Measure the current temperature

We use Mongoose OS + esp8266 + DHT11 To do it .

• Mongoose OS： An Internet of things The firmware Development framework . Official documents

• esp8266：ESP8266 Is a A serial port WiFi modular .

• DHT11： A temperature sensor .

• The firmware ： It can be understood as the operating system of an electronic product , It is the software at the bottom of the hardware .

• A serial port ： Look at the picture directly

  

  

  You can send eight bits of data at one time , Mutual interference , If one bit of parallel port transmission error occurs, it is necessary to resend the eight bit data , One bit of serial port transmission error only needs to be sent again .

One 、Hello World

1. download mongoose OS The official tool of mos.exe, Double click or enter a command mos ui You can start it UI Interface . If it doesn't start , Open Command Prompt , Input cd c:\mos then mos --start-webview=false. Need to close when closing 1992 Service of port （ Otherwise, double clicking again will not open ui Interface ）.

   

2. With a data cable （ It must be a data line that can transmit data , Some cables can only be charged ） Connect esp8266, Install the corresponding driver according to your own requirements .

   • Lexin motherboard Silabs The driver

   • Lexin development board CH43x The driver

   • CC3200、CC3220 Of FTDI The driver

   Installation driver ：1. Right click this computer -> management -> Device manager -> Other equipment

   The yellow exclamation point is the driver we need to install , After installation, you can see which port the device is on in the port .

3. open mos, Select port and model , The port and model shall be selected according to the actual situation , I use it esp8266 2m All choices of memory esp8266 flash 2m.

4. stay ui There is a line of text box below which you can enter commands , Input mos clone https://github.com/mongoose-os-apps/demo-c app1 Clone a template . After cloning, we can see a in the corresponding directory app1 Folder , The contents of this catalog are src In the catalog main.c It's our code ,mos.yml It's a configuration file , Describe the entire application .

5. open main.c, find

   It is amended as follows ：

   

6. stay mos Of ui Input... In the interface mos build Compile code .

7. After a long wait, enter mos flash Brush the firmware into .

8. One sentence per second will be output after success hello world!

   

Two 、 Use DHT11 Thermometry

First put our dht11 Connect to esp8266 On ,vcc or + Connect 3v The pin of , GND or - even GND, DAT or out even IO Pin （IO Just remember , Like I take it IO2 Pin , It will be configured as IO2 Pin ）.

esp8266 Pin figure ：

After the connection is completed, we just need to hello world The program is slightly modified ：

1. Add dependency ：

   stay mos.yml Of libs Add below dht Driven dependency （ These drivers can be used in mongoose Find... On the official website ）, if necessary rpc Services can be added rpc rely on .

   libs:
     - location: https://github.com/mongoose-os-libs/boards
     - location: https://github.com/mongoose-os-libs/demo-bundle
     - location: https://github.com/mongoose-os-libs/rpc-service-config
     - location: https://github.com/mongoose-os-libs/rpc-service-fs
     - location: https://github.com/mongoose-os-libs/rpc-uart
     - location: https://github.com/mongoose-os-libs/wifi
     - location: https://github.com/mongoose-os-libs/dht
   

2. Configure pins , Modify the code ：

   stay mos.yml Add ：

   config_schema:
     - ["app.pin", "i", 2, {
         title: "GPIO pin a sensor is attached to"}]
     # Because just now I was io2 Pin , So this is 2
   

   main.c：

   #include "mgos.h"
   #include "mgos_dht.h"
   
   static void timer_cb(void *dht) {
         
     LOG(LL_INFO, ("Temperature: %lf", mgos_dht_get_temp(dht)));
   }
   
   
   enum mgos_app_init_result mgos_app_init(void) {
         
     struct mgos_dht *dht = mgos_dht_create(mgos_sys_config_get_app_pin(), DHT11);
     mgos_set_timer(1000, true, timer_cb, dht);
     return MGOS_APP_INIT_SUCCESS;
   }
   

   It seems complicated , There are actually only two important functions ：

   mgos_dht_create(mgos_sys_config_get_app_pin(), DHT11);

   mgos_dht_get_temp(dht)

   initialization dht And get the temperature .

3. compile & Firmware brush in

   stay mos Of ui Input... In the interface mos build After successful compilation, enter mos flash Brush in the firmware .

4. effect ：