DHT Family of Humidity and Temperature Sensors

Device driver for the DHT Family of humidity and temperature sensors.

This driver provides [S]ensor [A]ctuator [U]ber [L]ayer capabilities.

enum @117

DHT_OK =  0

all good

DHT_NOCSUM = -1

checksum error

DHT_NODEV = -2

device type not defined

enum dht_type_t

DHT11

DHT11 device identifier.

DHT22

DHT22 device identifier.

DHT21 = DHT22

DHT21 device identifier.

dht_t dht_params_t

Configuration parameters for DHT devices.

int dht_init(dht_t * dev, const dht.h::dht_params_t * params)

Initialize a new DHT device.

Parameters

dev:device descriptor of a DHT device params:configuration parameters

Return values

• 0 on success
• -1 on error

int dht_read(const dht_t * dev, int16_t * temp, int16_t * hum)

get a new temperature and humidity value from the device

Note

if reading fails or checksum is invalid, no new values will be written into the result values

Parameters

dev:device descriptor of a DHT device temp:temperature value [in °C * 10^-1] hum:relative humidity value [in percent * 10^-1]

Return values

• 0 on success
• -1 on checksum error
• -2 on parsing error

struct dht_data_t

Data type for storing DHT sensor readings.

uint16_t humidity

relative deca-humidity

uint16_t temperature

temperature in deca-Celsius

struct dht_t

Device descriptor for DHT sensor devices.

gpio.h::gpio_t pin

GPIO pin of the device’s data pin.

dht.h::dht_type_t type

type of the DHT device

cc2538/include/periph_cpu.h::gpio_mode_t in_mode

input pin configuration, with or without pull resistor