├── .gitignore
├── LICENSE
├── README.md
├── component.mk
├── dht11.c
├── examples
    └── simple_read.c
├── include
    └── dht11.h
└── library.json


/.gitignore:
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 1 | # Prerequisites
 2 | *.d
 3 | 
 4 | # Object files
 5 | *.o
 6 | *.ko
 7 | *.obj
 8 | *.elf
 9 | 
10 | # Linker output
11 | *.ilk
12 | *.map
13 | *.exp
14 | 
15 | # Precompiled Headers
16 | *.gch
17 | *.pch
18 | 
19 | # Libraries
20 | *.lib
21 | *.a
22 | *.la
23 | *.lo
24 | 
25 | # Shared objects (inc. Windows DLLs)
26 | *.dll
27 | *.so
28 | *.so.*
29 | *.dylib
30 | 
31 | # Executables
32 | *.exe
33 | *.out
34 | *.app
35 | *.i*86
36 | *.x86_64
37 | *.hex
38 | 
39 | # Debug files
40 | *.dSYM/
41 | *.su
42 | *.idb
43 | *.pdb
44 | 
45 | # Kernel Module Compile Results
46 | *.mod*
47 | *.cmd
48 | .tmp_versions/
49 | modules.order
50 | Module.symvers
51 | Mkfile.old
52 | dkms.conf
53 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
 1 | MIT License
 2 | 
 3 | Copyright (c) 2018 Michele Biondi
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy
 6 | of this software and associated documentation files (the "Software"), to deal
 7 | in the Software without restriction, including without limitation the rights
 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9 | copies of the Software, and to permit persons to whom the Software is
10 | furnished to do so, subject to the following conditions:
11 | 
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 | 
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 | SOFTWARE.
22 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | # ESP32-DHT11
 2 | Esp-idf driver for DHT11 temperature and humidity sensor
 3 | 
 4 | ## Install
 5 | Use Platformio to install this [link](https://platformio.org/lib/show/5817/ESP32-DHT11)<br/>
 6 | or <br/>
 7 | Clone this repo inside [esp]/esp-idf/components folder
 8 | 
 9 | ## How to use
10 | Import dht11.h inside your program, initialize the device with DHT11_init(gpio_num) and then call DHT11_read() whenever you need to read from the DHT11 sensor.<br/>
11 | DHT11_read() returns a struct with temperature and humidity and a status code of the operation for error checking.<br/>
12 | 
13 | Check the examples folder for more information.
14 | 
15 | <b>WARNING</b>: DHT11_read() is a blocking function.
16 | 


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/component.mk:
--------------------------------------------------------------------------------
1 | #
2 | # Main Makefile. This is basically the same as a component makefile.
3 | #


--------------------------------------------------------------------------------
/dht11.c:
--------------------------------------------------------------------------------
  1 | /*
  2 |  * MIT License
  3 |  * 
  4 |  * Copyright (c) 2018 Michele Biondi
  5 |  * 
  6 |  * Permission is hereby granted, free of charge, to any person obtaining a copy
  7 |  * of this software and associated documentation files (the "Software"), to deal
  8 |  * in the Software without restriction, including without limitation the rights
  9 |  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 10 |  * copies of the Software, and to permit persons to whom the Software is
 11 |  * furnished to do so, subject to the following conditions:
 12 |  * 
 13 |  * The above copyright notice and this permission notice shall be included in all
 14 |  * copies or substantial portions of the Software.
 15 |  * 
 16 |  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 17 |  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 18 |  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 19 |  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 20 |  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 21 |  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 22 |  * SOFTWARE.
 23 | */
 24 | 
 25 | #include "esp_timer.h"
 26 | #include "driver/gpio.h"
 27 | #include "rom/ets_sys.h"
 28 | #include "freertos/FreeRTOS.h"
 29 | #include "freertos/task.h"
 30 | 
 31 | #include "dht11.h"
 32 | 
 33 | static gpio_num_t dht_gpio;
 34 | static int64_t last_read_time = -2000000;
 35 | static struct dht11_reading last_read;
 36 | 
 37 | static int _waitOrTimeout(uint16_t microSeconds, int level) {
 38 |     int micros_ticks = 0;
 39 |     while(gpio_get_level(dht_gpio) == level) { 
 40 |         if(micros_ticks++ > microSeconds) 
 41 |             return DHT11_TIMEOUT_ERROR;
 42 |         ets_delay_us(1);
 43 |     }
 44 |     return micros_ticks;
 45 | }
 46 | 
 47 | static int _checkCRC(uint8_t data[]) {
 48 |     if(data[4] == (data[0] + data[1] + data[2] + data[3]))
 49 |         return DHT11_OK;
 50 |     else
 51 |         return DHT11_CRC_ERROR;
 52 | }
 53 | 
 54 | static void _sendStartSignal() {
 55 |     gpio_set_direction(dht_gpio, GPIO_MODE_OUTPUT);
 56 |     gpio_set_level(dht_gpio, 0);
 57 |     ets_delay_us(20 * 1000);
 58 |     gpio_set_level(dht_gpio, 1);
 59 |     ets_delay_us(40);
 60 |     gpio_set_direction(dht_gpio, GPIO_MODE_INPUT);
 61 | }
 62 | 
 63 | static int _checkResponse() {
 64 |     /* Wait for next step ~80us*/
 65 |     if(_waitOrTimeout(80, 0) == DHT11_TIMEOUT_ERROR)
 66 |         return DHT11_TIMEOUT_ERROR;
 67 | 
 68 |     /* Wait for next step ~80us*/
 69 |     if(_waitOrTimeout(80, 1) == DHT11_TIMEOUT_ERROR) 
 70 |         return DHT11_TIMEOUT_ERROR;
 71 | 
 72 |     return DHT11_OK;
 73 | }
 74 | 
 75 | static struct dht11_reading _timeoutError() {
 76 |     struct dht11_reading timeoutError = {DHT11_TIMEOUT_ERROR, -1, -1};
 77 |     return timeoutError;
 78 | }
 79 | 
 80 | static struct dht11_reading _crcError() {
 81 |     struct dht11_reading crcError = {DHT11_CRC_ERROR, -1, -1};
 82 |     return crcError;
 83 | }
 84 | 
 85 | void DHT11_init(gpio_num_t gpio_num) {
 86 |     /* Wait 1 seconds to make the device pass its initial unstable status */
 87 |     vTaskDelay(1000 / portTICK_PERIOD_MS);
 88 |     dht_gpio = gpio_num;
 89 | }
 90 | 
 91 | struct dht11_reading DHT11_read() {
 92 |     /* Tried to sense too son since last read (dht11 needs ~2 seconds to make a new read) */
 93 |     if(esp_timer_get_time() - 2000000 < last_read_time) {
 94 |         return last_read;
 95 |     }
 96 | 
 97 |     last_read_time = esp_timer_get_time();
 98 | 
 99 |     uint8_t data[5] = {0,0,0,0,0};
100 | 
101 |     _sendStartSignal();
102 | 
103 |     if(_checkResponse() == DHT11_TIMEOUT_ERROR)
104 |         return last_read = _timeoutError();
105 |     
106 |     /* Read response */
107 |     for(int i = 0; i < 40; i++) {
108 |         /* Initial data */
109 |         if(_waitOrTimeout(50, 0) == DHT11_TIMEOUT_ERROR)
110 |             return last_read = _timeoutError();
111 |                 
112 |         if(_waitOrTimeout(70, 1) > 28) {
113 |             /* Bit received was a 1 */
114 |             data[i/8] |= (1 << (7-(i%8)));
115 |         }
116 |     }
117 | 
118 |     if(_checkCRC(data) != DHT11_CRC_ERROR) {
119 |         last_read.status = DHT11_OK;
120 |         last_read.temperature = data[2];
121 |         last_read.humidity = data[0];
122 |         return last_read;
123 |     } else {
124 |         return last_read = _crcError();
125 |     }
126 | }
127 | 


--------------------------------------------------------------------------------
/examples/simple_read.c:
--------------------------------------------------------------------------------
 1 | /* Simple Read Example
 2 | 
 3 |    This example code is in the Public Domain (or CC0 licensed, at your option.)
 4 | 
 5 |    Unless required by applicable law or agreed to in writing, this
 6 |    software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
 7 |    CONDITIONS OF ANY KIND, either express or implied.
 8 | */
 9 | #include "freertos/FreeRTOS.h"
10 | #include "freertos/task.h"
11 | #include "driver/gpio.h"
12 | #include "sdkconfig.h"
13 | 
14 | #include "waiter.h"
15 | #include "dht11.h"
16 | 
17 | void app_main()
18 | {
19 |     DHT11_init(GPIO_NUM_4);
20 | 
21 |     while(1) {
22 |         printf("Temperature is %d \n", DHT11_read().temperature);
23 |         printf("Humidity is %d\n", DHT11_read().humidity);
24 |         printf("Status code is %d\n", DHT11_read().status);
25 |         waitSeconds(1);
26 |     }
27 | }
28 | 


--------------------------------------------------------------------------------
/include/dht11.h:
--------------------------------------------------------------------------------
 1 | /*
 2 |  * MIT License
 3 |  * 
 4 |  * Copyright (c) 2018 Michele Biondi
 5 |  * 
 6 |  * Permission is hereby granted, free of charge, to any person obtaining a copy
 7 |  * of this software and associated documentation files (the "Software"), to deal
 8 |  * in the Software without restriction, including without limitation the rights
 9 |  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 |  * copies of the Software, and to permit persons to whom the Software is
11 |  * furnished to do so, subject to the following conditions:
12 |  * 
13 |  * The above copyright notice and this permission notice shall be included in all
14 |  * copies or substantial portions of the Software.
15 |  * 
16 |  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 |  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 |  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 |  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 |  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 |  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 |  * SOFTWARE.
23 | */
24 | 
25 | #ifndef DHT11_H_
26 | #define DHT11_H_
27 | 
28 | #include "driver/gpio.h"
29 | 
30 | enum dht11_status {
31 |     DHT11_CRC_ERROR = -2,
32 |     DHT11_TIMEOUT_ERROR,
33 |     DHT11_OK
34 | };
35 | 
36 | struct dht11_reading {
37 |     int status;
38 |     int temperature;
39 |     int humidity;
40 | };
41 | 
42 | void DHT11_init(gpio_num_t);
43 | 
44 | struct dht11_reading DHT11_read();
45 | 
46 | #endif


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/library.json:
--------------------------------------------------------------------------------
 1 | {
 2 |     "name": "ESP32-DHT11",
 3 |     "keywords": "DHT11, esp32, esp-idf, espressif, temperature, humidity",
 4 |     "description": "Full featured driver to use DHT11 sensor on esp32 with esp-idf",
 5 |     "authors": {
 6 |         "name": "Michele Biondi",
 7 |         "email": "michelebiondi01@gmail.com",
 8 |         "maintainer": true
 9 |     },
10 |     "repository": {
11 |         "type": "git",
12 |         "url": "https://github.com/an4cr0n/esp32-DHT11.git"
13 |     },
14 |     "version": "1.0.1",
15 |     "frameworks": "espidf",
16 |     "platforms": "espressif32"
17 | }
18 | 


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