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5116  Forum 2005-2010 (read only) / Bar Sport / Re: Homebrew Waterfall Display HOWTO on: January 15, 2011, 08:53:27 pm
That's a very good point, Fenrisulfr - something worthwhile to keep in mind...
5117  Forum 2005-2010 (read only) / Bar Sport / Re: Homebrew Waterfall Display HOWTO on: January 01, 2011, 04:25:29 pm
My initial thought about the actuator is that it still sounds kind of leaky.

Yeah, it really does, doesn't it? I tried to find rubber coated steel bearings/balls but had no luck, thinking such a thing could be used to seal it better. Perhaps if the idea of a cutoff nail were used instead of a ball bearing, you could dip the nail into some silicone glue?

Also - I'm not sure if minor occasional drips, at least for a homebrew system would matter in the end. As long as it wasn't a steady drip, nor a stream, it probably wouldn't overall matter (think of it as a bit of 'static' in the display).

But I am not trying to defend my design; it was the best I could come up with in a very short amount of time. Maybe a two-way magnetic driver, with a second coil around the bottom of the tip, to draw the ball downward to seal the tip? It would be current intensive, but possible...?

5118  Forum 2005-2010 (read only) / Bar Sport / Re: Homebrew Waterfall Display HOWTO on: January 01, 2011, 03:07:48 pm
how about something using a similar principle to bubble jet printing technology?

Based on what I read here:

I don't know whether such technology could be adapted to a continuous circulation fountain (which is what one of these displays ultimately are), or whether such technology could be fabricated at a larger scale by a hobbyist, or whether such technology would even work at larger scales.

Furthermore, since inkjet technologies rely on propelling droplets, whereas in the videos of the waterfall displays, you can see only gravity is being used (plus there's the fact that if the droplet nozzles were pressurized, the change in pressure from opening one or more would have a cascade effect on the amount of pressure behind others falling - which may or may not be difficult to compensate for in software).

But the idea is interesting - right now, no matter what, the goal to achieve this at a "homebrew" level is getting the cost of the valves to a low price per valve; such a system would need at minimum 5 valves to make characters (5x7), but more valves would be wanted to make the kind of effects shown in the videos (probably 64 at least on the low end, 100+ on the high end). If a valve cost $5.00 to make, such a fountain/display would get expensive quickly (though still much cheaper than the shown fountains, most likely).

I think my idea, if it worked, would bring the cost down to less than $5.00 each, possible much less (maybe even $1.00 each). But all options and ideas are worth trying and investigating, because they might lead to cheaper options.

One possibility might be to instead replace the ball bearings I noted with perhaps short lengths of a nail of similar diameter, with the tip of the nail ground or filed to a rounded point; that would entail more work, but might be cheaper than the ball bearings (though the steel bearings from are pretty cheap already).

5119  Forum 2005-2010 (read only) / Bar Sport / Re: Homebrew Waterfall Display HOWTO on: January 01, 2011, 01:46:39 pm
I'd start by building around the TPIC6B595 chip.

While that would be a good chip to control the system with, I think ultimately one needs to start by first verifying if my valve idea would even work!


The controlling code and hardware can come later; what should be done is to build a simplified singular form of the valve. The idea is to have a valve that operates so that singular drops can be formed, with no pressure (other than gravity) behind the water droplets. Plus, the valve needs to operate at high speeds/cycles.

Such valves are possible to purchase, and I am sure that the videos of these displays use such valves; but they are anything but cheap. So my goal was to come up with a solution that could be implemented cheaply (though not easily).

If a singular valve worked (or if the idea could be used to make a cheap valve that worked), with perhaps it being controlled by an Arduino via a simple transistor switch - it would prove the concept, and that perfected valve could then be used to build the larger device.

Which leads me to wonder if a singular form of the valve wouldn't perhaps be useful in some manner to those who do water-drop photography...hmm.

5120  Forum 2005-2010 (read only) / Bar Sport / Homebrew Waterfall Display HOWTO on: January 01, 2011, 03:32:57 am
All - I wrote the following up for the Electro Tech Online forums, for a thread discussing such a system; I thought maybe some of you might want to see it. I'm hoping that it may help lead someone to build an inexpensive homebrew version:

Homebrew Waterfall Display HOWTO @

The thread on the Electro Tech Online forums is here:

Electro Tech Online: Waterfall Printer


5121  Forum 2005-2010 (read only) / Bar Sport / Re: Want: old processors Have: arduino shield on: December 22, 2010, 11:30:29 pm
How difficult to get something like that? Who would have saved 3 new processors just to beat me?

It seems strange that it is only three, and not four; I would expect a multiple of 2 for use in a multi-processor system of some sort (where getting them all from the same batch might've been needed - sequential numbers was likely some kind of "from the same box of processors" OEM thing or something).

Maybe at one time it was like that - but then one processor died and had to be replaced, and you got the remainder?

/just a wild-a** guess...

5122  Forum 2005-2010 (read only) / Bar Sport / Re: Want: old processors Have: arduino shield on: November 26, 2010, 03:32:44 pm
I could get you tubes of 6809P processors if you wanted them. I know I have a few Z-80s kicking around my shop. I have some other weird chips, some without markings that I know are CPUs (or DSPs), that might have been for demo use (they might be slugs, for all I know). At Apache Reclamation, I could probably dig up all sorts of weird old CPUs and such (I've bought two different kinds of core memory from them - and an Altair!).

5123  Forum 2005-2010 (read only) / Bar Sport / Re: Sparkfun overpriced on: July 13, 2010, 10:31:10 am
we need manufacturing too people here in the states too

Does Atmel have a plant here in the US?

For that matter, are there any electronics (resistors, capacitors, transistors, ICs, etc) manufactured in the US anymore? Or are they all designed here, then uploaded to a factory in (pick the country), fabbed, then shipped back?

How do you compete with ultra-cheap labor, lack of labor laws, and lack of environmental standards laws? How do you compete with lower taxes?
5124  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.

5125  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!):

5126  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?)...

5127  Forum 2005-2010 (read only) / Bar Sport / Re: Ordering basic stuff - what should I get? on: January 10, 2011, 09:57:14 pm
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?
5128  Forum 2005-2010 (read only) / Bar Sport / Re: Ordering basic stuff - what should I get? on: January 10, 2011, 07:02:43 pm
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...

5129  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!

5130  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).


/I've got problems... ;D
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