Honeywell H1H6131 Stops Updating [SOLVED]

[davegutz]

Using a Photon and Wire built-in package I am reading a Honeywell Temp/Humidistat over I2C. At the same time I am using I2C to write to an Adafruit LED mini matrix. After the first update following a power cycle the Honeywell device appears to freeze both temp and humidity.

There are two possibilities I have found by browsing:

1. The following suggests that the Honeywell H1H6131 is crappy and stops working by getting stuck like I see. This would be fixed by replacing the device (fairly involved have to disassemble completed project) with a different brand.

Wrong reading value for DH22 & get stuck after running for a while

I don’t know what are are working on I just wanted to provide a “share” to the community, incase you are looking for a sensor that won’t give you headaches down the road. imho the DHT22 good sensor for tinkering, and that’s about it. I evaluated a bunch of sensors early this year and all the DHT22 sensors got hung up eventually (regardless of the different libraries of code). I got some to just all together break, granted I was pretty tough on them in our temp and RH chamber (-20 - 70C ~30-95…

2 The following suggests that there is a Wire library issue I can workaround.

I2C on Spark core (noob question)

Let me add one last little bit of info: I had trouble with the HIH3160 in the past on RFduino’s I2C library too. The reason was that HIH3160 is triggered to initiate measurement by an empty transmission, but the I2C library was simply skipping further logic if the output buffer was empty at the time endTransmission() is called. I fixed it there by sending one random byte, which got around the issue. I didn’t originally suspect I2C library issues because someone else had posted an HIH61xx libr…

I have asked for a code fragment to try this and haven't received a reply yet. This would be quite easy but would leave me uneasy about the basic reliability.

I post here now in hopes somebody has some guidance for me, or just follow me along through the struggle.

Thanks for looking.

FYI the code (not showing the Adafruit stuff)

#define TEMP_SENSOR 0x27                    // Temp sensor bus address
#define readDelay       5000                // Sensor read wait, ms
#define TEMPCAL -8                          // Calibrate temp sense, F
bool                read;               // Read, T/F
double              temp            = 0.0;  // Sensed temp, F
int                 tempInt         = 0;    // Sensed integer temperature, F
...
void loop()
{
    unsigned long       now = millis();     // Keep track of time
...
    static unsigned int lastRead = 0;    // Last read time, ms
    read = (now-lastRead) >= readDelay;
    if ( read ) lastRead = now;
...
// Read sensors
    if ( read )
    {
        delay(40);
        Wire.requestFrom(TEMP_SENSOR, 4, true); // request 4 bytes information
        uint8_t b       = Wire.read();
        uint8_t bend    = Wire.endTransmission();
        I2C_Status      = bend;
        //
        int rawHum      = (b << 8) & 0x3f00;
        rawHum          |=Wire.read();
        hum             = roundf(rawHum / 163.83);
        //
        int rawTemp     = (Wire.read() << 6) & 0x3fc0;
        rawTemp         |=Wire.read() >> 2;
        temp            = (float(rawTemp)*165.0/16383.0 - 40.0)*1.8 + 32.0 + TEMPCAL; // convert to fahrenheit and calibrate
        tempInt         = roundf(temp);
    }
...
}

[davegutz]

Fixed it. Somehow during troubleshooting original build I rearranged the code sequence to delete “Wire.beginTransmission” statement. Below is a fragment that actually works.

 if ( read )
    {
        Wire.beginTransmission(TEMP_SENSOR);
        Wire.endTransmission();
        delay(40);
        Wire.requestFrom(TEMP_SENSOR, 4);
        Wire.write(byte(0));
        uint8_t b   = Wire.read();
        I2C_Status  = b >> 6;
        //
        int rawHum  = (b << 8) & 0x3f00;
        rawHum      |=Wire.read();
        hum         = roundf(rawHum / 163.83);
        //
        int rawTemp = (Wire.read() << 6) & 0x3fc0;
        rawTemp     |=Wire.read() >> 2;
        temp        = (float(rawTemp)*165.0/16383.0 - 40.0)*1.8 + 32.0 + TEMPCAL; // convert to fahrenheit and calibrate
        tempInt     = roundf(temp);
    }