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121  Using Arduino / Programming Questions / Re: ionisiation? on: December 06, 2012, 12:59:20 pm
Quote
I really don't think you need an op amp for this. The Arduino pins have very high input resistance (around 100 Mohms), so detecting the difference between 1.7Mohms and infinity is easy. I used a voltage divider made from two 4.7Mohm resistors with an atmega328p in a recent project. However, you will need to take precautions against picking up interference. I suggest you connect your ionisation probe between the input pin and ground, use a 4.7Mohm pullup resistor to +5V, and also connect a 0.1uF capacitor between the input pin and ground.
i did try this but did not seem to work


Quote
You can get finer control by putting fixed resistors in the top and bottom of the pot so the wiper covers a smaller of voltages. Also try reducing the gain a bit

 i haven't altered the gain at all, i presume to lower the gain i reduce the value size of the 100k which is connected to the output of the op amp?
right i think i've got it working in a matter of speaking with out altering the gain the problem i have now is it seems to be too sensitive still so putting my finger between the probes is enough to activate it.
122  Using Arduino / Programming Questions / Re: ionisiation? on: December 01, 2012, 01:04:27 pm
right i tried that and it didnt seem to work when adjusting the pot it just seemed to be all the way one way or all the way the other. i dont know if i need a higher rotation pot so i can be more accurate with it? im currently using something like a 300 degree at the moment
123  Using Arduino / Programming Questions / Re: ionisiation? on: November 24, 2012, 04:48:26 pm
ok cool i got it now thanks, will have to get some resistors in and have a play
124  Using Arduino / Programming Questions / Re: ionisiation? on: November 24, 2012, 04:30:42 pm
like that?
125  Using Arduino / Programming Questions / Re: ionisiation? on: November 23, 2012, 05:01:06 pm
thanks for the reply i am using a LM358 as this is what i had lying around.
ok can you draw that as this is all a bit now to my and will be easier to understand thanks
126  Using Arduino / Programming Questions / Re: ionisiation? on: November 23, 2012, 11:04:32 am
ok thanks for that i have had a bit of a play and come up with this
http://s906.photobucket.com/albums/ac270/Joes-110/?action=view&current=Untitled.png
but now we have gone to the other way now it is to sensitive and can not seem to dye down any idea?
127  Using Arduino / Programming Questions / Re: ionisiation? on: November 21, 2012, 12:40:18 pm
sorry to bring this back up again i had got this working but its extremely unstable as there is not much movement on the arduino, i was using 1500k resistor to even get it to work i cant seem to add any more than that or it seems to go the other way so i dont know how else we could make this work more reliably and give us more of a range on the arduino
i measured the resistance of the probe and flame was 1400k and my supply voltage i was running 17.11 and im getting back on the other end 1.65V so hell of a drop?
128  Using Arduino / General Electronics / Re: From 24V to 5V DC voltage regulator on: September 17, 2012, 10:41:39 am
i'm using a 7805 in one of my circuits and im getting interference issues i havent exactly been able to put my finger on it yet but could it be an advantage changing my regulator for something like this?
http://uk.farnell.com/xp-power/sr05s05/switching-regulator-5v-0-5a-o-p/dp/1861084

not cheap tho
129  Using Arduino / General Electronics / Re: smooth 0-10v output on: September 15, 2012, 04:49:43 am
on that he is using a LM324 i dont need 4 lost of it, just 2 so will this be fine?
http://uk.rs-online.com/web/p/operational-amplifiers/0463145/
130  Using Arduino / General Electronics / Re: smooth 0-10v output on: September 14, 2012, 04:01:54 pm
thanks  smiley-lol
131  Using Arduino / General Electronics / smooth 0-10v output on: September 14, 2012, 03:36:39 pm
hi there im trying to convert my 0-5v pwm output of the arduino to a smooth 0-10v for a high frequency flourescent i come across this just wanted to make sure that this would work or if people have got better suggestions?

http://aartsite.nl/licht/o_5vhrfi.htm
132  Using Arduino / Project Guidance / Re: stepper motor control on: September 11, 2012, 04:09:05 pm
no just runs one way and when button go's high then go's the other way
but thinking about it, the code is runing over and over so it will keep doing it?
so to shop this i have to do somthing like this?

Code:
int ledPin =  13;    // LED connected to digital pin 13
int button = 2;      // button pin

int count = 0;       // Our blink counter

// The setup() method runs once, when the sketch starts

void setup()   {               
  // initialize the digital pin as an output:
  pinMode(ledPin, OUTPUT);
  pinMode(button, INPUT); 
}

// the loop() method runs over and over again,
// as long as the Arduino has power

void loop()                   
{
  if (digitalRead(button)== HIGH)  // buttin when high
  {
  if (count < 1) {
    digitalWrite(ledPin, HIGH);   // set the LED on
    delay(1000);                  // wait for a second
    digitalWrite(ledPin, LOW);    // set the LED off
    delay(1000);  // wait for a second
   
    count++;  // add one (1) to our count
  }
  }
  else {
    if(count == 1) count =0;       // resetting the count
  }
}
133  Using Arduino / Project Guidance / Re: stepper motor control on: September 11, 2012, 03:01:00 pm
thanks for that but when button if high the stepper funs continuosly in the one direction
134  Using Arduino / Project Guidance / stepper motor control on: September 10, 2012, 03:19:22 pm
hi there i have made this code up,i would like to add another function, when a switch pin goes high the stepper will return to its 0 position and when the pin goes low the stepper will return the where the pot is set to. how do we do this?

Code:

#include <Stepper.h>

// change this to the number of steps on your motor
#define STEPS 100

Stepper stepper(STEPS, 8, 9, 10, 11);

// the previous reading from the analog input
int previous = 0;

void setup()
{
  // set the speed of the motor to 30 RPMs
  stepper.setSpeed(150);
}

void loop()
{
  // get the sensor value
  int potVal = analogRead(0);
  int stpPos = map(potVal, 0, 1023, 0, 100);

  stepper.step(stpPos - previous);

  // remember the previous value of the sensor
  previous = stpPos;
}
135  Using Arduino / Project Guidance / Re: variating an ouput over time on: September 09, 2012, 01:36:43 pm
thanks johnwasser for that can you explain what is going on in it?
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