ENV sensor calibration

charlestondance

Well that is not much use then!

Is the problem the supplier or the device or the code?

If the offset is the same within a certain range surely you could just subtract a constant? the issue is i have no way to measure humidity and pressure independently.

ajb2k3

@charlestondance I suppose you can try using the maths blocks but I have to ask (don't take this personally) are you sure your how thermostat is calibrated?

In UIFlow, the temperature is returned as a value and so you can add that to a maths block as a variable number.
Below is a quick code test (sorry had to retrieve the kit from the office/studio. alt text

Wolli01

@ajb2k3 Yes, the humidity results are really bad.
How can I e.g. connect my own sensor SHT series?
On my Pycom Wipy I have something like this running successfully.
I like to set the code to change it for M5Stack.

ajb2k3

Connecting the sensor depends on many things like operating characteristics.
Can you post a link to the sensor you are looking at?
Sometime its just a case of plug and play, sometimes its a case of hacing some code.

Wolli01

@ajb2k3
https://www.sensirion.com/en/environmental-sensors/humidity-sensors/digital-humidity-sensors-for-various-applications/

Of these I have the SHT 20/21 and the SHT 30/31 on my
Pycom Wipy/Lopy are doing well.

lukasmaximus

@Wolli01 The sensor you sent us a link to, is it on a breakout board with pinouts? and is it possible to communicate with it via i2c?

Wolli01

@lukasmaximus Yeah, no problems.
Enclosed the code that runs in Wipy over Python.

SHT31.PY
from machine import I2C
import time

R_HIGH = const(1)
R_MEDIUM = const(2)
R_LOW = const(3)

class SHT31(object):
"""
Diese Klasse implementiert eine Schnittstelle zur SHT31 Temperatur und Luftfeuchtigkeit.
Sensor von Sensirion.
"""
# Diese statische Karte hilft, den Heap und die Programmlogik sauber zu halten.
_map_cs_r = {
True: {
R_HIGH : b'\x2c\x06',
R_MEDIUM : b'\x2c\x0d',
R_LOW: b'\x2c\x10'
},
False: {
R_HIGH : b'\x24\x00',
R_MEDIUM : b'\x24\x0b',
R_LOW: b'\x24\x16'
}
}

def __init__(self, i2c, addr=0x44):
    """
    Initialisiert ein Sensorobjekt auf dem angegebenen I2C-Bus, auf das von der
    angegebene Adresse.
    """
    if i2c == None or i2c.__class__ != I2C:
        raise ValueError('I2C-Objekt als Argument benÃ¶tigt!')
    self._i2c = i2c
    self._addr = addr

def _send(self, buf):
    """
    Sendet das angegebene Pufferobjekt Ã¼ber I2C an den Sensor.
    """
    self._i2c.writeto(self._addr, buf)

def _recv(self, count):
    """
    Lesen von Bytes vom Sensor Ã¼ber I2C. Die Anzahl der Bytes kann angegeben werden.
    als Argument.
    Liefert ein Bytearray fÃ¼r das Ergebnis.
    """
    return self._i2c.readfrom(self._addr, count)

def _raw_temp_humi(self, r=R_HIGH, cs=True):
    """
    Lesen Sie die Rohtemperatur und Luftfeuchtigkeit vom Sensor ab und Ã¼berspringen Sie CRC. ÃœberprÃ¼fung.
    Liefert ein Tupel fÃ¼r beide Werte in dieser Reihenfolge.
    """
    if r not in (R_HIGH, R_MEDIUM, R_LOW):
        raise ValueError('Falscher Wiederholbarkeitswert angegeben!')
    self._send(self._map_cs_r[cs][r])
    time.sleep_ms(50)
    raw = self._recv(6)
    return (raw[0] << 8) + raw[1], (raw[3] << 8) + raw[4]

def get_temp_humi(self, resolution=R_HIGH, clock_stretch=True, celsius=True):
    """
    Lesen Sie die Temperatur in Grad Celsius oder Fahrenheit und relativ dazu ab.
    Feuchtigkeit. AuflÃ¶sung und TaktverlÃ¤ngerung kÃ¶nnen festgelegt werden.
    Liefert ein Tupel fÃ¼r beide Werte in dieser Reihenfolge.
    """
    t, h = self._raw_temp_humi(resolution, clock_stretch)
    if celsius:
        temp = -45 + (175 * (t / 65535.0))
    else:
        temp = -49 + (315 * (t / 65535.0))
    return temp, 100 * (h / 65535.0)

Main.PY
#Sensor SHT31-----------------------------------------------------------
if (Sensorwahl) == 'sht31':

i2c = I2C(0, I2C.MASTER, baudrate=100000)
sensor = sht31.SHT31(i2c, addr=0x44)
temp_humi = sensor.get_temp_humi()
time.sleep(0.6)

pycom.rgbled(0xff007f) # magenta
pycom.heartbeat(False) #Lampe ausschalten um Energie zu sparen

Temp1 = round(temp_humi[0],2)
Feuchte1 = round(temp_humi[1],2)
time.sleep(1)

print('----------------------------------------------------------------------')
print("Ohne Runden = Temperature: {} Â°C | Humidity: {} %".format(temp_humi[0], temp_humi[1]))
print('----------------------------------------------------------------------')

#Ãœbergabe der Sensorwerte---------------------------------------
Temp1 = (Temp1 + 0) #Ãœbergabe und Differenzeingabe
Feuchte1 = (Feuchte1 + 0) #Ãœbergabe und Differenzeingabe
#Ãœbergabe der Sensorwerte---------------------------------------

#Sensor SHT31-----------------------------------------------------------

lukasmaximus

The I2c implementation in UIflow firmware is a little weird, I think if you were to flash the standard micropython firmware and put the necessary libraries on there this would work fine.

Wolli01

@lukasmaximus Yes, I thought about that, but how do I get the display to work? I can't cope with that.

Wolli01

@lukasmaximus
Where can I find instructions how to integrate the M5Stack libraries into the MicroPython standard software on a M5Stack Core Grey/Black.

lukasmaximus

You need to use a command line program called ampy to move the libraries across. This guy wrote a guide in which he used the standard micropython firmware and added his own libraries https://www.hackster.io/andreas-motzek/execute-logo-on-m5stack-esp32-basic-with-micropython-3713fd