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16  Using Arduino / General Electronics / Re: Is arduino equiped with AC protection? on: December 30, 2012, 04:04:07 pm
The offset is used often in single supply audio circuits, the signal is amplified around the offset to amplify the full range of the signal and then the dc component removed before the output
17  Using Arduino / General Electronics / Re: Is arduino equiped with AC protection? on: December 30, 2012, 04:02:02 pm
Ah missed that analog read part, you want to read that full 18v spectrum? And don't trust your meter, dc and ac voltage reading aren't perfect especially if both are present at the same time, it could be just pulsating dc not ac or a more complex waveform, you really need to oscope it to know what you are dealing with, you could be trying to solve a nonexistent problem, either way a voltage dividerlike he suggested would be fine, and if you are unsure a 5.1zener used correctly will ensure the voltage after the divider is between 0 and +5v
Basically the zener cathode (+ or banded end) will go to the input, cathode to ground and you will be protected
This would be after your voltage divider
18  Using Arduino / General Electronics / Re: PCB Routing Tips? on: December 30, 2012, 02:09:01 pm
My tip would be if you had the time to manually route the whole thing, on my projects I always do that and make every trace basically as big as possible (within reason) , also paying attention to special or sensitive traces or routing noiser ones elsewhere, I actually usually place components not where the ratsnest is easy but where. Its best for electrical reasons, with enough time you can figure out a way to make the most complex ratsnest work, trust me I've done a few where it looks so complex it just increases the cool factor 10x because its less random looking and look very fresh
19  Using Arduino / General Electronics / Re: Is arduino equiped with AC protection? on: December 30, 2012, 02:01:57 pm
If you have just a 1M resistor you could get away with using the internal protection diodes and directly hook it up to your source, now this is just technically and no one really like to do this, your best off with using external clipping diodes to protect from >5v and <0v
There will also be resistors involved and the values and wattage of the external diodes will vary depending on your needed frequency response
20  Using Arduino / General Electronics / Re: Op amp output as digital input on: December 30, 2012, 01:53:06 pm
Depends on the opamp, if the 5v is coming from an arduino output you may fry the arduino pin first, depends onthe actual opamp, you couldn't go wrong with a 220 -1kohm resistor in between, you'll never have a problem then so long as the opamp doesn't go above 5v, and then a 5.1v zener would fix that
21  Using Arduino / General Electronics / Re: I want (More than 100% effcient) some LED's! on: December 30, 2012, 12:23:01 am
lumens isnt a very good measure of output since it is a measure of how human eyes can see it, so something that small would probably be less than a lumen, but for example look at infrared leds, they are measured in the same way since you cant see the infrared so technicaly you can have a 10W infrared-led and feel the heat a foot away and yet it will be outputting <1lumen
22  Using Arduino / General Electronics / Re: Zener vs. Voltage divider on: December 29, 2012, 03:15:18 pm
Taking a quick glance at that page you need to level shift not supply power, you should either drop your vcc to 3.3v(easiest) or lookup proper level translators(needed for speed), or find proper zeners that can handle the speed
23  Using Arduino / General Electronics / Re: Charging Arduino-compatible battery wirelessly on: December 27, 2012, 02:13:26 pm
It would depend on whih arduino, at watever voltage you are using, and I'm sure you will need some modifiation regardless of what you find
24  Using Arduino / General Electronics / Re: Variable Voltage Regulator on: December 25, 2012, 01:47:01 am
I can't give you a shematic, right now anyway I'm on my phone, but yes a 10-12v supply would be neccesary although you could probably get away with a small booster circuit if the input impedance of the ballast is small
But the circuit will be a simple transistor switching the 10v supply and passing that thru a lowpass filter
25  Using Arduino / Microcontrollers / Re: good source for ribbon cables w/connectors? on: December 25, 2012, 01:42:04 am
How do those work? I've seen it in radio shack but never been tempted to buy
26  Using Arduino / Project Guidance / Re: Use an Arduino UNO as a USB-to-Serial converter. on: December 24, 2012, 06:55:20 pm
Swap the rx and tx, since the labeled rx and tx is of the 328p not the atmega8/16u2
So put rx of the arduino to rx of the board and same with tx and it will work
27  Using Arduino / Microcontrollers / Re: good source for ribbon cables w/connectors? on: December 24, 2012, 05:41:13 pm
Its for an lcd screen that came with 16 pin single row headers, so I designed it on my board to be the same, in hindsight I coulda done a 16x2 on my board and have the others as grounds which would help keep out interference, right now I'm using just half of a 16x2 cable but its not long enough for my application, just good for testing right now
28  Using Arduino / Microcontrollers / Re: good source for ribbon cables w/connectors? on: December 24, 2012, 05:25:55 pm
Hmm yeah I searched ebay and did not find the same type of connector in 16pin single row, however I found 8pin straight "dp" style cable/connector so I will just use two of those for now
29  Using Arduino / General Electronics / Re: sound like a burnt chip? on: December 24, 2012, 05:23:42 pm
Well that fixed it! Apparently the multimeter was just enough pressure to make contact somewhere, but it works fine all the time now without any pressure applied, and yeah hot air works perfect for small stuff with like soic8 and 0805,1206 stuff but for the 32tqfp it just didn't work out as well, lesson learned
And lol ill be one of those who swear by it because it just worked lol
30  Using Arduino / Microcontrollers / Re: good source for ribbon cables w/connectors? on: December 24, 2012, 01:42:31 pm
That's exactly what I'm looking for , I just need to find it in a 16pin straight version lol, last time I needed one I ended up buying 4 4pin female,female jumpers which works but isn't that legit
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