Sorry, not drawn it up yet...
Its a very basic circuit, hence reason not drawn it up, its basically the same from the other day.
Except the one one board is usb powered the other 5v powered from a 9v battery.
So will link the grounds together tomorrow and try again.
I don't like the sound of that at all from the point of view of the current capacity of the battery if it is a PP3 type as illustrated in post #148
Using a PP3 to power the breadboard power supply makes things worse if anything
I'm not really an electronics engineer but looking at the voltage divider, can it be that the impedance of your circuit is too high?
Oh...
So how can i power things
Those two wires went off to a 10k pot, removed after photo was taken as was checking pin spacing
Oh - didnt spot that earlier
Thanks
A 5V 'phone charger would be a good start
Ok, just thought the 9v would have less noise produced
I can usb power the second board from a phone charger, i got a spare one lying about, so just use common the ground ground?
A battery will have less noise (none) but if it can't supply the required current at the required voltage then noise is not going to make any difference
whilst i resolve the issue and find the correct USB lead to power the unit, linked the ground out from one board to the other and resolved the issue - the LCD and Serial Monitor are now displaying the same reading 374 - with 1.154vdc on the input pin A0 but the display is saying 1.83vdc (5/1023x374)
Ok rooky error not common ground between units. So more stable
Great. Now change back to lcd.print(T); to display the temp
lcd.print("Temp = ");
// lcd.print(T);
lcd.print(Vo); // Changed to display input on Analogue Input Pin A0
Serial.println(sensorValue);
So we got something wrong as we have a negative value -31.98 with Serial Monitor saying 392...
But some progress is better than no progress.
So this must be a maths issue now
Where did you get the formula?
T = (1.0 / (c1 + c2*logR2 + c3*logR2*logR2*logR2));
FOUND IT
Your coefficients need to come from the table on page 4
OK well i cocked that up, now got a negative value -311.70
/*
16x1 LCD display using hd44780.h (Hitachi HD44780 driver).
The circuit:
* LCD RS pin to digital pin 12
* LCD Enable pin to digital pin 11
* LCD R/W pin to ground
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* GND to LCD VO pin (pin 3)
*/
// include the library code:
#include <hd44780.h>
#include <hd44780ioClass/hd44780_pinIO.h> // Arduino pin i/o class header
// Sets the pins to be used by the LCD
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
hd44780_pinIO lcd(rs, en, d4, d5, d6, d7);
const int LCD_COLS = 8; // this must be left at 8 for the 16x1 LCD being used.
const int LCD_ROWS = 2;
int sensorPin = A0; // select the input pin for the potentiometer
int sensorValue = 0; // variable to store the value coming from the sensor
// Thermistor Setup
int ThermistorPin = 0; // Changed to A0 from A8
int Vo;
float R1 = 100000; // changed to 100K
float logR2, R2, T;
float c1 = 3.354016e-03, c2 = 2.460382e-04, c3 = 3.405377e-06; // 100K NTCLE100E3 Vishay Thermistor A1, B1 & C1 values
void setup()
{
lcd.begin(LCD_COLS, LCD_ROWS); // initialize LCD with number of columns and rows:
Serial.begin(9600); // initialize the serial communications
// noLineWrap() can be used to disable automatic line wrapping.
lcd.lineWrap(); // turn on automatic line wrapping
// Print a message to the LCD
lcd.print("Let Us Begin!");
delay(2000); // 2 second delay
}
void loop()
{
lcd.clear(); // Clear Screen of existing data
Vo = analogRead(ThermistorPin); // Thermistor Settings
sensorValue = analogRead(sensorPin); // read the value from the sensor:
R2 = R1 * (1023.0 / (float)Vo - 1.0); // 100k x (1023/ 392 -1.0) = 160,969.3878
logR2 = log(R2);
T = (1.0 / (c1 + c2*logR2 + c3*logR2*logR2*logR2));
T = T - 273.15; // Temp in Kelvin
T = (T * 9.0)/ 5.0 + 32.0;
lcd.print("Temp = ");
lcd.print(T);
// lcd.print(Vo); // Changed to display input on Analogue Input Pin A0
Serial.println(sensorValue);
delay(500);
lcd.clear(); // Clear Screen of existing data
}
Try K-1(B1) K-2(C1) K-3(D1) values. I'm grasping now
Try this code. It prints in the serial monitor, not the LCD
//Thermometer with thermistor
/*thermistor parameters:
* RT0: 100 000 Ω
* B: 4190 K +- 0.75%
* T0: 25 C
* +- 5%
*/
//These values are in the datasheet
#define RT0 100000 // Ω
#define B 4190 // K
//--------------------------------------
#define VCC 5 //Supply voltage
#define R 100000 //R=100KΩ
//Variables
float RT, VR, ln, TX, T0, VRT;
void setup() {
Serial.begin(9600);
T0 = 25 + 273.15; //Temperature T0 from datasheet, conversion from Celsius to kelvin
}
void loop() {
VRT = analogRead(A0); //Acquisition analog value of VRT
VRT = (5.00 / 1023.00) * VRT; //Conversion to voltage
VR = VCC - VRT;
RT = VRT / (VR / R); //Resistance of RT
ln = log(RT / RT0);
TX = (1 / ((ln / B) + (1 / T0))); //Temperature from thermistor
TX = TX - 273.15; //Conversion to Celsius
Serial.print("Temperature:");
Serial.print("\ ");
Serial.print(TX);
Serial.print("C\ \ ");
Serial.print(TX + 273.15); //Conversion to Kelvin
Serial.print("K\ \ ");
Serial.print((TX * 1.8) + 32); //Conversion to Fahrenheit
Serial.println("F");
delay(500);
}