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16  Using Arduino / General Electronics / Re: Dumb down MOSFET Selection? on: May 06, 2013, 02:25:42 pm
A few weeks ago I read (it could be on this forum) that the TO-220 could not have 100A through the pins, even though the mosfet was specified for that amount of current.


I wondered about that myself... having worked a fair bit on big-ass electrical installation jobs and seeing the size of conductors needed to handle 100A, I thought seeing TO-220 packaged parts being rated for hundreds of amps seemed a bit ridiculous!
17  Using Arduino / General Electronics / Re: General book to learn Electronics from zero? on: April 28, 2013, 12:47:28 pm
http://www.amazon.co.uk/Forrest-Mims-Engineers-Notebook/dp/1878707035

I used to have a bunch of books by this author. Definitely worth a look smiley
18  Community / Bar Sport / Re: What have you made out of old circuit boards? on: April 24, 2013, 12:20:26 pm
I once had the idea of tiling a wall with old ceramic PGA-package CPUs, with the gold lids on them. I still might, one day.

Hard to do unless:
1) You are made of money
2) You already have a fair size collection of these CPUs
3) Your household average height is that of the Yoda or hobbits

These processors are hard to come by nowadays. You can pay $20-30 each on ebay and they don't all look good, mostly because they are headed for gold extraction. I happen to be a collector. It's harder and harder to get those gold lids. If you want a pentium pro or other bad boys, be prepared to pay $40 each. I'd be interested in making a belt buckle with one of these if I know how to make belt buckles.

All very good points smiley Just a beer-idea really... awesome but impractical/impossible. But there IS a lot of e-waste out there, and a lot of people who don't know what they have. The other killer is that my ambition often outstrips my patience. I'd get one wall of the shithouse done and give up  smiley-razz
19  Community / Bar Sport / Re: What have you made out of old circuit boards? on: April 22, 2013, 11:50:07 am
I once had the idea of tiling a wall with old ceramic PGA-package CPUs, with the gold lids on them. I still might, one day.
20  Using Arduino / Audio / Re: Decoding CTCSS - Possible? on: April 15, 2013, 12:18:05 pm
Maybe try a Teensy 3.0? Give yourself a bit of extra processing power smiley
21  Community / Bar Sport / Re: How would you end your life? on: March 26, 2013, 03:54:38 pm
By complete surprise, and hopefully not preceded by "of course I know what I'm doing" or "hey guys, watch this!"  smiley-cool

22  Using Arduino / Project Guidance / Re: memory on: March 22, 2013, 12:38:42 pm
As far as I know, code can only be executed from internal flash memory. For beginner-level projects you're probably not going to run out.
23  Community / Bar Sport / Re: The pcDuino? on: March 05, 2013, 12:58:43 pm
Looks useful... I would probably take the bait if it really CAN be programmed properly in an Arduino-style environment (I simply don't have the time to learn anything more complicated). Having that level of simplicity paired with absolute pissloads of RAM/CPU power would save me having to make a lot of compromises. I don't really mind it running something Linux-y in the background as long as I can still make it do my bidding with as much ease as one would with an Uno etc.
24  Using Arduino / Project Guidance / Re: What would be the easiest way... on: February 25, 2013, 02:40:03 pm
I'd usually go for the MAX7219. Even my wanky ebay clones seem to work alright smiley
25  Using Arduino / General Electronics / Re: Can i make a arduino from a old pc? [solved] on: February 24, 2013, 02:21:16 pm
Best thing to do is recycle it responsibly then smiley But keep the power supply, they can be quite useful if it's not damaged in any way.
26  Using Arduino / Project Guidance / Re: arduino +100Mhz radio jammer on: February 24, 2013, 12:09:54 pm


I think I can hear them starting to rattle and shrink already smiley-wink

27  Topics / Device Hacking / Re: how can i run arduino IDE on android? on: February 24, 2013, 10:29:35 am
For what it's worth (probably not a lot!) I abandoned any bright ideas of "I want to put the Arduino IDE on my tablet!" pretty quickly because of all the reasons detailed above.

I can't see coding on a touchscreen being much fun anyway.

28  Using Arduino / General Electronics / Re: Can i make a arduino from a old pc? [solved] on: February 24, 2013, 10:13:01 am
How old is this old PC? The guys above me are right - you can't make an "Arduino" out of one, but if it's of a certain age (we're talking early/mid 80s and green/black screens here!), you may still be able to salvage some useful bits out of it.

On VERY old kit, you sometimes see MCS-48/51 family microcontrollers used for keyboard scanning processors and other low-level pin twiddling tasks. These may be useful, but are also a pain in the arse to harvest and do something with. If they're not socketed it can be quite hard to de-solder a 40 pin DIP and extract it without damage.

Also, they are probably mask-programmed with no provision for you to burn code directly on to them, and far less than 1kB of SRAM. So, you would need to set them up to execute instructions from external memory, and provide this memory for them. An EEPROM to hold your program code, and some SRAM, and more than likely some I/O expansion chips depending on what you want to do. Then the address decoding logic... and either learning some assembly language for them or finding a suitable C compiler. It's certainly do-able, you'd end up with something a little bit like this.

But, in the time it took you to do all that, you could have gone to work and earned enough to buy several nice genuine Arduino boards smiley Your call.
29  Using Arduino / Project Guidance / Re: 16bit DAC parallel bits, AD669 on: February 24, 2013, 09:56:54 am
Why not use a serial DAC instead? I'm pretty sure you can get some reasonably fast single channel ones and you might find it easier to implement. If you can't find one in a package you like then there's always the option of a breakout board.
30  Using Arduino / Project Guidance / Re: Infrared Laser spotlight on: February 24, 2013, 09:53:21 am
Back in my Airsoft-playing days, most if not all sites I played at where night games were organised had an outright ban on IR lasers (presumably for use with Gen1 night vision gear) as they were not considered "eye safe". I'd go with LEDs and just keep adding more until you achieve the desired effect smiley
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