Tip : Writting data from sensors to SDCard : M5Stack > UIflow (micropython code)

Serge

Hi, this is a script that works well for me.
Context : during an experiment, you want to save data collected from sensors.
You re doing many acquisitions so you need to save data in many files.
Hope it will help.

In this example, data (temperature and humidity) is generated by random numbers.

from m5stack import *
from m5ui import *
from uiflow import *
import os
import time
from random import randint

last_time = 0
Time_Interval = 5    #wait 5 seconds before the new data acquisition
abscisse = []        # the data is collected in 3 lists  
temperatures = []
humidities = []
label0 = M5TextBox(50, 140, "", lcd.FONT_DejaVu18,0xFFFFFF, rotate=0)

# don't know why it s works without the sd_mount() instruction
#sd_mount()

# this function for a brand new screen
def refresh_screen():
  setScreenColor(0x222222)
  lcd.font(lcd.FONT_DejaVu18)
  lcd.print("Welcome !", 10 , 20, 0xFFFFFF)
  lcd.print("Writing Data on SDCard", 10 , 40, 0xFFFFFF)
  lcd.print("Please Press Button B", 10 , 60, 0xFFFFFF)
  lcd.print("         to save file", 10 , 80, 0xFFFFFF)  
  lcd.print("Current File length", 10 , 100, 0xFFFFFF)  
  wait(0)

# test if a file is already existing  
def file_exists(fname):
  try:
    with open(fname):
      pass
    return True
  except OSError:
     return False

refresh_screen()
t0 = time.ticks_ms()

while True:
  if  (time.ticks_ms()-last_time) >= Time_Interval*1000:
    last_time = time.ticks_ms()
    new_time = (time.ticks_ms()-t0) // 1000
    # when it s time, you can collect a new data from a sensor
    # some kind of env.get_temperature, works here with numbers
    temp = randint(200,300) / 10  # random number for temperature in °C
    humi = randint(40,60)         # random number for humidity in %
    abscisse.append(new_time)     # writing new value in each list
    temperatures.append(temp)
    humidities.append(humi)
    label0.setText(str(len(abscisse)))
    wait(0.1)

  if btnB.isPressed():
      file_path = "/sd/MeasuresTH0.txt"
      while file_exists(file_path):   # create a new file name if several acquisitions
        file_path = file_path.replace("/sd/MeasuresTH"," ")
        file_path = file_path.replace(".txt"," ")
        file_path = file_path.strip()
        file_path = int(file_path) + 1
        file_path = "/sd/MeasuresTH"+str(file_path)+".txt"
      f1 = open(file_path, 'w+', encoding="utf-8") # the file operations for writing     on SDcard all the data in the same file
      f1.write("{} \n".format(abscisse))
      f1.write("{} \n".format(temperatures))
      f1.write("{} \n".format(humidities))
      f1.close()
      label0.setText("Saved in \n" + file_path)   
      wait(2)
      # reset all stuff and do it again
      t0 = time.ticks_ms()
      last_time = 0
      abscisse = []
      temperatures = []
      humidities = []
      setScreenColor(0x222222)
      refresh_screen()