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1096  Using Arduino / General Electronics / Re: LEONARDO - DS1307 RTC module need help (NEWBIE) on: February 15, 2014, 12:14:21 pm
You mean it doesn't even say that the RTC isn't running?- might like to check that baud rate...
1097  Community / Website and Forum / Re: What's this # crap in my arduino.cc urls? on: February 15, 2014, 10:44:15 am
As i expected, wikipedia confirms.
It is a fragment identifier, and should scroll to a section of the page linked to, instead of going to the top of that page.
I have no idea how to invoke this or how to prevent it.
So i can't have your browser go to that part of the wikipedia site and you'll have to scroll down a bit.


That was my first thought, but it's different every time I link to the same page, so nope, I don't think that's what it is. And a fragment identifier appears in the mouse-over url in the bottom of the screen; this doesn't.

Now it's:

Quote

..... and actually changes if I just stay on that page and hit refresh.



1098  Using Arduino / Programming Questions / Re: Calculating resistance with Arduino on: February 15, 2014, 10:27:49 am
Paul's equation is wrong since he misread the equation in Wikipedia.

Tbird, your equation in your pic correctly solves for R1.
1099  Using Arduino / Project Guidance / Re: What to keep on hand? on: February 15, 2014, 10:22:17 am
Problem with those little PP3 batteries is not necessarily the current they can provide, but that they can't provide it for very long. Battery capacity is measured in, for instance, mAh (milliAmp x hours) which is a measure of its energy rather than its power. They run flat pretty drastically.

(Power is volts x current, so for a given voltage, current is a proxy for power. Energy is power x time, so if current is a proxy for power, then current x time is a proxy for energy. )
1100  Using Arduino / Programming Questions / Re: Calculating resistance with Arduino on: February 15, 2014, 10:13:11 am
Wikipedia gives a formula for two resistors:
Vout = Z2/(Z2+Z1) - Vin

Vout = Z2/(Z2+Z1) x Vin

1101  Using Arduino / Project Guidance / Re: Current Draw with two seperate power supplies on: February 15, 2014, 09:48:57 am
Ok well, if....

Quote
I left the resistors out the diagram because I was too lazy to add them

.... don't be surprised when other members are too lazy to respond.

1102  Community / Website and Forum / What's this # crap in my arduino.cc urls? on: February 15, 2014, 09:37:19 am
I'm pretty sure this is new, and doesn't seem to happen on other sites, but when I follow a link to anywhere on the site I get some arbitrary junk after a # at the end of the url I've linked to.

For instance, when I hover over the link to setup() on the reference page, it shows bottom left of my screen that I'm destined for

Quote


When I get there, the url box thing displays that for a moment and then changes to (as an example):

Quote

If I do it a few times, that # thing is different, and I got these over the course of a few minutes:

Quote

Anyone know what this is all about and if it's cause for concern? I'm certain it's new, since I often go to pages and copy paste their urls into my replies here and have never seen that before.

Jim
1103  Using Arduino / Project Guidance / Re: Current Draw with two seperate power supplies on: February 15, 2014, 09:25:41 am
Couple of observations, then:

  • You need to hook the ground shown to the Arduino ground, else (for example) the output from the pots' wipers will have no meaning. A bit like imagining the sound of one hand clapping
  • Do you mean the LEDs to be on all the time?- if you intend to control them from Arduino there will need to be some switching mechanism like a transistor whose base is connected to an Arduino digital pin
  • You'll need a resistor on one side of the button as a pull-up or pull-down (or use the internal pull-up via code) else when it's closed you'll short 5v to ground. Have a look at the circuit and sketch here
1104  Using Arduino / Project Guidance / Re: how do I call a sketch from within a sketch on: February 15, 2014, 08:34:15 am
You already have this running over here
1105  Using Arduino / Displays / Re: No works Keypas LCD Shield for Arduino UNO rv3 on: February 15, 2014, 07:12:35 am
Hmm, glad I peeked at this thread, because I had missed the pin 10 thing. My DFR shield shows ~0.6V on pin 10 with the diode test so I guess I'll need to fix that.

For the record, @OP, I've been using LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
1106  Using Arduino / Project Guidance / Re: Current Draw with two seperate power supplies on: February 15, 2014, 06:20:38 am
hopefully the pins should not exceed the current draw from the USB power supply because they are only receiving voltage from the pots and buttons.

I don't understand what that means.
1107  Using Arduino / General Electronics / Re: Convert analog voltage to digital, above certain voltage threshold with passives on: February 15, 2014, 02:39:45 am
Is there some code involved?  Must be, assuming this is some kind of Arduino issue, although you didn't say.

You might be able to sort this out in software....
1108  Using Arduino / Project Guidance / Re: What to keep on hand? on: February 15, 2014, 12:13:23 am
Not that I have one, but something like this may be handy.

I do have one of these.
1109  Using Arduino / Project Guidance / Re: Arduino in automotive? on: February 13, 2014, 10:12:26 pm
I can't speak for the suitability of an Arduino for that but I'm curious as to why you want to do it. If I understand you, you want to delay fuel injection until almost at the top of the compression stroke? Assuming it's technically possible, what advantages do you see?

Traditionally, the fuel was in the air as it's sucked in, since the carburettor relied on the air flow to drop the pressure in the venturi to get the fuel into the air. I suppose it doesn't matter where in the input/compression strokes the fuel is added to the air, as long as it's all in before ignition?  But maybe it does matter.... mixing for example. If you inject fuel just before tdc on the compression stroke, will you get a good mix of the fuel into the air for a good burn?

Can the injector actually inject against that pressure by the way?
1110  Using Arduino / Programming Questions / Re: (5) LM35dz temp sensors to analog pin(s) - uno sketch on: February 13, 2014, 01:27:29 pm
It dawned on me after I posted  my last comments that I have 10 sensors in my stash so I have replaced 2 and now have a closer set of temps.  +/- .75 degrees which is acceptable for my project.


But how do you know any of them are right? Just because they're close....
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