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46  Using Arduino / General Electronics / Re: Small power source for one century on: January 27, 2013, 12:59:01 pm
There are batteries based on tritium that are supposed to (theoretically, not promised) last hundreds of years.  Just google "Nano tritium battery"

You need deep pockets though.  I think I read somewhere they were nearly $2000 each.

http://www.betavoltaic.co.uk/citylabs20yearnanotritiumbattery.html  these? That dip package looks so cool smiley-grin
47  Using Arduino / General Electronics / Re: Small power source for one century on: January 27, 2013, 12:47:19 pm
I'm still working on getting it made a recognised SI unit smiley-wink

Hampshire, at the moment... until the work runs out anyway! My landlord used to do a lot of work around Crawley.
48  Using Arduino / General Electronics / Re: Small power source for one century on: January 27, 2013, 12:43:10 pm
I wonder could you do it with bacteria somehow? Bacteria + shitload of food for them = heat.
49  Using Arduino / Audio / Re: Synthesizer with Arduino on: January 25, 2013, 01:39:22 pm
This could get very complicated very quickly smiley Why not try starting off with a block diagram of all the elements in your system, and the audio/control signal flow between them, then flesh that out into schematics for each element, building and testing each one separately to see how things work.

If you want nice filters, you're probably going to have to actually build those rather than doing it in software. Maybe some of the more senior coders here with vastly more talent than I have will disagree, but I can't see that working out too well in software on an Uno.
50  Using Arduino / Project Guidance / Bare minimum investment for playing with OpenCV? on: January 23, 2013, 02:42:40 pm
I was asked about this by a friend and thought I'd re-ask it here as I didn't know smiley If someone wanted to play with computer vision for the purposes of optically tracking a moving target, what sort of kit would he need to buy as a bare minimum for learning the basic principles?

The brief is for an airsoft/paintball smart sentry gun that should only react to something that looks like a person, and follow it once within it's field of view... as far as I'm aware time and money are no object but the initial outlay should be as low as possible in case of a "waaah it's too hard" meltdown smiley
51  Using Arduino / General Electronics / Re: Best Capacitors on: January 23, 2013, 02:28:30 pm

"I know I only need one ne555, but for another dollar I can have 10!"

...but you'd never go without festive blinkenlights ever again smiley-grin
52  Using Arduino / General Electronics / Re: Capacitor side on: January 22, 2013, 05:15:50 pm
There's a problem with your attachment, could you re-upload it? Perhaps it's non-polarised... polarities are normally marked pretty clearly with a bold stripe or something similar.
53  Using Arduino / General Electronics / Re: Best Capacitors on: January 22, 2013, 04:44:55 pm
I would think 5-10% tolerance would be ok for general use, tinkering and experimenting. Don't pay over the odds for precision you don't need.
54  Using Arduino / General Electronics / Re: Best Capacitors on: January 21, 2013, 04:34:38 pm
Just get a ton of different values, then you'll be sorted out for all kinds of experimenting!
55  Using Arduino / General Electronics / Re: Best Capacitors on: January 21, 2013, 02:52:21 pm
Any of the big-name retailers really... Farnell, RS, DigiKey etc. Or, if I just wanted a cheapo bumper pack of different values I might order from one of eBay's HK-based sellers.

You may be able to pick up something like this https://www.sparkfun.com/products/10003 but bigger, for a lot less money, if you don't mind waiting a few weeks for it to arrive.
56  Using Arduino / General Electronics / Re: Best Capacitors on: January 21, 2013, 02:33:27 pm
Given the options I'd go with ceramic there smiley
57  Using Arduino / General Electronics / Re: Best Capacitors on: January 21, 2013, 02:30:40 pm
Your capacitor selection depends entirely on it's role in the circuit. Different ones are best for different applications, that's why there's so many! I'm sure one of the senior members here would elaborate further on which types are most used for what. What circuit are you using them in?
58  Using Arduino / General Electronics / Re: Mystery magnetic sounder problem on: January 21, 2013, 02:26:38 pm
No idea, Lefty! It's not my design smiley But the test itself has been unchanged for years... I can only assume those who designed the setup know what they're doing.

The sounders don't actually come with seal tabs on them (which seems odd, as all the ones I've actually bought came with them and I don't normally pull them off until I'm done with them). If the IPA has done something horrible to the innards then I suppose there's little I can do other than apologise and make some more...

I wonder, is it worth opening one up completely to investigate any possible internal damage? We've got thousands on the shelf so I could compare a new one to one that I've molested to see if there's any difference.
59  Using Arduino / General Electronics / Re: What is electrical noise? on: January 21, 2013, 12:08:25 pm
Electrical noise is unwanted signals causing undesired operation. Imagine if you're trying to listen to a faint tone against a background of loud static... in simplest terms it's a little bit like that.

EDIT: Here's a thing on RC filters to get you started.

60  Using Arduino / Displays / Re: small LCD displays 6 chars across? on: January 21, 2013, 11:52:05 am
http://www.newhavendisplay.com/nhd0108hzfswgbw-p-212.html

A quick search turned this up... it's 8x1 rather than 6x1, but maybe it'll do? I'll keep searching and see what else I can find.
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