.

Finally - sometimes "cheapest" isn't "better"; sure, you can get a cheap alternator from AutoZone with a lifetime full-replacement warantee; but you'll be taking that thing in and out of your car every six months - but it must be better because its cheaper, right? What's your time worth? For me, I'd rather spend the extra money at Napa.

 smiley
5057  Forum 2005-2010 (read only) / Bar Sport / Re: Three Servo Hexapod? on: January 15, 2011, 12:29:19 pm
I think he means "3 servos total" - for a recent one that was posted here on the forums (and very cute!):

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1294651977/14

 smiley
5058  Forum 2005-2010 (read only) / Bar Sport / Re: Stupid question? How do you keep your bits tidy? on: January 14, 2011, 11:49:36 am
I have a whole bunch of Stack-On brand multi-drawers in my shop to hold everything.

The question for you will be "will you be moving any time again after your move" - for me it was "no, not for more than 10-20 years", most likely; so the multi-drawer boxes made the most sense.

If you think you will be moving, or you want a more portable way to move your parts, think about something like fishing tackle boxes. They make several different kinds, many with clear inspection windows. Some are designed to be easily stacked. You might even be able to find some that can be stacked and used on a bench like regular multi-drawer boxes, but portable.

There's also specialized tool boxes and such with dividers and drawers and similar partitions available for electronics and regular hardware (go to your big box home depot type retailer and look), that might be able to be used - meant to carry parts like screws, nuts, bolts and such on job sites (home construction and such). They may or may not be more or less expensive than fishing tackle boxes.

But here's the key - whatever system you ultimately use:

1. Buy more of the boxes than you need (because, eventually, you'll need or want more).
2. Buy and use a label maker for labeling your parts bins.

The reason for number 1 (and this applies to any time you are buying storage containers of any sort) is that inevitably, you'll run out of space in the containers you have, and want more. You'll go to the store - and find that the container/case you bought before, is no longer made or sold (not really true for Stack-On brand multi-drawers - that's one reason why I like them - long-term availability); having all kinds of different style containers/drawers/cases/toolboxes makes for a storage nightmare. So invest early, and invest a lot. It won't be cheap, but it will be worth it long term.

The reason for number 2 is so you can easily identify and find your parts; you want to sort them and store them in logical groupings, so many of each type in each bin, with bins arranged in groups (so you might have a tackle box or multi-drawer of only resistors, and another for capacitors, and yet another for something else, etc). Also - always leave a few empty bins available in each case/container/etc - so you can easily expand (that's something that's nice about multi-drawer boxes, though - to expand, you just place and shift the drawers about - other solutions may mean you have to move parts, because the drawers/bins/whatever aren't removable - which can be a pain).

Whatever the system - it needs to -be- a system, and not just a mishmash jumble. Plan the system out beforehand - how you want it to look, how you want to arrange things, what kind of parts (and how many of each) you plan to have on hand, what the logical groupings will be. Once you know that, then you'll have an idea of how many bins/cases/etc to purchase, plus how many extra for future expansion.

Also - take a look around at your options, and try to choose the option that, should you need more in the future, you likely can get the same one (as I said, Stack-On has been pretty good in this regard). You might find something else. You might find that something "homebrew" works really well (baby food jars with the lids nailed/screwed to a board, for instance) - where the containers haven't changed much in decades. The ultimate keys here are consistency, labeling, and logical placement for storage.

Lastly - realize that doing it this way above will not be cheap - plan on spending a couple hundred dollars or so on storage. It will ultimately be worth it. I did this process last year, around this time - to my own shop. My storage solutions that I had in place was completely broken down and no longer serving a good purpose. I ended up spending quite a bit of money upgrading my storage (not just small parts either - I bought a few gorrila racks for shelving too) in my shop, and now I couldn't be happier (ok, I wish I had a larger shop - see the problem?)...

 ;D
5059  Forum 2005-2010 (read only) / Bar Sport / Re: Ordering basic stuff - what should I get? on: January 10, 2011, 09:57:14 pm
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two L293 or L298 h-bridge ICs seems fairly cheap at e-bay,

From what I've researched, ebay is the cheapest for those two components.

The difficult thing to find/buy though, are multiwatt-15 heatsinks; DigiKey has "something", but they don't show pics, and their part descriptions are none-too-clear. SparkFun has a large heatsink for those devices, but if you are wanting to encase your PCB, you'd need a tall box for that heatsink (or let it stick out).

I managed to find some heatsinks that should work OK at Apache Reclamation here in Phoenix, for only $0.15 USD each - but I have yet to find anyplace or anyone selling the nice thick heatsinks you see mounted on L298 driver PCBs and shields sold on Ebay (not sure why that is, you can get everything else on there).

Does anybody know of a good and cheap source for multiwatt-15 heatsinks?
5060  Forum 2005-2010 (read only) / Bar Sport / Re: Ordering basic stuff - what should I get? on: January 10, 2011, 07:02:43 pm
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2n2222a Transistors - already on my list

If you plan on doing anything with DC motors, or anything else that might need an h-bridge (or you want to learn about h-bridges), get the complement (PNP) of the 2n2222 as Ran mentioned (2n3906) as well.

Also - you might want to buy one or two L293 or L298 h-bridge ICs (note that the L298 can -not- be plugged into a breadboard or perfboard as-is - but it does have a higher current rating than the L293 and can be bridged as well - there are people and places online that sell adaptor PCBs). Once again (and especially with these parts, as they can eat into your budget) only buy these if you think you will be doing projects with DC motors (and even then, you might want to wait); I don't consider them expensive parts, but I don't know your budget, either.

Finally - you might want to think about (and perhaps purchase) something for storage of your parts. I always reccommend Stack-On multi-drawer bins, but they are fairly expensive, and you need the room for them, and they may not be ideal for your "workbench".

Another idea, though, that is fairly cheap and great for someone starting out (or someone needing portability), is a multi-tray fishing tackle box. The multiple fold/fan out trays are perfect for holding a multitude of small, easily scrambled-up parts (since that is what they are designed to help prevent), and there are generally compartments to allow you enough room for a small multimeter, a soldering iron, and some solder (and other "larger" items).

Just something to keep in mind...

 smiley
5061  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: January 10, 2011, 03:36:38 pm
Thansen: How'd you score such a nice board for free? If I wasn't already set up for the mini-ITX board in my project, I would love to have something like that (not that I need to reduce weight or anything, but smaller is always better on a UGV just for vibration sake).

Great find, though - however you did it!

 ;D
5062  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: January 08, 2011, 07:45:36 pm
Picked up another big batch of surplus parts from Apache Reclamation today:

  * some Figaro gas sensors (not sure what kind, I have an email in to Figaro)
  * several motors (DC, one stepper)
  * a couple of 12VDC fluid pumps
  * some heatsinks (for some reason, finding nice multiwatt-15 heatsinks isn't easy; the closest I came was some expensive beast from SparkFun, and something from Digikey - found ones at ARE for 15 cents each)
  * some MJ12005 NPN power transistors
  * a bunch of TO-3 insulators (plastic and mica - at least 200 or so)
  * LM350K TO-3 3A adjustable voltage regulators
  * a 555 (it looked lonely)
  * a Motorola RTL JK flip-flop (still in-package!) for my antique collection
  * some microswitches
  * some trapped-ball tilt switches

Plus a variety of 74xxx parts (most LS):

  * 74LS245
  * 74LS253
  * 74HC943 (woohoo - 300 baud modem!)
  * 74LS168
  * 74LS14
  * LM337
  * LM565
  * ADG412BN

All-in-all, some fun stuff; the motors were kinda on the more expensive side of things ($10.00 each for some), but the components were only about $1.00 each on average. Plus there were a few "gives" (like the gas sensors). It was a good day.

Oh - and I went to Goodwill and got a small New Bright R/C truck ($3.00), and two ATA100 3.5" removable drive docks ($3.00 each - still in shrink wrap).

 smiley-wink

/I've got problems... ;D
5063  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: December 28, 2010, 09:31:33 pm
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With the new firmware there are password protection, but only way to see the images is then to log in.

Do they leave a way to bypass this with the new firmware, so that you get the better stability of the new firmware, with the ability to run it "wide open"? I need to basically have it wide open to stream the data from the cameras to (ultimately) OpenCV for processing it (I imagine I could use curl or something to log in for me, but that's just an extra step that isn't needed - I don't need the security like you do, since the box will be behind the router, with WEP, MAC locking, and ultimately SSL encryption to the external browser).

Thanks for the info!

 smiley
5064  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: December 28, 2010, 03:05:22 pm
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I got one of those (just in metal chasing), but the original firmware on them sux, so instead I uploaded the yoics 9100a firmware instead.

Interesting - do you have a link or such describing the process (and/or why the original firmware stinks)? If it is really bad (I haven't even tried mine yet), updating it would be worth it...

 smiley
5065  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: December 28, 2010, 01:52:52 pm
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The 2.4 should have none of those problems, and should also have a better range with better picture, but I haven't tested those yet, but when my new wifitank is running, that will be the next thing I replace on it.

Some of those camera kits look similar to what I bought (though, once again, I don't recall if mine was a 900 MHz or 2.4 GHz; it might be that the 900/2.4 are frequencies for the US, while 1.2 GHz is for other countries?).

Something I recently bought with the intent of using it on my UGV project in the future was this:

http://www.geeks.com/details.asp?invtid=BLK-9100A-PLUS-N&cat=VID

It allows you to plug in four regular cameras (composite video) and view them via a built-in webserver over wired ethernet. Its powered off of a 5V 1A DC wall-wart (cameras are powered separately). Since my UGV has an 802.11g router/hub, I can easily plug it in (and power won't be an issue, since I'll have some fairly large 12 volt SLAs on-board).

Something to play with, anyhow!

 smiley
5066  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: December 28, 2010, 12:10:14 pm
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Also looking around for a possible wireless camera to go on this bot... if someone has suggestions, I'd love to hear em.

I've had great luck with a cheap wireless color "spycam" I bought on ebay years ago (can't remember if it was 2.4 GHz or 900 MHz). Its a little camera that has an antenna, along with barrel inputs for 9VDC (use a small 9V battery - it came with an adaptor), plus an RCA output for video (if you wanted to hard-wire it). It transmits to a small receiver box with antenna that outputs NTSC composite video for a television. I've had no problem with it transmitting all over my house via a small test-rig UGV (unmanned ground vehicle) rig I made a several years back. So, about a 100 foot range (probably much greater on open ground with line-of-sight).

At the time I got it for about $30.00 plus shipping (drop-shipped from HK); you can probably find something similar...
5067  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: November 27, 2010, 03:48:04 pm
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Two fresh dungeness craps, first of the season.

Well, you must be feeling better!

 ;D
5068  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: November 18, 2010, 06:19:17 pm
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And would be a "stupid" thing to make, because all it probably will be able to power, is itself, and I am not even sure it can do that...

You'd probably have no problem doing that, as long as you ran the code on some timer interrupt (say every 30 seconds or longer), and went into a low-power sleep mode otherwise; you could probably easily keep the battery charged to run other things including the Arduino and the servos...
5069  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: November 18, 2010, 05:51:58 pm
[edit]And my little test setup[/edit]

bld:

A friend of mine has a similar setup, and bought (I think) nearly the exact same parts. He's using them for some kind of gardening monitor system, and says they work really great.

 smiley
5070  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: November 17, 2010, 10:39:25 pm
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I've been trying to cut back on that sort of thing.  In fact, I've recently been taking some things that I rescued out of work's dumpsters BACK to work's dumpsters.  I mean, a working perfectly 386sx PC is nice, but ... not really worth the space it takes up, anymore.  I don't want to end up on "Hoarders."

I used to have a 386 motherboard that I still kick myself over for "getting rid of". There are some graphics demos for the PC that won't work right on anything but a real 386. It was a nice board, too - mini-AT, stocked with 8 MB of simm, AMD 386DX40 IIRC.

 :'(

I know what you mean, though. I'm approaching "critical mass" with my collection of old Polaroid cameras I've purchased over the past few years for the ultrasonic sensor. My intent is to tear 'em down, keep all the good parts (motors, optics, etc), recycle the rest. I've also got a couple of VHS cameras that need to be torn down, too. And RC cars...

Ugh - maybe I need to be on "Hoarders" (I don't have paths yet, and everything is fairly neatly stored - so I don't think it counts!)...

 ;D
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