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[Reply #195 on:]

((reading / 1024) * 5);

reading is 0 ->1024
therefor reading/1024 will be 1 or less (Probably rounded to 1) * 5 = 5,
what value range are you trying to get?

[Reply #196 on:]

Try to check your LM35 with a multimeter

http://www.ladyada.net/learn/sensors/tmp36.html

[Reply #197 on:]

Thanks for the link to the tmp36 code. I originally used that code and from project to project it has evolved. My issues, for a reason I am not too sure of, stemmed from not using "float". I toyed with code straight from adafruit's page and found that it broke if I did not float my values. Thank you for your help. I am finished with the coding. Because the "arduino tiny" core was so easy to implement I no longer need to embed 328's for simple projects like this. One final question:

Is there an easy way to use the ATtiny85's internal temperature sensor through ArduinoISP?

Here is the current completed code (when I embed this I will remove the "serial" functions).

Code:

const int r = 4;//red
const int b = 0;//blue
const int g = 1;//green
const int s = 1;//sensor *ANALOG

int temp, currentTemp;
int previousTemp=0;

long previousMillisTIME= 0;
unsigned long intervalTIME = 1000;

void setup(){
  Serial.begin(9600);
  pinMode(r, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(b, OUTPUT);
}

void loop(){

  unsigned long currentMillisTIME = millis(); 
  if(currentMillisTIME - previousMillisTIME > intervalTIME) { 
    sense();
    previousMillisTIME = currentMillisTIME;
  }       

  int flick = random(120)+135;//candle like effect

  if (temp < 68){//only show blue
    digitalWrite(r, LOW);
    digitalWrite(g, LOW);
    analogWrite(b, flick);
  }
  else {
    if (temp > 72){//only show red
      digitalWrite(b, LOW);
      digitalWrite(g, LOW);
      analogWrite(r, flick);
    }
    else {//only show green
      digitalWrite(b, LOW);
      digitalWrite(r, LOW);
      analogWrite(g, flick);
    }
  }
  delay(random(150));
}

void sense(){
  delay(10);
  int reading0 = analogRead(s);
  delay(10);
  int reading1 = analogRead(s);
  delay(10);
  int reading2 = analogRead(s);
  delay(10);
  int reading = ((reading0+reading1+reading2)/3);//average readings
  float voltage = reading * 3.3;//voltage reference
  voltage /= 1024.0;
  float temperatureC = (voltage - 0.5) * 100;
  float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
  currentTemp = temperatureF;
 
  if(currentTemp - previousTemp >= 3) {//hysteresis forward
    temp = temperatureF;
    Serial.print("Changed From ");
    Serial.print(previousTemp);
    Serial.print(" to ");
    Serial.println(currentTemp);
    previousTemp = currentTemp;
  }
  else {
    if(currentTemp - previousTemp <= -3) {//hysteresis backward
      temp = temperatureF;
      Serial.print("Changed From ");
      Serial.print(previousTemp);
      Serial.print(" to ");
      Serial.println(currentTemp);
      previousTemp = currentTemp;
    }
  }
    //debugging
  Serial.print(voltage);
  Serial.println(" volts");
  Serial.print(temperatureC);
  Serial.println(" degrees C");
  Serial.print(temperatureF);
  Serial.println(" degrees F");
  Serial.print("current reading ");
  Serial.println(temp);
  Serial.println(" ");
}

[Reply #198 on:]

I'm trying to use the ATtiny85 Arduino Tiny core in a project where I need to use the 2.56v internal reference for the ADC - not least because I need the ARef pin for other things, but also so that the reading is not directly dependent upon VCC, which in a battery powered situation is not very uniform. I appreciate that we need to use the non-decoupled 2.56v to avoid connecting pin 5 to that voltage.

I have tried poking at ADMUX without success and wondered:

Does analogRead always use the external Vref?
If so, can I read ADCL & ADCH directly?  I have tried but seem to be getting zeros.

Any thoughts appreciated.

Edit - it appears that by poking ADMUX I can alter the reference voltage (I can set it so that the 2.5v appears at PB0) but as soon as I call AnalogRead it reverts to the external ref.

[Reply #199 on:]

Huh.  Looks like the coin flip had me pick the wrong one to include...
http://code.google.com/p/arduino-tiny/source/browse/trunk/hardware/tiny/cores/tiny/wiring.h#105

  analogReference( 6 );

...should do the trick.  Do you have a preference for the name of the constant (other than INTERNAL2V56)?

[Reply #200 on:]

That's fantastic - I would not have believed that I could have learned quite so much from such a short reply!

I did have a hunt through the source code for the tiny core but didn't find anytihng, but it would have taken me a while to get around to looking in wiring.h

I suppose INTERNAL2v56NB (for no bypass) is as logical as anything but you will have a much better feel for that than me.  

I do think this is a useful reference to have because, with so few pins, if you want an absolute measurement but are not too worried about accuracy then you might prefer to avoid giving a pin up to a capacitor.

Thanks again

[Reply #201 on:]

unfortunately I'm getting a not in sync error when using these cores when trying to bootload.  resp 0x00

[Reply #202 on:]

unfortunately I'm getting a not in sync error when using these cores when trying to bootload.  resp 0x00

In order to help, you will need to supply some more information.

• What version of the IDE are you using?
• What chip are you attempting to program?
• What device are you using to do the programming?
• Turn on verbose programming and provide a complete copy of the output
• How are you connecting the device to the programmer? Picture helpful.

[Reply #203 on:]

I'm using Arduino IDE 1.0.1
ATtiny45 @ 8
ArduinoISP (Arduino Duemilanove)
I don't know how to turn on verbose programming
Here is a video of the whole deal,  It starts out dark so you can see the TX and RX leds and then it shows my setup

[Reply #204 on:]

Verbose programming can be turned on use File | Preferences

[Reply #205 on:]

Code:

C:\Users\shannon\Desktop\arduino-1.0.1\hardware/tools/avr/bin/avrdude -CC:\Users\shannon\Desktop\arduino-1.0.1\hardware/tools/avr/etc/avrdude.conf -v -v -v -v -pattiny45 -cstk500v1 -P\\.\COM6 -b19200 -e -Uefuse:w:0xFF:m -Uhfuse:w:0xD7:m -Ulfuse:w:0xE2:m

avrdude: Version 5.11, compiled on Sep  2 2011 at 19:38:36
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2009 Joerg Wunsch

         System wide configuration file is "C:\Users\shannon\Desktop\arduino-1.0.1\hardware/tools/avr/etc/avrdude.conf"

         Using Port                    : \\.\COM6
         Using Programmer              : stk500v1
         Overriding Baud Rate          : 19200
avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: Recv:
avrdude: stk500_getsync(): not in sync: resp=0x00

avrdude done.  Thank you.

[Reply #206 on:]

I want to use an attiny84 for some speed/timing stuff at 3v. The internal oscillator is pretty lousy, can I use a 1MHz external crystal? And if so, what pins are for the crystal on the 84?

Thanks

[Reply #207 on:]

The XTAL pins are on physical pins 2 and 3 (PB0 and PB1). You would have to change the boards.txt file to use the correct freqency. There is an entry for 84 with a 16MHz external crystal, just copy and paste this, change the name and set the freqency to 1000000

[Reply #208 on:]

I've noticed that digitalWrite isn't available inside the setup(). Why?

EDIT:
forget about it

[Reply #209 on:]

Code:

for (byte temp = 0; temp++; temp < 4) {

should be:

Code:

for (byte temp = 0; temp < 4;temp++) {