Graph with temperature sensor DHT11

[stanislas.guiot.sams]

Hi,

I want to put a graphic about the temperature measured with a DT11.
I’m using a arduino connected by wifi using a ESP01 card. ( I know that’s not a very good hardware choice but it’s economicaly very good. )

It’s just to inform that there is a bug with the graphic with temperature sensor because the convertion in celsius doesn’t work.

My sensor send a value in fareinheit, if I select to show a value with the unit in celsius the value shown on the display is well converted in celsius. But if I select a graphic, even if I select the unit in celsius, it’ a graphic with fareinheit units.

best regards.

[rsiegel]

Hi @stanislas.guiot.sams,

No worries about the hardware choice here, for this sort of issue that shouldn’t matter. Thanks for the bug report, I do apologize for the trouble.

Would you mind sharing the sketch code you’re using to publish the temperature value to Cayenne so I can try to reproduce this error on our side? You can blank out your Cayenne Token or any other personal information.

[stanislas.guiot.sams]

this is the code I’m using on the Wemos D1 card equiped with a DHT11:

#include <DHT.h>
#include <CayenneMQTTESP8266.h>
#define DHTPIN 2
#define DHTTYPE DHT11
#define CAYENNE_PRINT Serial

// wifi informations
char ssid = “xxxxxxxxxx”;
char wifiPassword = “xxxxxxx”;

// Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
char username = “xxxxxxxxxx”;
char password = “xxxxxxxx”;
char clientID = “xxxxxx”;

DHT dht(D8, DHTTYPE);

void setup() {
Serial.begin(9600);
Cayenne.begin(username, password, clientID, ssid, wifiPassword);

pinMode(2,OUTPUT);
digitalWrite(2,HIGH);
}

void loop() {
Cayenne.loop();
delay(2000);
float temp = dht.readTemperature(true);
float hum = dht.readHumidity();
Cayenne.virtualWrite(1,temp,TYPE_TEMPERATURE,UNIT_FAHRENHEIT);
Cayenne.virtualWrite(2,hum,TYPE_RELATIVE_HUMIDITY,UNIT_PERCENT);
}

CAYENNE_IN(0)
{
digitalWrite(2,!getValue.asInt());
}

CAYENNE_IN_DEFAULT()
{
CAYENNE_LOG(“CAYENNE_IN_DEFAULT(%u) - %s, %s”, request.channel, getValue.getId(), getValue.asString());
getValue.setError(“Error message”);
}

this is the configuration :

this is the overview panel:

As you can see the temperature is in fareihneit even if the configuration is in celcius.
trust me the temperature in my workshop is not around 62°C

If I select fareihneit it steel the same graph.

if I select only a value display, the parameter celsius or fareihneit work very well.

In celsius :

In fareihneit :

best regards.

[rsiegel]

I trust you, that would be pretty hot!

I can reproduce on my side now, thank you for the detailed information. Until we get this bug squashed, you might want to consider doing the conversion from F to C in your sketch code so you aren’t relying on the one internal to Cayenne.

[stanislas.guiot.sams]

I found an other bug

I steel use the DH11 sensor .
On my dashboard I select to show the temperature in celsius as a value.
it’s ok but if I open this dash board in the cayenne application on my android phone,
the conversion isn’t done. the value steel in Fahreinheit.

there is no parameter to select celsius or fahreinheit.

it’s righten celsius but the value is in fahreihneit.

best regards.

[rsiegel]

I see this issue as well, thank you for pointing it out. The unit label selected on web syncs to the mobile app, but the units pass across unconverted. Definitely something we’ll need to sort out. Until then, it looks like you’ll have an easier time if you convert to the desired units in your client code and just publish the value that way so it doesn’t need any conversion on the Cayenne side.