Show Posts
Pages: 1 ... 36 37 [38] 39
556  Using Arduino / Project Guidance / Temp measurement and display on: August 14, 2011, 05:16:43 pm
hi all, just messing around and getting used to the arduino.

I've hooked up a 10k thermistor and got it working using a tutorial to feedback data over serial. I have added too the code to display on my lcd screen. It works but when the temp goes below 10 degrees the display moves the digit over so for example 9 degrees reads 90. It does not display like this on the serial monitor however, but I used the same code to get the data over the display?
Hope that makes sense!

Code:
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);




#include <math.h>

double Thermister(int RawADC) {
 double Temp;
 Temp = log(((10240000/RawADC) - 10000));
 Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
 Temp = Temp - 273.15;            // Convert Kelvin to Celcius

 return Temp;
}

void setup() {
lcd.begin(16, 2);
delay(100);
 Serial.begin(115200);
}





void loop() {
 
      lcd.setCursor(0,0);
lcd.print(int(Thermister(analogRead(0))));
 
  lcd.setCursor(2,0);
  lcd.print((char)223);
 
 
    lcd.setCursor(3,0);
    lcd.print ("c");



 Serial.println(int(Thermister(analogRead(0))));  // display Fahrenheit
 delay(1000);
}

557  Topics / Home Automation and Networked Objects / Re: Time/temperature controller on: August 13, 2011, 09:43:16 pm
looks great! any videos? smiley
558  Using Arduino / General Electronics / Re: Thermistor question on: August 12, 2011, 10:36:26 pm
I see, so really all that would vary would be the current? but still 5v as you say
559  Using Arduino / General Electronics / Thermistor question on: August 12, 2011, 09:31:21 pm
I have just started messing with a 10k thermistor and got a temperature to display on my lcd using the first simple example on this page http://www.arduino.cc/playground/ComponentLib/Thermistor2

is this anymore or less accurate from using the longer examples and/or a look up table?

also, what are the pro's (if any) and cons of not using a voltage divider and just running 5v through the 10k thermistor and measuring what comes out the other side?

how long could the cable to the thermistor be without effecting the resistance too much?

thanks!
560  Using Arduino / Displays / Re: LCD does not work unless Arduino is reset. on: August 12, 2011, 09:07:36 pm
still got the problem with mine, delay does not seem to help, I've even tried up too 10 seconds
561  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 08, 2011, 05:43:31 pm
Hi, yes the lcd lib is the most recent I think, it states the date that you mentioned smiley-sad
562  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 05, 2011, 07:03:29 am
hey mate.

I have tried a delay as the first instance in the set-up, still doesn't work 9 times out of 10. I have even tried up to 10 seconds delay smiley-sad

Is it possible to issue a command for a full reset? so it will reset once on its own? Thinking about it probably not because it will just loop on reset won't it lol.

Do you think it needs something in the library changing?

thanks
563  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 04, 2011, 07:05:21 am
I guess it must be something to do with initial power up, I hope I don't have to have a hardware solution to fix it!

Thanks I will take a look at the links. The thing is we have about 400 of those screens at work, they were given as part payment from a customer, so I have no idea where they came from and it would be really good to be able to get some use out of them so I would like to fathom it out lol.

I tried a delay as the first thing the code runs but no luck smiley-sad

your phi-shields look useful I might have to get one for fiddling at home smiley

Thanks again
564  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 03, 2011, 05:28:24 pm
I think you are right there, i have a same set-up at home (arduino uno, same model lcd) and that is also temperamental with exactly the same fault. I don't have any different LCD's to try I don't think, although I may have a serial display at work that I could possibly look at.

what kind of additions to the code do you have to put in to get your screen to work?

thanks for your time by the way  smiley
565  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 03, 2011, 11:54:29 am
When it first powers up I get solid black along the first line ie. all pixels. 9 times out of 10 it hangs like this until I reset the board, rarely these squares appear for around 1-2 seconds then the code runs.

I have tried powering from 12v dc, and usb both with the same issue?

I am using a 150ohm resistor on the back light to drop from 5v to approx 4v

I have just uploaded a short video, let me know if you can view the format. http://shedbass.net/dtokez/VID_20110803_174424.m4v

thanks again!
566  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 03, 2011, 08:11:25 am
Excellent thanks, |measured Aref to gnd and got a difference of 5.02v so you were bang on smiley

When I measure the 5v line to gnd I get about 4.9v - But I guess its the analoge ref that counts?

One issue I'm having is that sometimes the board does not run when first plugged in, I have to reset. This would be a bit of a pain once its mounted in an enclosure lol
Is there something wrong with the setup in the code?
Here is what I have now..

Code:
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

int analoginput = 0;
int analoginput1 = 1;
int analoginput2 = 2;
float vin = 0.0;
float vin1 = 0.0;
float vin2 = 0.0;

void setup(){
 
 // declaration of pin modes
 lcd.begin(16, 2);
delay(100);


    lcd.setCursor(0, 0);
   lcd.print("REAPsystems V1.1");
       lcd.setCursor(0, 1);
   lcd.print("iSensor tester");
   
   
   delay(4000);
   
   
   
  lcd.clear();

}



void loop(){
 
 
     delay(1400);


 // read the value on analog input
lcd.setCursor(0,0);
lcd.print ("Vin:");
vin = analogRead(analoginput)*5.023/1024*2;
lcd.print(vin, 3);
lcd.setCursor(9,0);
lcd.print ("v");
 
lcd.setCursor(0,1);
lcd.print ("A:");
vin1 = analogRead(analoginput1)*5.023/1024;
lcd.print(vin1, 2);
lcd.setCursor(6,1);
lcd.print ("v");


lcd.setCursor(9,1);
lcd.print ("B:");
vin2 = analogRead(analoginput2)*5.023/1024;
lcd.print(vin2, 2);
lcd.setCursor(15,1);
lcd.print ("v");


delay(1400);

}

Thanks for the help!

567  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 02, 2011, 10:29:40 am
Got it working now thanks  smiley-cool

I did not use 10 ohm resistors though as the current would have been stupid lol silly me!

One thing though, is there a way of calibrating, or is there no real reason why it should not be accurate?

when I place a voltage on one of the inputs, sometimes (more often than not) one of the other inputs rise a little. is this just noise?

I don't really want to decrease the value of the pull down's because someone suggested that its not really that good to have the analogue pulling to gnd

thanks for all the help  smiley
568  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 02, 2011, 09:29:11 am
I need to use a voltage divider I think, and if I used two 10ohm resistors I should get 2.5v from 5v according to my calculations?

The thing I'm confused about is how would I adapt the coding?
569  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 02, 2011, 08:03:13 am
Well I have been experimenting with some values, and it seems to be that the highest resistance I can go to without float is about 300k.

Id rather not pull them at al but its going to be used as test equipment so It needs to be clear if something has a fault or its just the input floating around.

I have also now built the circuit on a proto-sheild (lcd wiring etc) and it seems to be a bit more accurate... about 20mv off so I could probably get away with that smiley might have been picking up some noise or something on the breadboard I guess?

The other thing, input no.1 will be measuring 5v, at the moment my range is 0-5v so I guess it would be more sensible to measure the range of 0-10v so 5v sits in the middle.

Could anyone please advise me on how to achieve this?

Many thanks  smiley-mr-green

570  Using Arduino / Project Guidance / Re: Three voltage measurements + output to a LCD screen on: August 01, 2011, 08:49:33 am
there will not always be an voltage connected to all three inputs, in which case id rather them read 0v than some phantom reading  smiley
got them pulling down now via a 47k resistor and it seems to work nicely

I still have the problem of the measurements being off slightly though smiley-sad is it possible to somehow calibrate it?
Pages: 1 ... 36 37 [38] 39