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Merge pull request #53 from rbaron/bthome

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Adds support for the BTHome BLE protocol
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rbaron 2022-08-29 21:35:27 +02:00 • committed by GitHub
commit 5c1ea4a164
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5 changed files with 135 additions and 50 deletions
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12
code/b-parasite/config/prst_config.h
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@ -27,9 +27,15 @@
// BLE.
// Prints out BLE debug info, such as the final encoded advertisement packet.
#define PRST_BLE_DEBUG 0
// The BLE protocol version defines how the sensors' data is encoded inside the
// BLE advertisement packet. Possible values are 1 and 2.
#define PRST_BLE_PROTOCOL_VERSION 1
// Supported BLE protocols.
// Default, custom BLE protocol.
#define PRST_BLE_PROTOCOL_BPARASITE_V2 0x01
// BTHome BLE protocol - https://bthome.io.
#define PRST_BLE_PROTOCOL_BTHOME 0x02
// Chosen BLE protocol.
#define PRST_BLE_PROTOCOL PRST_BLE_PROTOCOL_BPARASITE_V2
// There are two options for configuring the MAC address of b-parasites:
// 1. Comment out the PRST_BLE_MAC_ADDR to use a random static MAC address that

14
code/b-parasite/src/main.c
View file

@ -9,6 +9,7 @@
#include "nrf_pwr_mgmt.h"
#include "prst/adc.h"
#include "prst/ble.h"
#include "prst/data.h"
#include "prst/pwm.h"
#include "prst/rtc.h"
#include "prst/shtc3.h"
@ -86,9 +87,16 @@ static void rtc_callback() {
nrf_gpio_pin_clear(PRST_PHOTO_V_PIN);
#endif
prst_ble_update_adv_data(batt_read.millivolts, temp_humi.temp_celsius,
temp_humi.humidity, soil_read.relative, lux,
run_counter);
prst_sensor_data_t sensors = {
.batt_mv = batt_read.millivolts,
.temp_c = temp_humi.temp_celsius,
.humi = temp_humi.humidity,
.soil_moisture = soil_read.relative,
.lux = lux,
.run_counter = run_counter,
};
prst_ble_update_adv_data(&sensors);
state = ADVERTISING;
prst_adv_start();

138
code/b-parasite/src/prst/ble.c
View file

@ -3,16 +3,13 @@
#include <ble_advdata.h>
#include <ble_gap.h>
#include <nordic_common.h>
#include <nrf_delay.h>
#include <nrf_log.h>
#include <nrf_sdh.h>
#include <nrf_sdh_ble.h>
#include "prst_config.h"
// We need to pick a service UUID for broadcasting our sensor data.
// 0x181a is defined as "environmental sensing", which seems appopriate.
#define SERVICE_UUID 0x181a
// The connection to configure. We only have the one.
#define PRST_CONN_CFG_TAG 1
@ -46,7 +43,16 @@ whether or not they have added the LDR by setting the PRST_HAS_LDR to 1 in
prst_config.h.
*/
#if PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BPARASITE_V2
#define SERVICE_UUID 0x181a
#define SERVICE_DATA_LEN 18
#elif PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BTHOME
#define SERVICE_UUID 0x181c
#define SERVICE_DATA_LEN 16
#else
#error "PRST_BLE_PROTOCOL is not properly configured"
#endif
static uint8_t service_data[SERVICE_DATA_LEN];
// Stores the encoded advertisement data. As per BLE spec, 31 bytes max.
@ -112,26 +118,12 @@ static void init_advertisement_data() {
ble_gap_conn_sec_mode_t sec_mode;
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
sd_ble_gap_device_name_set(&sec_mode, (const uint8_t *)PRST_BLE_ADV_NAME,
sd_ble_gap_device_name_set(&sec_mode, (const uint8_t*)PRST_BLE_ADV_NAME,
strlen(PRST_BLE_ADV_NAME));
uint32_t err_code =
sd_ble_gap_adv_set_configure(&adv_handle_, &gap_adv_data_, &adv_params_);
APP_ERROR_CHECK(err_code);
// Four bits for the protocol version.
service_data[0] |= (PRST_BLE_PROTOCOL_VERSION << 4) & 0xf0;
// Bit 0 of byte 0 specifies whether or not ambient light data exists in the
// payload.
#if PRST_HAS_LDR || PRST_HAS_PHOTOTRANSISTOR
service_data[0] |= 1;
#endif
// Bytes 10-15 (inclusive) contain the whole MAC address in big-endian.
for (int i = 0; i < 6; i++) {
service_data[10 + i] = gap_addr_.addr[5 - i];
}
}
void prst_ble_init() {
@ -169,37 +161,100 @@ void prst_ble_init() {
init_advertisement_data();
}
void prst_ble_update_adv_data(uint16_t batt_millivolts, float temp_celsius,
uint16_t humidity, uint16_t soil_moisture,
uint16_t brightness, uint8_t run_counter) {
#if PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BPARASITE_V2
static void set_service_data_bparasite_protocol(
const prst_sensor_data_t* sensors) {
// Four bits for the protocol version.
service_data[0] |= (2 << 4) & 0xf0;
// Bit 0 of byte 0 specifies whether or not ambient light data exists in the
// payload.
#if PRST_HAS_LDR || PRST_HAS_PHOTOTRANSISTOR
service_data[0] |= 1;
#endif
// 4 bits for a small wrap-around counter for deduplicating messages on the
// receiver.
service_data[1] = run_counter & 0x0f;
service_data[1] = sensors->run_counter & 0x0f;
service_data[2] = batt_millivolts >> 8;
service_data[3] = batt_millivolts & 0xff;
service_data[2] = sensors->batt_mv >> 8;
service_data[3] = sensors->batt_mv & 0xff;
#if PRST_BLE_PROTOCOL_VERSION == 1
uint16_t temp_millicelsius = temp_celsius * 1000;
service_data[4] = temp_millicelsius >> 8;
service_data[5] = temp_millicelsius & 0xff;
#elif PRST_BLE_PROTOCOL_VERSION == 2
int16_t temp_centicelsius = temp_celsius * 100;
int16_t temp_centicelsius = 100 * sensors->temp_c;
service_data[4] = temp_centicelsius >> 8;
service_data[5] = temp_centicelsius & 0xff;
#else
#error "[ble] Unsupported BLE protocol version"
#endif // PRST_BLE_PROTOCOL_VERSION
service_data[6] = humidity >> 8;
service_data[7] = humidity & 0xff;
service_data[6] = sensors->humi >> 8;
service_data[7] = sensors->humi & 0xff;
service_data[8] = soil_moisture >> 8;
service_data[9] = soil_moisture & 0xff;
service_data[8] = sensors->soil_moisture >> 8;
service_data[9] = sensors->soil_moisture & 0xff;
// Bytes 10-15 (inclusive) contain the whole MAC address in big-endian.
for (int i = 0; i < 6; i++) {
service_data[10 + i] = gap_addr_.addr[5 - i];
}
#if PRST_HAS_LDR || PRST_HAS_PHOTOTRANSISTOR
service_data[16] = brightness >> 8;
service_data[17] = brightness & 0xff;
service_data[16] = sensors->lux >> 8;
service_data[17] = sensors->lux & 0xff;
#endif
}
#endif // PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BPARASITE_V2
#if PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BTHOME
static void set_service_data_bthome_protocol(
const prst_sensor_data_t* sensors) {
// See values in https://bthome.io/.
// 1. Soil moisture.
// uint16_t.
service_data[0] = (0b000 << 5) | 2;
// Type of measurement - Moisture.
service_data[1] = 0x14;
// Value. Factor of 0.01, so we need to multiply our the value in 100% by
// 1/0.01 = 100.
uint16_t soil_val = (10000 * sensors->soil_moisture) / UINT16_MAX;
service_data[2] = soil_val & 0xff;
service_data[3] = soil_val >> 8;
// 2. Temp.
// int16_t.
service_data[4] = (0b001 << 5) | 2;
// Type of measurement - temperature.
service_data[5] = 0x02;
// Value. Factor 0.01.
int16_t temp_val = 100 * sensors->temp_c;
service_data[6] = temp_val & 0xff;
service_data[7] = temp_val >> 8;
// 3. Humidity
// uint16_t.
service_data[8] = (0b000 << 5) | 2;
// Type - humidity.
service_data[9] = 0x03;
// Value. Factor 0.01, over 100%.
uint16_t humi_val = (10000 * sensors->humi) / UINT16_MAX;
service_data[10] = humi_val & 0xff;
service_data[11] = humi_val >> 8;
// 4. Battery voltage.
// uint16_t.
service_data[12] = (0b000 << 5) | 2;
// Type - voltage.
service_data[13] = 0x0c;
// Value. Factor of 0.001.
uint16_t batt_val = sensors->batt_mv;
service_data[14] = batt_val & 0xff;
service_data[15] = batt_val >> 8;
}
#endif // PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BTHOME
void prst_ble_update_adv_data(const prst_sensor_data_t* sensors) {
#if PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BPARASITE_V2
set_service_data_bparasite_protocol(sensors);
#elif PRST_BLE_PROTOCOL == PRST_BLE_PROTOCOL_BTHOME
set_service_data_bthome_protocol(sensors);
#endif
// Encodes adv_data_ into .gap_adv_data_.
@ -210,7 +265,8 @@ void prst_ble_update_adv_data(uint16_t batt_millivolts, float temp_celsius,
#if PRST_BLE_DEBUG
NRF_LOG_INFO("[ble] Encoded BLE adv packet:");
for (int i = 0; i < sizeof(encoded_adv_data_); i++) {
NRF_LOG_INFO("[ble] 0x%02x", encoded_adv_data_[i]);
NRF_LOG_INFO("[ble] byte %02d: 0x%02x", i, encoded_adv_data_[i]);
nrf_delay_ms(50);
}
#endif
}

6
code/b-parasite/src/prst/ble.h
View file

@ -4,6 +4,8 @@
#include <app_error.h>
#include <stdint.h>
#include "prst/data.h"
// Initializes SoftDevice.
void prst_ble_init();
@ -11,8 +13,6 @@ void prst_adv_start();
void prst_adv_stop();
void prst_ble_update_adv_data(uint16_t batt_millivolts, float temp_celsius,
uint16_t humidity, uint16_t soil_moisture,
uint16_t brightness, uint8_t run_counter);
void prst_ble_update_adv_data(const prst_sensor_data_t* sensors);
#endif // _PRST_BLE_H_

15
code/b-parasite/src/prst/data.h Normal file
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@ -0,0 +1,15 @@
#ifndef _PRST_DATA_H_
#define _PRST_DATA_H_
#include <stdint.h>
typedef struct {
uint16_t batt_mv;
float temp_c;
uint16_t humi;
uint16_t soil_moisture;
uint16_t lux;
uint8_t run_counter;
} prst_sensor_data_t;
#endif // _PRST_DATA_H_