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1  Using Arduino / Audio / Re: Small Class D amplifier on: April 17, 2014, 03:19:21 pm
true, but as most amps are in the 15-30 watt range, with only a 12 v supply we are talking 10 watts peak RMS, maybe 1-2 watt average RMS on an 8 ohm speaker. (yeah its a wierd wave, normal math need not apply)  so I should have plenty of overhead to play with.  Most amps are rated at higher power to 4ohm, but if I need even more kick I don't think I've ever seen more than one datasheet that spec's to 2ohm.
as for class D being analog, yeah I get that, hence the quotes, but some qty of noise must get thru, and there are strange things that can happen when you are not playing by all the normal rules, which I am.  And when a problem is harder than you are smart, the best thign to do is just build the damn thing, take some measurements, and see if you need to worry or not then, not earlier! lol.

oh and no, II have not yet looked at the specs of ANYTHING posted here, bookmarked em to look at after lunch.
2  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 17, 2014, 03:07:18 pm
...I forgot that there is such a thing as a usb-ttl CABLE.  I only have boards that I plug into a cable...

the big reason for doing this was to make it so I don't need to have a breakable board w/ me to upload new firmware, and these things get updated often.  I'll think abou tthe cable, but I already have some real nice panel mount USB connections I'd like to use, if for no other reason than they look pro as all hell and make me feel fancy.
3  Using Arduino / Installation & Troubleshooting / Re: Sketch-Upload via USB/ TTL-Adapter does'nt work ... on: April 17, 2014, 03:04:35 pm
[snip]
Press reset on the promini when the IDE shows "Compiled xxx of 32xxx bytes".
If you select File:Preferences and turn on verbose outputs, can be easier to time the press correctly.
[/snip]

oh man thank you!  I have always had issues w/ certain sketches uploading and needing to well-time a reset, that will maake it so much easier.
4  Using Arduino / Audio / Re: Small Class D amplifier on: April 17, 2014, 03:02:12 pm
wow that's a lot of sources quick, thanks guys!  I'll take a look at em now. 

@retrolefty and DVDdoug:  I meant put the speakers in parallel, not the amps, so I can drive more power at the same voltage.  However since class D amps are 'digital' I figure they are a bit harder to predict how they will behave outside of thier rated range of loads compared to AB amps.  Gotta dig into the datasheets to konw for sure.  stupid low voltage supply, BUT since it is so close to automotive range, I know there must be devices out there specifically for it.
5  Using Arduino / Audio / Small Class D amplifier on: April 17, 2014, 11:50:45 am
If this isthe wrong forum and this should be in electronics, please move, but this seems right...

So I need to amplify a small pulse, with modestly high peak power and low average power.  Battery life is concern #1 so I am looking at class D amps.  Power needs are still up in the air, but probably on hte order of 5W.  I am currently using a TDA2030 which is a lovely but obsolete monolithic AB amp that is super easy to use, but I want to try and up the efff w./ a class D.  The catch is since it is battery powered, I want to stick with a single +13v supply to keep things simple and not have a neg source eating up power.  THe pulse itself is only positive going, so there is no need for a negative supply anyways.  output will be into a speaker network, i am hoping I can put several in parallel to dropthe eff resistance to whatever the minimum the amp can handle will be to try and boost the power, otherwise I will need to boost the amp voltage which is not a thing i want to have to do.

So tell me, does anyone know of a low power class D amp that comes as an all in one chip, and can be run from a single supply?
6  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 17, 2014, 11:41:14 am
[snip]
They can be soldered to a main board - or socketed.  They can be fitted over other parts making the design more compact in the process.
[/snip]

ah yes, forgot that is a plus.  I am socketing some other boards because they require smt chips w/ sink pads underneath so I don't want to tackle dealing w/ them right out of the gate and I already am stuffing parts under them so I guess the abovce linked module or equiv ain't the worst idea.
7  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 17, 2014, 11:38:13 am
well seeing as how manufacturers of d-sub connecters call DE-9 units DB-9 in data sheets, sometimes 232 is close enough... :roll: hate that game.

Now my purpose is a very small production run, but I will need to update the firmware on the arduino likely fairly often, and inthe field (literally outside) and the big catch I  didn't mention is I will have for teh time being two seperate arduinos on the board untill I sit down and optimize my code.  Current plan is a single usb cable soldered directly to the board (hate connectivityissues) with a panel mount USB port, along with a 4 position dip switch to swap the output of the usb-ttl converter from one areduino to the next.  seems elegant enough, just a shame I need to physically get to the board  to do the swap, defeats the sexyness of the panel mount connector. might just  double up hte USB ports for now.
8  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 15, 2014, 08:39:47 pm
I am liking going with the FT232 or equiv as it lets me leave off one more ISP header, and one less thing to worry about, it either just worksout of the box, or will never work.  No software to mess up etc.  The whole goal here is to condense, so as new daughter board is a bad idea, I want it a permanent part of the pcb, so I just need to sort this out.  Pro boards, small quantity, but I will probably be hand soldering them all, maayyyyybbbbeee ghetto reflow, but not at first, so there is deff a minimum package side I can deal with, and no center pads!

thanks, wish me luck.
9  Using Arduino / Microcontrollers / FT232 vs 16u2 on: April 14, 2014, 01:52:30 pm
So I am looking to finally make a custom arduino board with my circuit and ancilliaries on it, and am trying to figure out the best way of putting USB connectivity on it. I am looking at the mega and see that the arduino folks updgraded from a Ft232 to using a 16u2 to give USB chitchat.  I always thought the FT232 was expensive hence the move away from it, but the priceing is the same.  However hte 16u2 takes a lot more support hdw, so I am wondering what the benfit is to the more complex circuit w/ higher parts count.  It seems easier to just throw a ft232 at it rather than deal with uploading code to a complex 16u2.

any input?
10  Using Arduino / Project Guidance / Re: using the PINxn Register on: December 27, 2013, 11:36:34 am

You haven't said why you can't use (for example) pin 13 on one device and pin 2 on another. It can be a very simple solution.

...R

Becasue I am lazy and dumb.  I want to be able to wire up any and all devices the same (physically) and flash identical firmware to it and have it "just work" rather than have to keep good notes and remember which model I am playing with etc. As for your comment on how #define will substitute, I tHINK I am right, but I am looking in a book right now t osee for sure which one of us wins a prize on this one.
11  Using Arduino / Project Guidance / Re: using the PINxn Register on: December 19, 2013, 08:30:37 pm
so to clarify my reasoning, here it is,

#define is dangerous because if you have #DEFINE pinA 13, then if you have a variable called pinAstate, at compile time that variable become 13state, and will fail to compile.  seemseasy enough to avoid, but one mistake could go unnoticed for a long time and be quite hard to track donw in alarge program, so I am using consts, to give the complier a hint of "hey man, you can probably optomize this somehow" as that is my understanding of what it does, along with throw up an error if  Itry to change its value, which is nifty as it basically forces me to adhere to my own design intent and not kludge (too much).

as for why use direct port maniuplation for speed and then slow it down by creating my own tools like this, well theoretically if I can have a compiler level modification (like #define, but preferably safer) that will be translated into a SBI or whatever magically by the complier adn be just as blazing fast on the arduino itself.

now I can't just say "I'll stick to portb3 on all arduinos" because on some that may be digital pin 13,on athoer it could be digital pin 2.  if/when I find an elegant solution I will post it here, currently I am using ifdefs which are meh.  it works but very quickly 10 lines of code is 40 and it gets less readable, everythign is a trade off you know.
12  Using Arduino / Project Guidance / using the PINxn Register on: December 18, 2013, 09:48:58 am
so I wnat to toggle a pin in a ISR, so I figure I should do it as fast as possible, and it looks like the smartest way of doing that is to set the PINxn register.  now I have been trying to make my code easy to modify by using #define for any direct pin/port access as this code is run on both a mega and a mini, so just changing the contents of a #define is much easier to catch all instances, but I dont like using #defines ass they are so damn powerful.  is there a way to use the arduino library to translate from a digital pin number to a port number?  I know all the info exists in the corel i braries, i just don't know if I can use some magical function call that the compiler will then optomize down to just a SBI or CBI command.
13  Using Arduino / Programming Questions / Re: 'simulate' arduino math on: December 12, 2013, 01:48:52 am
thanks guys!  good to see I was on the right track.  And yes the pseduo code is horrble, but that was my intent.  I want to see my failures so I can get a good idea for exactly how the math goes down.  for example one that always drvies me up a wall with doubt is type casting.  IE are all those values of c the same, I figure the last two are, but the second one has me unsure. 

int a = 10;
int b = 3;

float c = a/b;
c = a/(float)b;
c = (float)a/b;
c = float(a)/float(b);
14  Using Arduino / Programming Questions / Re: tone library error on: December 11, 2013, 11:27:50 am
wait I am sorry, my memory is still fuzzy, but tone is already a part of the core arduino library.  You probably shouldn't use the rougecode version of tone unless you absolutly must.
15  Using Arduino / Programming Questions / Re: tone library error on: December 11, 2013, 09:38:46 am
ohhhh, I had an issue with tone too, but I fixed it but can't remember how... Let me see if I have any notes lying around.  I don't remember how I fixed it, or ifi twas my sketch or the library.
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