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1  Using Arduino / Project Guidance / Re: relay control on: August 05, 2014, 09:36:05 pm
sorry I was rushing and causeing confusion.  This is the relayboard I am using
http://www.sainsmart.com/4-channel-5v-relay-module-for-pic-arm-avr-dsp-arduino-msp430-ttl-logic.html
10A perrelay.  It has a jumper so the coil supply can vbbe fully optoisolated from logic power if desired, or connected together for simplicity.
2  Using Arduino / Project Guidance / Re: upload sketch to 2560 with usb-serial cable? on: August 05, 2014, 09:21:59 pm
that is the best news, thank you!
3  Using Arduino / Project Guidance / upload sketch to 2560 with usb-serial cable? on: August 04, 2014, 09:42:03 pm
If I build my own "mega" board but leave off the USB adapter chip, can I just plug a USB-TTL cable into UART0 and upload a regular sketch to the 2560, assuming I loaded the bootloader already w/a dragon or somesuch over ISP?
4  Using Arduino / Project Guidance / Re: relay control on: August 04, 2014, 09:36:54 pm
if yo ugot ur circuit working then keep going, but if you didn't  I suggest a sainsmart relay board like
http://www.sainsmart.com/sainsmart-4-channel-signal-relay-board-for-arduino-uno-mega-2560-r3-duemilanove.html
if you have a big amount of current that needs switching it makes things simple, just note high turns off the relays and low turns em on.

Big power relays are a little tricky and you need to think about things like freewheel diodes etc on the coils, but a board like i linked to has that built in I belive.  I have an older model of ahtt myself.  another ME here playing w/ electronics.
5  Using Arduino / Installation & Troubleshooting / Re: How to check and change the usb port on Linux? on: May 23, 2014, 08:07:55 pm
I had a similar issue a long time ago, but the group was UUCP for me, so you can add yoruself to both groups, orone at a time to see which fixes it.  IMPORTANT! you must remember to logout and in again for changes to take effect.  I didn't realize thisand spentmany an hourtrying to troublshhoot a problem I had fixed lol
6  Using Arduino / Installation & Troubleshooting / Re: updated from 12.04 LTS to 14.04 LTS and can'tupload to mini on: May 17, 2014, 10:44:19 pm
bumping out of  desperation, fiddled w/ some old fixes (setting my udev rules like used to be needed) that did not seem to helpin any fashion.  aarrgh
7  Using Arduino / Installation & Troubleshooting / updated from 12.04 LTS to 14.04 LTS and can'tupload to mini on: May 14, 2014, 05:50:01 pm
so I have a mini, and I am trying to upload code and am getting a perpetual "programmer not in synch" message.  the reset button wasn't helping so I dug in a bit harder and found this in my log

May 14 18:36:25 beefcake kernel: [  988.660278] usb 7-1: new full-speed USB device number 2 using uhci_hcd
May 14 18:36:25 beefcake kernel: [  989.192286] usb 7-1: device not accepting address 2, error -71

so I am suspicious of a system config problem, not a hardware one.  I have not tried to uploadany code since updating ubuntu a few days ago, so I blame that!  I am running a 32 bit systim FWIW, please let me konw if  I can provide more info to help you help me.
8  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.
9  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.
10  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.
11  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.
12  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?
13  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.
14  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.
15  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.
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