How to: Soil Sensor

Soil Moisture sensor measures moisture and temperature. See also About Soil Moisture Sensor article.

Writing a single sensor values to the console

This is the simplest example with single connected sensor to the Sensor Module.

 1#include <application.h>
 2
 3// Soil sensor instance
 4twr_soil_sensor_t soil_sensor;
 5
 6void soil_sensor_event_handler(twr_soil_sensor_t *self, uint64_t device_address, twr_soil_sensor_event_t event, void *event_param)
 7{
 8    if (event == TWR_SOIL_SENSOR_EVENT_UPDATE)
 9    {
10        uint16_t moisture;
11        float temperature;
12
13        twr_soil_sensor_get_cap_raw(self, device_address, &moisture);
14        twr_soil_sensor_get_temperature_celsius(self, device_address, &temperature);
15        twr_log_debug("Moisture: %d\tTemperature %.2f", moisture, temperature);
16    }
17}
18
19void application_init(void)
20{
21    twr_log_init(TWR_LOG_LEVEL_DUMP, TWR_LOG_TIMESTAMP_ABS);
22
23    // Initialize soil sensor
24    twr_soil_sensor_init(&soil_sensor);
25    twr_soil_sensor_set_event_handler(&soil_sensor, soil_sensor_event_handler, NULL);
26    twr_soil_sensor_set_update_interval(&soil_sensor, 1000);
27}

Multiple connected sensors

When you connect multiple sensors, you need to initialize them with twr_soil_sensor_init_multiple. In the event handler you then get the device_address in the callback parameter, or you can get sensor index by calling twr_soil_sensor_get_index_by_device_address().

 1#define MAX_SOIL_SENSORS                    5
 2
 3// Sensors array
 4twr_soil_sensor_sensor_t sensors[MAX_SOIL_SENSORS];
 5
 6void soil_sensor_event_handler(twr_soil_sensor_t *self, uint64_t device_address, twr_soil_sensor_event_t event, void *event_param)
 7{
 8    ...
 9    if (event == TWR_SOIL_SENSOR_EVENT_UPDATE)
10    {
11        int index = twr_soil_sensor_get_index_by_device_address(self, device_address);
12    ...
13}
14
15void application_init(void)
16{
17    ...
18
19    // Initialize soil sensors
20    twr_soil_sensor_init_multiple(&soil_sensor, sensors, MAX_SOIL_SENSORS);
21    twr_soil_sensor_set_event_handler(&soil_sensor, soil_sensor_event_handler, NULL);
22    twr_soil_sensor_set_update_interval(&soil_sensor, SENSOR_UPDATE_SERVICE_INTERVAL);
23
24    ...
25}