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361  Using Arduino / Project Guidance / Re: Turning off a high voltage circuit with D3, HIGH on: May 10, 2014, 09:27:36 pm
Yeah, I can pull enough current to light a red LED,
Through what? From where?
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so that's got to be close to  150mA.
A standard red LED will shine quite brightly on 1/10th of that and melt on 1/5th of that.
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I was thinking an NPN transistor for the switch control. I'm trying to learn more about them. The trigger uses a simple push button, similar to the Arduino Uno reset button. I think I could patch my transistor between the push button and the motor.
Pictures and diagrams would help.
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I'm waiting for the carbon brush to arrive by mail,
We're all waiting on some definite information, so that we don't have to guess what you're trying to do.
362  Community / Exhibition / Gallery / Re: Blink without "delay()" - stepping up. on: May 09, 2014, 09:43:05 pm
Instead of:
Code:
 // Act if the latter time (ms) has now passed on this particular counter,
  if (timeout(&count1, 500UL )) {
    if (led1State == LOW) {
      led1State = HIGH;
    }
    else {
      led1State = LOW;
    }
    digitalWrite(led1Pin, led1State);
  }
I'd use:
Code:
if (timeout(&count1, 500UL )) { //has the timing period ended?
 led1State = !led1State;//Invert Led1State, HIGH becomes LOW and LOW becomes HIGH.
 digitalWrite(led1Pin, led1State);//turn LED on or off, as defined by led1State.
  }

I'd also add an explanation that, although this code only blinks LEDs, the principle can be use to time anything.
363  Community / Bar Sport / Re: This community sucks on: May 09, 2014, 08:45:13 pm
Go up one forum and find this page.
That was started yesterday, and finished today in a link to a $ 50,- indigogo project.
I'm not interested in it or any other of his projects, certainly not after OP's rant today (which wasn't the first time i saw comments like this from him).
As there are no answers to the aforementioned thread, and one comment that seems to be invisible on indigogo, there's no way of telling what set OP to his ranting rampage.
It appears that his rage was caused by there being no answers to his thread. The poor thing doesn't like being ignored. He should get over it.
364  Community / Bar Sport / Re: Post your code on: May 09, 2014, 08:14:31 pm
Suggest making a sticky out of wildbill's post, with Grumpy Mike's 2nd recording.
If we do that, they'll be demanding royalties.    smiley-money
365  Community / Bar Sport / Re: Post your code on: May 08, 2014, 11:41:30 pm
Having read one too many post today where this would have been handy, and following in the foorsteps of write in C. I give you, post your code:
Excellent, Wildbill, but I do have a suggestion for one verse.

The weeja board has failed us,
and the crystal ball's in overload.
There will be an answer, post your code....

The seers have all left this place,
and they've taken to the open road.
Whisper words of wisdom, post your code...
366  Community / Bar Sport / Re: Post your code on: May 08, 2014, 10:52:11 pm
OK - finally got round to doing a remix, hope you find it better.
Better on the balance, Mike, but the 'middle 8' was still the best bit.  smiley-grin
367  Using Arduino / Project Guidance / Re: Problem powering a Yun and a Mega on: May 08, 2014, 08:44:01 pm
I am working on a home automation project in which I have a Mega (2560) and a Yun.  I am powering the Mega USB input from a Kara Mobile regulated switching 5v supply with a hacked USB cable (+/- 5v only - no data).  I saw no discussion about the USB shield so I also connected the hacked USB cable connector shield/shell to the minus 5v line of the supply.  All seems OK to this point.  I  powered the Yun “Vin” from the Mega’s 5 volt buss.  This also seems to work OK but my problem is the large amount of current the Yun will be pulling and hence total power coming into the Mega. 
It seems that I could create 2 hacked USB cables in parallel on the regulated supply output to separately feed the two controllers.  Question: if doing this, should the the USB connector shield/shell be connected to the supply minus 5 volt line in both hacked cables?  Should there also be an additional ground between the Yun and Mega, since I hope to have them communicating in the future?
Alternately, it seems I could directly wire the regulated 5v to the Mega’s 5v buss and also to the “Vin” on the Yun with the Grounds connected together.  However, this would bypass any internal fuse/protection that the USB input would provide.  Any recommendations would be most appreciated.
Thanks.
You also have to remember that a USB 2 port can only output 500mA. Running the two from one port may overload the port. I understand that USB 3 ports (the blue ones) can output 1A.
368  Using Arduino / Project Guidance / Re: Using an Arduino in Vacuum on: May 08, 2014, 08:24:42 pm
The only way to be sure is to draw a vacuum on some examples. If it survives once, it should be good.
The expression that comes to mind is "Suck it and see."    smiley-grin
369  Using Arduino / Project Guidance / Re: Short burst of air / hiss on: May 08, 2014, 08:10:29 pm
Hi,

I'm trying to figure out how to get a short burst of air to be controlled with arduino. I want it to be small and otherwise quiet as possible mechanism, and able to repeat fairly quickly if required. It doesn't need to be super powerful, just enough to make a quick hiss noise. Any ideas? I was thinking maybe some sort of solenoid in a tube with a one-way valve type setup, but not sure if that is the best method or if someone has done something more appropriate?
It's not clear if you need the air or just the sound. If just the sound, you can record it and have the Arduino play it back when needed. If you need the air to blow something you'll also need a compressor or pump of some type and these are not usually very quiet.
370  Using Arduino / Programming Questions / Re: How to use timer??? on: May 07, 2014, 11:41:09 pm
So I'm trying to write a code for a class and it has to take heart rate as the input, and print out on an LCD screen what that rate is (this is the output).  This code is supposed to use a timer and/or a counter, and I have no idea where to begin.  All the examples of the timers I have found use a blinking LED. 
Don't look at what it does, look at how it does it.
371  Using Arduino / Programming Questions / Re: Loop run for period and begin another cycle on: May 07, 2014, 10:58:11 pm
Good evening folks,
Your good wishes are appreciated, but this is a world-wide forum, so your evening is the middle of the night here, afternoon in some places and morning in others.   smiley
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I want to visually see the duty cycle change every 10% on my DC motor. I want to start from 10% and get to 100%. Forgive me if this seems trivial but I am an extreme novice. Here is my sketch so far at a 10% cycle.
I'm not certain what you want, but try this:
Code:
int a;
int z;
void setup (){
  pinMode (2, OUTPUT);
}
void loop (){
  for(z =1; z<10; z++){
     a = z * 50;
     digitalWrite (2, HIGH);
     delay(a);  //no need to use micros when millis will do
     digitalWrite (2, LOW);
     delay (500-a); //duty cycle 10% to 90%
  }
  digitalWrite (2, HIGH);
  delay(500); //duty cycle 100%
  digitalWrite (2, LOW);
}
That should, by my rough calculation, give about a 5 second cycle. To adjust it, just alter all the delays by the same amount and the multiplier to 1/10 of the delay figure (Eg. delay (550-a), delay(550) and the multiplier 55).
372  Using Arduino / Project Guidance / Re: Serial Read at any point in a program? on: May 07, 2014, 10:06:36 pm
Probably, the 'blink without delay' example sketch in the IDE will help you, but without seeing your code I can't be sure. My crystal ball running XP has crashed!
373  Using Arduino / Project Guidance / Re: Breathing LED, PWM - Change duration of breath on: May 07, 2014, 09:58:41 pm
Simple mathematics. A Karma point would be appreciated.
374  Using Arduino / Project Guidance / Re: Can the Arduino do this - power source switch on: May 07, 2014, 09:45:55 pm
Now that makes sense and is doable.
The only real problem seems to be 'I've become quite interested in the Arduino' and am looking forward to doing stuff with it.
I suppose i could do both ?  but for now the grey cells are happily tinkering with the Arduino project, detail and incidental - keeps them perky.
Thanks again for that idea
Sometimes, KISS (keep it simple, stupid) is the only way to go.  smiley
375  Using Arduino / Project Guidance / Re: Turning off a high voltage circuit with D3, HIGH on: May 07, 2014, 09:23:38 pm
I'm using a medical device drill. Used in surgery.
Is this a high speed medical drill? Cutting the power to one of those won't stop it immediately, as there will be some run-on, dependent on friction. Also, if this is to be used in a medical situation, it wouldn't be a good idea to use a carbon brush for contact, as bits of carbon could break off and get into the patient, and a carbon brush probably wouldn't withstand sterilisation.
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The manufacturer has told me is 15v DC and I'm waiting to see if they'll answer my questions regarding current. If they don't tell me, I guess I might have to break it to get a multimeter in there.
Then how do you propose to turn it on and off? As long as you can get to the 15V leads you can measure the current with a meter.
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