SHT40 Raspberry Pi Pico Arduino Earle Phillhower

[TheLennyLeonard]

Hello, I have a problem with your library in arduino with Earle Phillpower library. I use your SHTSensor library, i think correctly but still not getting responses from SHT40. Can you please help me? (it is correctly wired - power 3,3V, pull up for SDA,SCL - 2,2kOhm resistors)

the SHT40 is connected to
GP14 --> PIN 19 on the Pico
GP15 --> PIN 20 on the Pico
`
#include <Wire.h>
#include "SHTSensor.h"

SHTSensor sht(SHTSensor::SHT4X);

float actualTemperature = 99.9;
float actualHumidity = 99.9;

void setup() {
pinMode(14,INPUT);
pinMode(15,INPUT);
Wire1.setSDA(14);
Wire1.setSCL(15);

Wire1.begin(0x44);

Serial.begin(9600);
while (!Serial)
delay(10);

if (sht.init()) {
Serial.print("init(): success\n");
} else {
Serial.print("init(): failed\n");
}
sht.setAccuracy(SHTSensor::SHT_ACCURACY_MEDIUM);
}

void loop() {
if (sht.readSample()) {
actualHumidity = sht.getHumidity();
Serial.print(actualHumidity, 2);
Serial.print("\n");
Serial.print(" T: ");
actualTemperature = sht.getTemperature();
Serial.print(actualTemperature, 2);
Serial.print("\n");
Serial.print("Reading SHT40 Data...OK\n");
} else {
Serial.print("Error in readSample()\n"); // this is being displayed in serial monitor - so sht.readSample() doesnt read anything
}
delay(1000);
}
`

[winkj]

on a cursory check, I believe you didn't initialize the SHT library on Wire1. Could you change the call of sht.init() to sht.init(Wire1) and try again?

[TheLennyLeonard]

thanks for fast reply...still getting the same message: Error in readSample() as you can see in my code.

[winkj]

could you print the complete output? sht.init() should fail if the sensor is not detected ("init(): failed"), before readSample(). It should have either printed an error before (defaulting to Wire) or after the change to use Wire1, unless the Pi pico platform is working differently than other Arduinos.

As a further test, running I2CScanner helps: https://playground.arduino.cc/Main/I2cScanner/. This should detect a sensor responding on the SHT40's I2C address 0x44. This should help narrow down the root cause

[TheLennyLeonard]

yeah, I was getting init(): failed responses...so I tried the I2C scanner and even the scanner cant find it...
I am afraid that because it is a pico not arduino...it will never gonna work. Tried to change pins on pico, so I can use Wire instead of Wire1.

here is the code:
`#include <Wire.h>

const byte PICO_I2C_ADDRESS = 0x44;
const byte PICO_HUMIDITY_PRECISION = 0xFD; // high precission
const byte PICO_I2C_SDA = 12;
const byte PICO_I2C_SCL = 13;

void setup()
{
pinMode(14,INPUT);
pinMode(15,INPUT);
Wire.setSDA(PICO_I2C_SDA);
Wire.setSCL(PICO_I2C_SCL);
Wire.begin();

Serial.begin(9600);
while (!Serial); // Leonardo: wait for serial monitor
Serial.println("\nI2C Scanner");
}

void loop()
{
byte error, address;
int nDevices;

Serial.println("Scanning...");

nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();

if (error == 0)
{
  Serial.print("I2C device found at address 0x");
  if (address<16)
    Serial.print("0");
  Serial.print(address,HEX);
  Serial.println("  !");

  nDevices++;
}
else if (error==4)
{
  Serial.print("Unknown error at address 0x");
  if (address<16)
    Serial.print("0");
  Serial.println(address,HEX);
}    

}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");

delay(5000); // wait 5 seconds for next scan
}
`
getting No I2C devices found...