How to Make a Temperature Gun With Esp32 | Details

What a hot day it is! Too hot to drive and ride and I am thinking of making a temperature measurement sensor. MLX90614 (a noncontact IR temperature sensor) on hand, let’s do it!

Hardware &software in need

Hardware in need

Hardware List
FireBeetle ESP32 IOT Microcontroller×1
Gravity: Non-contact IR Temperature Sensor for Arduino ×1
Gravity I2C OLED-2864 Display ×1
3.7V 400mAh Lithium battery ×1
Red laser transmitter (diameter: 6mm) ×1
C&K slide switch ×1
3D printing crust set (2 parts) ×1

Tools
Thermo-control Anti-Static Soldering Station AT936b
Overlord Pro 3D printer
401 glue
Hot melt gun

Software list
MLX90614.py (library file of MLX90614 noncontact IR temperature sensor)
SSD1306.py (library file of Gravity IIC OLED-2864 display)
piclib.py (library file of show pictures and 16*24 script used in the project)
InfraRedThermometer.py (source files of project codes)
uPyCraft MicroPython IDE
PCtoLCD2002 LCD impression taking software
3D printing slice software: Cura
3D printing file: 3D print - left part.stl (available for direct printing of Overload Pro 3D printer)
3D printing file: 3D print - right part.stl

Operating process
1. Solder components as below:

Connection diagram

2. Transform show pictures and 16*24 script in use to hexadecimal code with PCtoLCD2002 LCD impression taking software

Setting and take impression as below:

3. Programing with uPyCraft MicroPython IDE and burn codes to FireBeetle ESP32.

Check after codes burnt.

import MLX90614
from machine import Pin,I2C
import time
import ssd1306
from piclib import *
# This code will show you how to make a Infra Red Thermometer using the MLX90614 sensor.
 
 
i2c = I2C(scl=Pin(22), sda=Pin(21), freq=100000)
ir=MLX90614.MLX90614(i2c)
lcd=ssd1306.SSD1306_I2C(128,64,i2c)
 
#Display a picture 72*64 
def DisplayPicture(x,y,picture):
  for line in range(0,64):
    for bytes in range(0,9):
      for bits in range(0,8):
        if picture[9*line+bytes]&0x80>>bits:
          lcd.pixel(x+bytes*8+bits,y+line,1)
        else:
          lcd.pixel(x+bytes*8+bits,y+line,0)
  return
 
#Display a character 16*24 
def DisplayCharacter16X24(x,y,character):
  for line in range(0,24):
    for bytes in range(0,2):
      for bits in range(0,8):
        if character[line*2+bytes]&0x80>>bits:
          lcd.pixel(x+bytes*8+bits,y+line,1)
        else:
          lcd.pixel(x+bytes*8+bits,y+line,0)
  return
 
#---------------------run here------------------------------------  
#display logo
DisplayPicture(28,0,picture) 
lcd.show()
time.sleep(1)
lcd.fill(0)
 
#display O:123.4C
#        A:123.4C 
DisplayCharacter16X24(0,0,charArray[10]) #O
DisplayCharacter16X24(16*1,0,charArray[12]) #:
DisplayCharacter16X24(16*7,0,charArray[13]) #C
 
DisplayCharacter16X24(0,24,charArray[11]) #A
DisplayCharacter16X24(16*1,24,charArray[12]) #:
DisplayCharacter16X24(16*7,24,charArray[13]) #C
lcd.show()
 
 
while True:
  time.sleep(0.2)
  Object = ir.getObjCelsius() #  *C
  Ambient = ir.getEnvCelsius() # *C
  #Object = ir.getObjFahrenheit() # *F
  #Ambient = ir.getEnvFahrenheit() # *F
  #print("Object  %s *C"% Object)
  #print("Ambient %s *C"% Ambient)
  #print()
  ObjectInt = int(Object*10)
  AmbientInt = int(Ambient*10)
  if ObjectInt < 0:
    ObjectInt = abs(ObjectInt)
    DisplayCharacter16X24(16*2,0,charArray[15])# -
    temp1 = (ObjectInt%1000)//100
    if(temp1 == 0):
      DisplayCharacter16X24(16*3,0,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*3,0,charArray[temp1])
    DisplayCharacter16X24(16*4,0,charArray[(ObjectInt%100)//10])
    DisplayCharacter16X24(16*5,0,charArray[14]) # .
    DisplayCharacter16X24(16*6,0,charArray[ObjectInt%10]) 
    
  else:
    temp1 = ObjectInt//1000
    temp2 = (ObjectInt%1000)//100
    if temp1 == 0:
      DisplayCharacter16X24(16*2,0,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*2,0,charArray[temp1])
    if temp1 == 0 and temp2 == 0:
      DisplayCharacter16X24(16*3,0,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*3,0,charArray[temp2])
    DisplayCharacter16X24(16*4,0,charArray[(ObjectInt%100)//10])
    DisplayCharacter16X24(16*5,0,charArray[14]) # .
    DisplayCharacter16X24(16*6,0,charArray[ObjectInt%10]) 
  
  if AmbientInt < 0:
    ObjectInt = abs(AmbientInt)
    DisplayCharacter16X24(16*2,24,charArray[15])# -
    temp1 = (AmbientInt%1000)//100
    if temp1 == 0:
      DisplayCharacter16X24(16*3,24,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*3,24,charArray[temp1])
    DisplayCharacter16X24(16*4,24,charArray[(AmbientInt%100)//10])
    DisplayCharacter16X24(16*5,24,charArray[14]) # .
    DisplayCharacter16X24(16*6,24,charArray[AmbientInt%10]) 
    
  else:
    temp1 = AmbientInt//1000
    temp2 = (AmbientInt%1000)//100
    if temp1 == 0:
      DisplayCharacter16X24(16*2,24,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*2,24,charArray[temp1])
    if temp1 == 0 and temp2 == 0:
      DisplayCharacter16X24(16*3,24,charArray[16]) # space
    else:
      DisplayCharacter16X24(16*3,24,charArray[temp2])
    DisplayCharacter16X24(16*4,24,charArray[(AmbientInt%100)//10])
    DisplayCharacter16X24(16*5,24,charArray[14]) # .
    DisplayCharacter16X24(16*6,24,charArray[AmbientInt%10])  
  lcd.show()

4. Designing crusts according to dimension of components.

5. Use Cura (a 3D printing slice software) to make 3D printing files.

6. Print crusts with Overload Pro 3D printer.

7. Allocate components to inner part of printed crusts with hot melt and glue.

8. Temperature measurement

Measure temperature of palm

Measure temperature of mobike saddle

Measure temperature of freezer

Now, we have accomplished the procedure of practical noncontact temperature measurement gun. You can modify this program according to effective demands. For example, you can upload results to Internet of Things or cellphones with Wi-Fi and BLE Bluetooth in FireBeetle ESP32. I am always cannot recollect whether I have turned off gas cooker when I got out, so a noncontact temperature measurement gun that can upload data to IoT or phone is very helps me a lot.

Project Details