My old logitech speaker broke, but the wall wart from still seems to work. The plug fits the arduino voltage in port, but it is 6V @ 1.2A. Is this okay?
Here's a pic:
(sorry its big)
Thanks in advance.
Assuming you have a duemilanove, the schematic shows the regulator as
MC33269D-5.0
The lowest voltage difference I see between Vout & Vin is 1.35V to maintain the spec'ed % regulation. Below that, who knows?
If you had a separate regulator chip, you could prototype the minimal regulator circtuit (just a couple of caps) and experiment with different loads and see what you get.
The Uno looks to have the same regulator spec'ed - with a 2nd MC33269ST-5.0T3 in parallel.
Same limit.
Its negative centre polarity which means it won't work on the arduino. 6v isn't enough for the voltage regulator, but they frequently kick a lot more than what they say on the label.
So, no basically.
But what if I cut the wire? (The original user (the speaker) is long gone)
If you swap the pin polarity... you have a slight chance of that wall-wart being useful... but as already stated... 6V is really close to the drop out voltage of a 5 volt regulator.
For example: this wall-wart would absolutely not work on my home built Severino that uses a 7805 5 volt regulator.
I'd try it anyway since I see a lot less center-nagative these days so your power supply will probably not find a second life with way a wireless router. Just cut it, find which lead is positive and ground, mark with two masking tapes on the wires, check the voltage with a multimeter. If it's more than 6V, give it a try, plug into the arduino gnd and vin pins. If arduino powers up, you just saved yourself a few bucks and a trip to a thrift store.
This thing may come in handy once you know it works:
I just found this:
http://azsurplus.com/index.php?main_page=product_info&cPath=1_14&products_id=1334
In my basement. It fits, too.
Better choice.
Your power adapter could still be useful. You could wire the positive to one or two series diodes and power via +5vdc directly, bypassing any on-board +5vdc regulator. Each diode should 'drop' about .6vdc. Also +6vdc is nice for externally powering r/c type servos.
I just hooked up both wall warts to my old analog multi. The Kodak 7V one seems to not be rectified The needle peaked at about 7V, but then fell to 3V, and back up again. The speaker's 6V wall wart output an even 6V.
The speaker one outputs a clean, consistent 6.18V DC @ 700mA, but it is not enough. Help!
P.S. I blew my half amp fuse on the 2amp kodak wall wart...
What is connected to your Arduino? There is no way the Arduino by itself drew 1/2A.
It was not connected to my arduino. I connected the wall wart directly to my multi.
How about this:
Since the 6.2V wall wart is the wrong polarity, I cut wires, flip them, and resolder them. Then I can plug into the Arduino?
If its the right polarity it shouldn't damage anything, it might not have the full 5v on the 5v rail though. Suck it and see.
Arduino is center-positive, so if multi reads +6.18VDC when red probe is inside jack and black probe is touching outside, I am good?
Yep. Just tested it. w/ USB, 5V is 5.03VDC. with jack, it is 4.49VDC. Okayish, but not the best.
k. Maybe i'll just buy the 9V wall wart from sfun when it comes in stock.
Would a nine volt battery work? I have lots.
Ok. I'll just buy a new wall wart.