Collect data from bosh/sparkfun BME280 & Si7021 over i2c and the internal esp32 temperature sensor. Send data to thingspeak.com and go back to sleep.
Here are the reuslts. https://thingspeak.com/channels/209116 https://thingspeak.com/channels/212260 For the first dataseries I opened the window, closed the window, used a hair-drier and then just let is sit with the window closed. For the second channel I put the esp32 in a box that I placed outside.
I also solved the problem with bootcount being lost during sleep.
esp_deep_sleep_pd_config(ESP_PD_DOMAIN_RTC_SLOW_MEM, ESP_PD_OPTION_ON);
That statement was missing in the 06_sntp example. Now I will let the board run on a 7800mAh battery and continue to update this thingspeak channel https://thingspeak.com/channels/212260 I also added pressure to this feed. As measurements indoors wasnt so exciting I moved the data collection outside.
For temperature measurements, I used the adafruit si7021 temperature humidity board & Sparkfun BME280 board.
https://cdn-learn.adafruit.com/assets/assets/000/035/931/original/Support_Documents_TechnicalDocs_Si7021-A20.pdf
Both are i2c boards, here is the output when running.
The esp32 will wakeup every 6 seconds and check the boot_count. This is done as otherwise the battery will switch off. Every minute wifi will be started and the collected data will be logged on http://thingspeak.com
#i2c_init Before the modules can be used, this must be called.
/**
* @brief i2c master initialization
*/
void i2c_init()
{
int i2c_master_port = I2C_MASTER_NUM;
i2c_config_t conf;
conf.mode = I2C_MODE_MASTER;
conf.sda_io_num = I2C_MASTER_SDA_IO;
conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
conf.scl_io_num = I2C_MASTER_SCL_IO;
conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
i2c_param_config(i2c_master_port, &conf);
i2c_driver_install(i2c_master_port, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
}
#i2c_scan Simple but useful to see the assigned adresses of the i2c devices.
/**
* _____________________________
* | start | slave_addr + sack |
* --------|--------------------|
*
*/
esp_err_t i2c_master_check_slave(i2c_port_t i2c_num,uint8_t addr)
{
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, ( addr << 1 ) , ACK_CHECK_EN);
i2c_master_stop(cmd);
esp_err_t ret = i2c_master_cmd_begin(i2c_num, cmd, 1000 / portTICK_RATE_MS);
i2c_cmd_link_delete(cmd);
return ret;
}
void i2c_scan() {
int address;
int ret;
int foundCount = 0;
for (address=1; address<127; address++) {
ret=i2c_master_check_slave(I2C_MASTER_NUM,address);
if (ret == ESP_OK) {
printf("Found device addres: %02x\n", address);
foundCount++;
}
}
printf("Done scanning.. found %d devices\n",foundCount);
}
#The si7021 board https://cdn-learn.adafruit.com/downloads/pdf/adafruit-si7021-temperature-plus-humidity-sensor.pdf Future enhancements could be to add heating function to enhance humidity sensing.
i7021.humidity=i2c_7021_read_rh();
i7021.temp=i2c_7021_read_temp();
#The BME280 weather data board https://github.com/sparkfun/SparkFun_BME280_Arduino_Library https://github.com/BoschSensortec/BME280_driver To save battery, we use this sensor in forced mode. i2c_bme280_begin(); puts the sensor in normal run mode. After calling i2c_bme280_force_readings(); the sensor does one measurement and then goes back to sleep mode. (0)
i2c_bme280_begin();
i2c_bme280_force_readings();
bme280.temp=i2c_bme280_read_temp();
pressure=i2c_bme280_read_pressure();
bme280.humidity=i2c_bme280_read_rh();
printf("RH %d Temp %d , pressure %f\n",bme280.humidity,bme280.temp,pressure/100.0);
printf("power mode %x\n",i2c_bme280_get_power_mode());
Running all day
and night
