Features:

• Temperature reporting from the Sender with high temperature alarm beeps and visuals on the Receiver
• Battery voltage reporting on the Sender (voltage value and icon) with low battery alert on the Receiver
• Visual indicator on the Sender when data is being sent: The LED is on when sending data. Toggle button B on the M5StickC to turn the LED indicator on/off. When off, the temperature is displayed in red text to still give a visual indicator when the device is sending data.
• Audible indicator on the Receiver when the data is received: Volume +/- and Mute controls are available. Single beep tells the user the temperature is below the threshold (default is 160 degrees F). Triple beep tells the user the temperature is above the threshold.
• Visual indicator on the Receiver when the temperature is above the threshold: The temperature text is displayed red when the temperature is too high.
• Non-blocking code with the use of timers and callbacks instead of loops and waits

Sender uiFlow (file):

Receiver uiFlow (file):

Sender Python code:

from m5stack import *
from m5ui import *
from uiflow import *
import espnow
import wifiCfg
import unit

setScreenColor(0x000000)
env0 = unit.get(unit.ENV, unit.PORTA)



wifiCfg.wlan_ap.active(True)
espnow.init()
title0 = M5Title(title="Sender", x=3 , fgcolor=0xFFFFFF, bgcolor=0x0000FF)
label0 = M5TextBox(5, 40, "--", lcd.FONT_DejaVu24,0xFFFFFF, rotate=0)
rectangle4 = M5Rect(1, 117, 79, 25, 0x9d9d9d, 0x9d9d9d)
label1 = M5TextBox(5, 83, "Battery (V):", lcd.FONT_DefaultSmall,0xFFFFFF, rotate=0)
rectangle0 = M5Rect(3, 120, 15, 20, 0x33ff33, 0x33ff33)
rectangle1 = M5Rect(23, 120, 15, 20, 0x33ff33, 0x33ff33)
rectangle2 = M5Rect(43, 120, 15, 20, 0x33ff33, 0x33ff33)
rectangle3 = M5Rect(63, 120, 15, 20, 0x33ff33, 0x33ff33)
label2 = M5TextBox(5, 100, "--", lcd.FONT_DefaultSmall,0xFFFFFF, rotate=0)
label3 = M5TextBox(38, 40, "O", lcd.FONT_DefaultSmall,0xFFFFFF, rotate=0)
label4 = M5TextBox(47, 40, "F", lcd.FONT_DejaVu24,0xFFFFFF, rotate=0)

import math

senderFlag = None
temperature = None
batteryVoltage = None
ledStatus = None
highTempAlarm = None
lowBatteryAlarm = None
dataPayload = None

def batteryIcon():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  if batteryVoltage >= 4.1:
    rectangle0.hide()
    rectangle0.setBgColor(0x33ff33)
    rectangle0.setBorderColor(0x33ff33)
    rectangle0.show()
    rectangle1.show()
    rectangle2.show()
    rectangle3.show()
  elif batteryVoltage < 4.1 and batteryVoltage >= 3.9:
    rectangle0.hide()
    rectangle0.setBgColor(0x33ff33)
    rectangle0.setBorderColor(0x33ff33)
    rectangle0.show()
    rectangle1.show()
    rectangle2.show()
    rectangle3.hide()
  elif batteryVoltage < 3.9 and batteryVoltage >= 3.7:
    rectangle0.hide()
    rectangle0.setBgColor(0x33ff33)
    rectangle0.setBorderColor(0x33ff33)
    rectangle0.show()
    rectangle1.show()
    rectangle2.hide()
    rectangle3.hide()
  elif batteryVoltage < 3.7 and batteryVoltage >= 3.5:
    rectangle0.hide()
    rectangle0.setBgColor(0x33ff33)
    rectangle0.setBorderColor(0x33ff33)
    rectangle0.show()
    rectangle1.hide()
    rectangle2.hide()
    rectangle3.hide()
  elif batteryVoltage < 3.5 and batteryVoltage >= 3.3:
    rectangle0.hide()
    rectangle0.setBgColor(0x33ff33)
    rectangle0.setBorderColor(0x33ff33)
    rectangle0.show()
    rectangle1.hide()
    rectangle2.hide()
    rectangle3.hide()
  else:
    rectangle0.hide()
    rectangle0.setBgColor(0xff0000)
    rectangle0.setBorderColor(0xff0000)
    rectangle0.show()
    rectangle1.hide()
    rectangle2.hide()
    rectangle3.hide()

def highTempFunction():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  if temperature > 160:
    highTempAlarm = 1
    label0.setColor(0xff0000)
  else:
    highTempAlarm = 0
    label0.setColor(0xffffff)

def lowBatteryFunction():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  if batteryVoltage < 3.3:
    lowBatteryAlarm = 1
    label2.setColor(0xff0000)
  else:
    lowBatteryAlarm = 0
    label2.setColor(0xffffff)



def send_cb(flag):
  global senderFlag,temperature,batteryVoltage,ledStatus,highTempAlarm,lowBatteryAlarm,dataPayload
  senderFlag = flag
  if ledStatus == 1:
    M5Led.on()
    timerSch.run('ledOffTimer', 872, 0x01)
  else:
    label0.setColor(0xff0000)
    timerSch.run('ledOffTimer', 872, 0x01)

  pass
espnow.send_cb(send_cb)


def buttonB_wasPressed():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  if ledStatus == 1:
    ledStatus = 0
  else:
    ledStatus = 1
  pass
btnB.wasPressed(buttonB_wasPressed)

@timerSch.event('ledOffTimer')
def tledOffTimer():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  M5Led.off()
  label0.setColor(0xffffff)
  pass

@timerSch.event('sendData')
def tsendData():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  temperature = round((env0.temperature) * 1.8 + 32)
  label0.setText(str(temperature))
  highTempFunction()
  dataPayload = [temperature, highTempAlarm, lowBatteryAlarm]
  espnow.send(id=1, data=str(dataPayload))
  pass

@timerSch.event('checkBatteryTimer')
def tcheckBatteryTimer():
  global senderFlag, temperature, batteryVoltage, ledStatus, highTempAlarm, lowBatteryAlarm, dataPayload
  batteryVoltage = axp.getBatVoltage()
  label2.setText(str(batteryVoltage))
  batteryIcon()
  lowBatteryFunction()
  pass


batteryVoltage = axp.getBatVoltage()
label2.setText(str(batteryVoltage))
batteryIcon()
espnow.add_peer('30:ae:a4:49:cd:9d', id=1)
ledStatus = 1
timerSch.run('checkBatteryTimer', 15000, 0x00)
timerSch.run('sendData', 9999, 0x00)

Receiver Python code:

from m5stack import *
from m5ui import *
from uiflow import *
import espnow
import wifiCfg

setScreenColor(0x000000)



wifiCfg.wlan_ap.active(True)
espnow.init()
title0 = M5Title(title="Receiver", x=3 , fgcolor=0xFFFFFF, bgcolor=0x0000ff)
label0 = M5TextBox(110, 85, "---", lcd.FONT_DejaVu56,0xFFFFFF, rotate=0)
label6 = M5TextBox(85, 150, "HIGH TEMPERATURE!", lcd.FONT_Default,0xff0000, rotate=0)
label7 = M5TextBox(90, 30, "Low battery on sender!", lcd.FONT_Default,0xff0000, rotate=0)
rectangle0 = M5Rect(40, 194, 233, 18, 0x7e7c7c, 0x7e7c7c)
label1 = M5TextBox(183, 85, "O", lcd.FONT_Default,0xFFFFFF, rotate=0)
label10 = M5TextBox(7, 196, "Vol", lcd.FONT_Default,0xffffff, rotate=0)
label2 = M5TextBox(194, 85, "F", lcd.FONT_DejaVu56,0xFFFFFF, rotate=0)
rectangle1 = M5Rect(45, 198, 220, 10, 0xFFFFFF, 0xFFFFFF)
label3 = M5TextBox(55, 220, "Vol-", lcd.FONT_Default,0xFFFFFF, rotate=0)
label4 = M5TextBox(235, 220, "Vol+", lcd.FONT_Default,0xFFFFFF, rotate=0)
label5 = M5TextBox(145, 220, "Mute", lcd.FONT_Default,0xFFFFFF, rotate=0)

senderMacAddr = None
messagePayload = None
list2 = None
volume = None
temperature = None
highTemperatureAlarm = None
rectWidth = None
lowBatteryAlarm = None

def displayVolume():
  global senderMacAddr, messagePayload, list2, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if rectWidth > 220:
    rectangle1.setSize(width=220)
  elif rectWidth < 0:
    rectangle1.setSize(width=0)
  else:
    rectangle1.setSize(width=rectWidth)

def displayTemperature():
  global senderMacAddr, messagePayload, list2, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if len(temperature) == 3:
    label0.setPosition(x=75)
    label0.setText(str(temperature))
  else:
    label0.setPosition(x=110)
    label0.setText(str(temperature))

def highTemperatureCheck():
  global senderMacAddr, messagePayload, list2, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if highTemperatureAlarm == '1':
    label0.setColor(0xff0000)
    label6.show()
    speaker.tone(1200, 100)
    speaker.tone(1300, 200)
    speaker.tone(1200, 100)
  else:
    label0.setColor(0xffffff)
    label6.hide()
    speaker.tone(1000, 100)

def lowBatteryCheck():
  global senderMacAddr, messagePayload, list2, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if lowBatteryAlarm == '1':
    label7.show()
  else:
    label7.hide()



def recv_cb(_):
  global senderMacAddr,messagePayload,list,volume,temperature,highTemperatureAlarm,rectWidth,lowBatteryAlarm
  senderMacAddr, _, messagePayload = espnow.recv_data(encoder='str')
  list2 = messagePayload.split(',')
  temperature = list2[0].replace('[', '').strip()
  highTemperatureAlarm = list2[1].strip()
  lowBatteryAlarm = list2[2].replace(']', '').strip()
  displayTemperature()
  highTemperatureCheck()
  lowBatteryCheck()

  pass
espnow.recv_cb(recv_cb)


def buttonA_wasPressed():
  global senderMacAddr, messagePayload, list, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if volume < 0:
    label5.setColor(0xff0000)
    volume = 0
    speaker.setVolume(volume)
  else:
    label5.setColor(0xffffff)
    volume = volume - 0.1
    speaker.setVolume(volume)
    rectWidth = rectWidth - 22
  displayVolume()
  pass
btnA.wasPressed(buttonA_wasPressed)

def buttonB_wasPressed():
  global senderMacAddr, messagePayload, list, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  if volume > 0:
    label5.setColor(0xff0000)
    volume = 0
    speaker.setVolume(volume)
    rectangle1.setSize(width=0)
  else:
    label5.setColor(0xffffff)
    volume = 0.5
    speaker.setVolume(volume)
    rectangle1.setSize(width=110)
  pass
btnB.wasPressed(buttonB_wasPressed)

def buttonC_wasPressed():
  global senderMacAddr, messagePayload, list, volume, temperature, highTemperatureAlarm, rectWidth, lowBatteryAlarm
  label5.setColor(0xffffff)
  if volume > 1:
    volume = 1
    speaker.setVolume(volume)
  else:
    volume = volume + 0.1
    speaker.setVolume(volume)
    rectWidth = rectWidth + 22
  displayVolume()
  pass
btnC.wasPressed(buttonC_wasPressed)


volume = 0.5
speaker.setVolume(volume)
label6.hide()
label7.hide()
rectWidth = 110
rectangle1.setSize(width=rectWidth)
while True:
  wait_ms(2)