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16  Using Arduino / Microcontrollers / Re: adding a new chip to uno board on: April 16, 2014, 05:33:30 am
There is maybe a simple reason why this wont work but could you add a duplicate of the ATmega328P to avrdude.conf and alter the id, desc & signature to match the ATmega328.

Yes.

You have gotta do better than that.

Not my fault the question is ambiguous...

Yes it will work. That's what the file is for.

17  Using Arduino / Microcontrollers / Re: adding a new chip to uno board on: April 16, 2014, 03:36:14 am
There is maybe a simple reason why this wont work but could you add a duplicate of the ATmega328P to avrdude.conf and alter the id, desc & signature to match the ATmega328.

Yes.
18  Using Arduino / General Electronics / Re: Powering 45M of LED light strips safely on: April 16, 2014, 02:21:00 am
I mean, if you light them al white you should absorb about 60mA (3 x 20) per LED which seems to be around (60 x 60) 3600mA per meter...

That depends if they're in series or parallel.

"12V" LED strips have the LEDs in groups of 3 so the current requirement is 1/3 of that.

But....we don't know what the LED strips are.
19  Using Arduino / General Electronics / Re: Is it necessary to have both a digital and analog oscilloscope? on: April 15, 2014, 01:32:01 pm
PS: Dave's product test of the Fluke 28-II Multimeter is worth watching:

https://www.youtube.com/watch?v=qlA7-fh5nDQ



20  Using Arduino / General Electronics / Re: valley peak detector on: April 15, 2014, 01:28:24 pm
Hi All,
I am not limited to the first circuit I posted.  It can be a circuit with an op amp, or comparator.

An Op-Amp will invert a signal easily.
21  Using Arduino / General Electronics / Re: Is it necessary to have both a digital and analog oscilloscope? on: April 15, 2014, 01:16:29 pm
Mad Dave Jones... yeah, we've seen him.

I doubt he said you need both types of oscilloscope. I've never seen him using anything analog.

Is this the video you mean? https://www.youtube.com/watch?v=Xh9FNRpta9s

What he's saying there is that if you don't have any money you should buy a second-hand analog scope instead of one of those pocket DSO things off eBay.

The eBay 'scope he tried was this one: https://www.youtube.com/watch?v=3im97Z7ceNI

That one is a pile of garbage, to say the least. There's a different one called a "DSO Quad" which is orders of magnitude better but doesn't cost much more than that one.

OTOH he has a point. "Real" 'scopes have much better controls and internal circuitry. The DSO quad works well enough but the user interface is horrible and the bandwidth is probably below 10MHz despite what the sellers say.

If you're serious about electronics it's worth waiting a bit longer and saving up to get a proper digital scope.
22  Using Arduino / General Electronics / Re: My First Oscillioscope on: April 15, 2014, 08:25:23 am
A rule of thumb is that the bandwidth needs to be 10x the signals you want to look at.

An Arduino can put out an 8MHz signal so you need 80MHz or more to see that properly.

23  Using Arduino / General Electronics / Re: valley peak detector on: April 15, 2014, 03:06:52 am
Hi all,
Any one know how to build a simple valley peak detector using a zener or schottky diode? I can build a peak detector with either fine. But can't seem to get the valleys?

Why not invert the signal and use your peak detector...?

24  Using Arduino / Microcontrollers / Re: ATtiny84 with internal pull-ups on: April 15, 2014, 02:38:18 am
And the current from each io pin to ground is 2.89mA, so I am not overloading the io pins

Agree with fungus, 2.89mA is definitely too high. How about a picture?

Yep. This is the clue. 2.89mA is just wrong.

The problem isn't the code, it's the power supply, the breadboard, something like that.

25  Using Arduino / Microcontrollers / Re: Power Supply to Standalone on: April 15, 2014, 02:36:11 am
building a standalone micro controller for a project, have it working fine with a 5v power supply from spark fun http://www.sparkfun.com/products/8269 in order to make it cheaper to reproduce I want the power regulation to be built in to the circuit board so that i can just wire a cord to be plugged straight into a wall socket. anyone have any links to circuits or general advice? as I'm not really sure where to start at all..

I doubt that will make it cheaper but it will be illegal to sell because it has no FCC/CE approval.

Put in a USB socket instead, USB power is *everywhere*.

Most people will have several USB power supplies at home so you don't need to include one with your device (it doesn't get cheaper than that!) You can offer a version with wall wart as an optional extra.
26  Using Arduino / General Electronics / Re: Is capacitive sensing possible with batteries? on: April 15, 2014, 02:26:22 am
Quote
A piece of foil in the base of the jar works.
What if the foil was replaced with transparent conductive spray?

Would probably work...

27  Using Arduino / General Electronics / Re: Is capacitive sensing possible with batteries? on: April 15, 2014, 02:25:12 am
Check out 'butteryfly in a jar' at youtube. I'm 99% convinced it's a piezo. One guy writes 'spoiler alert - see how it works.' He plays with the butterfly, opens the lid, and shows where the batteies and switch are. And that's it. He shows how it OPERATES but not how it WORKS. So that's yet another 2:43 of my life waste that I'll never get back.  smiley-sad-blue

Another forum there's a buncha discussion the butterfly, capacitance, piezo, and the thread ends where someone writes 'I'll take one apart and let you know.' That was in 2011. [checking sundial [sigh]]

Given $ vs ease of design, piezo is cheap, easy and reliable.

Trouble is... my jar spends a lot of time with the CPU in sleep mode. You have to put your hand on it for a second or so to wake it up via capsense. It would miss a quick tap on a piezo.

28  Using Arduino / General Electronics / Re: is there a difference between dc capacitor and ac capacitor? on: April 15, 2014, 02:20:06 am
i tried it hard with the shopkeeper to know whether the capacitor is y rated but it seems like he just does not know anything about his products. anyways i brought this 100nf 400v capacitor with no polarity marking, will this work?
 image given
model no -100k400

Looks like polyester.

It's unlikely to burn/explode but 600V would be a better choice if he has them.
29  Using Arduino / General Electronics / Re: Uno's analog pins and short circuits on: April 14, 2014, 06:00:41 am
When pins are set as INPUT they have a very high resistance (megaohms).
30  Using Arduino / General Electronics / Re: Powering Ardunio UNO from 9 Volt battery and connecting it to USB on: April 14, 2014, 05:24:21 am
How did you connect the Arduino to the Raspberry Pi?

A battery will work, but I think it should work from the Pi if you have an external supply for the motor.




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