fluks
August 17, 2022, 5:20am
1
hello all can you guys help me, to convert float to string? I will show the program below, thank you
#include <PZEM004Tv30.h>
#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);
float V1;
float C2;
float F3;
#if !defined(PZEM_RX_PIN) && !defined(PZEM_TX_PIN) //Arduino
#define PZEM_RX_PIN 2 // Pin 2 Rx Arduino ke Pin Tx Pzem
#define PZEM_TX_PIN 3 // Pin 3 Tx Arduino ke Pin Rx Pzem
#endif
#define RELAY_1 4
SoftwareSerial pzemSWSerial(PZEM_RX_PIN, PZEM_TX_PIN);
PZEM004Tv30 pzem(pzemSWSerial);
void setup() {
Serial.begin(115200);
pinMode(RELAY_1, OUTPUT); //Relay
lcd.init(); // initialize the lcd
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("anjai mabar");
delay(1000);
lcd.clear();
}
void loop(){
Serial.print("Custom Address:");
Serial.println(pzem.readAddress(), HEX);
float voltage = pzem.voltage();
if (!isnan(voltage)){
V1 = voltage;
Serial.print("Tegangan");Serial.print(V1);Serial.println("V");
}else{
V1 = 0.0;
Serial.print("Tegangan");Serial.print(V1);Serial.println("V");
}
lcd.setCursor(0,1);lcd.print("Tegangan : ");
lcd.setCursor(10,1);lcd.print(V1);
lcd.setCursor(17,1);lcd.print("V");
if(V1 < 200)
{
digitalWrite(4, LOW);
lcd.setCursor(0,1);
}else if (V1 > 201){
digitalWrite(4, HIGH);
}
float current = pzem.current();
if (!isnan(current)){
C2 = current;
Serial.print("Arus");Serial.print(C2);Serial.println("A");
}else{
C2 = 0.0;
Serial.print("Arus");Serial.print(C2);Serial.println("A");
}
lcd.setCursor(0,2);lcd.print("Arus : ");
lcd.setCursor(10,2);lcd.print(C2);
lcd.setCursor(17,2);lcd.print("A");
float frequency = pzem.frequency();
if (!isnan(frequency)){
F3 = frequency;
Serial.print("Frekuensi");Serial.print(F3);Serial.println("Hz");
}else{
F3 = 0.0;
Serial.print("Frekuensi");Serial.print(F3);Serial.println("Hz");
}
lcd.setCursor(0,3);lcd.print("Frekuensi: ");
lcd.setCursor(10,3);lcd.print(F3);
lcd.setCursor(17,3); lcd.print("Hz");
Serial.println();
delay(2000);
}
J-M-L
August 17, 2022, 5:47am
2
You can Use the dtostr() function to convert your float to its ASCII decimal representation
But the real question is why do you need it at all?
This can be simplified to:
V1 = pzem.voltage();
if (isnan(V1))
V1 = 0.0 ;
Serial.print("Tegangan");
Serial.print(V1);
Serial.println("V");
Similar for current and frequency.
fluks
August 17, 2022, 12:53pm
5
how to make lcd not display last data from pzem? if the source is removed? current position if the source is removed, then the arduino needs to be reset to display the number 0.
PaulRB
August 17, 2022, 1:07pm
6
Follow the advice from @J-M-L . The second parameter of dtostrf() sets the minimum field width for the number. Using that will ensure that any previous data is always completely overwritten with the new data.
fluks
August 17, 2022, 1:08pm
7
do you have any reference about dtostrf()? I'm having trouble making the program
If you have to reset the Arduino to get it to display zero then it sounds like pzem.voltage(), pzem.current(), and pzem.frequency() are not returning. That sounds like a problem in the library. You may have to change the library to implement a timeout is no data arrives from the serial connection.
PaulRB
August 17, 2022, 1:18pm
11
Maybe it's just a formatting problem on the LCD.
Example: if the voltage is 123.45, the LCD shows
123.45V
but then the sensor is disconnected, so the function returns NaN which is replaced with 0.00 and the display then updates to
0.00V5V
Resetting the Arduino would fix this because LCD.begin() probably clears all the text from the LCD.
Oh. If that's what they mean then just write spaces over the field:
lcd.setCursor(0,1); lcd.print("Tegangan : ");
lcd.setCursor(10,1); lcd.print(" ");
lcd.setCursor(10,1); lcd.print(V1);
lcd.setCursor(17,1); lcd.print("V");
PaulRB
August 17, 2022, 1:28pm
13
Yes, that would work, but might also cause some flickering. Using dtostrf() would not flicker and would also ensure that the "." remains in the same place for every value.
fluks
August 17, 2022, 1:47pm
14
is this how to use the dtostrf() function?
char chr[8];
void setup() {
}
void loop(){
V1 = pzem.voltage();
if (isnan(V1))
V1 = 0.0 ;
Serial.print("Tegangan");
Serial.print(V1);
Serial.println("V");
dtostrf(V1, 7, 3, chr);
}
Yes, but it won't be much help until you change: lcd.setCursor(10,1);lcd.print(V1); lcd.setCursor(10,1);lcd.print(chr);
fluks
August 17, 2022, 2:53pm
16
it works, and you know that I haven't changed V1 to chr. thanks
fluks
August 17, 2022, 3:12pm
17
I've tried using the dtosrf() function, but why is it only the voltage that returns to 0? for current and frequency still display the last data?
fluks
August 17, 2022, 3:22pm
18
V1 = pzem.voltage();
if (isnan(V1))
V1 = 0.0 ;
Serial.print("Tegangan");
Serial.print(V1);
Serial.println("V");
dtostrf(V1, 5, 2, chr1);
lcd.setCursor(0,1);lcd.print("Tegangan : ");
lcd.setCursor(10,1);lcd.print(chr1);
lcd.setCursor(17,1);lcd.print("V");
C2 = pzem.current();
if (isnan(C2))
C2 = 0.0 ;
Serial.print("Arus :");
Serial.print(C2);
Serial.println("A");
dtostrf(C2, 6, 2, chr1);
lcd.setCursor(0,2);lcd.print("Arus : ");
lcd.setCursor(10,2);lcd.print(chr1);
lcd.setCursor(17,2);lcd.print("A");
F3 = pzem.frequency();
if (isnan(F3))
F3 = 0.0 ;
Serial.print("Frekuensi:");
Serial.print(F3);
Serial.println("Hz");
dtostrf(F3, 6, 2, chr1);
lcd.setCursor(0,3);lcd.print("Frekuensi: ");
lcd.setCursor(10,3);lcd.print(chr1);
lcd.setCursor(17,3); lcd.print("Hz");
Did you forget to use dtostrf() in all the other LCD output?
fluks
August 17, 2022, 3:37pm
20
it seems not, or is it true that the current and frequency can't be 0 when the source is unplugged?
PaulRB
August 17, 2022, 4:32pm
21
We don't know enough about your project to be able to answer that.
Is chr1 long enough to hold the values of C2 and F3? Maybe try increasing the length of chr1.
As an example, if F3 == 30000 Hz then
dtostrf(F3, 6, 2, chr1);
will not work because only 3 digits are allowed to the left of the "."