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Geek Culture / buying components not in bulk...

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Code eater
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Posted: 22nd Feb 2011 13:54
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Hey,

I am into making a electrnic products. I have two projects on the go at the minute. For one I need a MAX3323e chip and for the other an AD7819 chip (Don't know how many of you will know them). However, I am finding it impossible to buy them unless I buy 100+. This is unfeasible and so I don't really know what to do.
Where can I buy pretty irregular chips in their single form?

thanks

If pots and pans were "if"s and "and"s there would be no work for programmer's hands...
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BatVink
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Posted: 22nd Feb 2011 14:16
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What country are you in? In the UK, you can get these things from Maplin.

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Neuro Fuzzy
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Posted: 22nd Feb 2011 16:12
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Have you tried digikey?
http://www.digikey.com/
sparkfun might have it also.

Also... you might want to look into getting a more general chip for hobbyists, like an ATMega32 sumthin. Maybe even an arduino. The ATMega328 has several ADCs, and is like $4 on sparkfun.

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Code eater
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Posted: 22nd Feb 2011 18:14
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Im in the UK. I tried searching the maplin site, but nothing came up :S

Digikey looks good! Thanks.
Thing is, I need an ADC with a sample rate of 44k+ which I don't think ATmegas will do, will they?

thanks

If pots and pans were "if"s and "and"s there would be no work for programmer's hands...
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Neuro Fuzzy
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Posted: 22nd Feb 2011 21:36
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hmm... I haven't done much with the analog to digital converters on ATMegas... but this looks promising: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1208715493/0

it seems to be pretty accurate with a fast sample rate (~56khz)

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Code eater
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Posted: 23rd Feb 2011 19:21
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Thanks guys, but I just managed to buy the chips I need from digikey. Having said that, they did just say that they are out of stock, so I may have to reconsider...

If anyone is interested, i'm trying to make a loop pedal for my guitar since they cost about £150 I thought it would be worth the effort...

Cheers

If pots and pans were "if"s and "and"s there would be no work for programmer's hands...
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The Wilderbeast
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Posted: 23rd Feb 2011 19:44
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One thing you might want to have a look at is a DSP kit, such as the one sold by TI here. It has all the ADCs and DACs built into the board and comes complete with an IDE etc.


Blitzwerks | Indie Development Team
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Interplanetary Funk
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Posted: 23rd Feb 2011 20:08
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try these places:
http://www.rapidonline.com/
http://uk.rs-online.com/web/
http://uk.farnell.com/

Get on my level
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Code eater
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Posted: 24th Feb 2011 12:24
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@the wilderbeast
I am considering taking it as an AS project (not that I am under 18 or anything ) so I think I will have to build it from scratch. Cheers anyway.

@planetary Funk
Rapid don't have them - they are my standard suppliers. The other two do though, I will consider buying from RS as they are about half the price of farnell. THANKS

If pots and pans were "if"s and "and"s there would be no work for programmer's hands...
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Interplanetary Funk
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Posted: 24th Feb 2011 13:49
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no problem, those 3 are the best in the UK as far as I'm aware and they're also where my college buys our components from so they're obviously trustworthy.

Get on my level
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The Wilderbeast
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Posted: 24th Feb 2011 15:35
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It depends what you're doing. If the focus of the project is on the actual DSP work itself then it's acceptable to do this.

I built an amp modelling + power amp combo for my A2, I didn't design the power amp (although I did have to solder 100 odd SMT components ), but I did do all of the DSP work. It's funny because the people marking it don't have a clue what you're on about


Blitzwerks | Indie Development Team
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Code eater
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Posted: 26th Feb 2011 19:30 Edited at: 26th Feb 2011 19:47
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@planetary funk
My college gets stuff from rapid, anywhere else the teacher throws a little fit

@the wilderbeast
My focus is on building it as well as the DSP.
I'm hoping the DSP won't be too complicated, I'm basically just recording a few 8-bit samples and then playing them back through a DAC...
I'm really just doing a prototype at the minute but as it stands it is like:
Guitar > Op-amp > ADC >Processor (ATMega644p) > DAC > voltage splitter (to return back to original voltage) > Amp

However, thinking about it, i'm going to need more memory. The ATMega644p only has 9kb and if i'm sampling at about 100-150 samples a second, thats not even going to last me a second :S.

[edit] what am I talking about? It has 64kb flash, but then thats still only about half a second of sound. [/edit]

[edit]By my calculation, at a sample rate of 100ks/s I need about 3mb of memory just to hold 30 seconds of sound, which should be enough. I'm going to need some pretty fast memory though... a write time of about 10 uS

If pots and pans were "if"s and "and"s there would be no work for programmer's hands...
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Interplanetary Funk
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Posted: 26th Feb 2011 20:35
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you can get NAND flash storage chips up to 4GB for about £30 on farnell I think. Most of them use SPI or TWI to communicate with the MCU and I know that the 644 Has SPI AND TWI so it won't be any problem xD

Get on my level
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