Quick and dirty ble advetiment

code/parasite/lib/parasite/ble.cpp

@@ -1,5 +0,0 @@
-#include "ble.h"
-
-#include "ble_advdata.h"
-#include "nrf_sdh.h"
-#include "nrf_sdh_ble.h"

code/parasite/lib/parasite/parasite/ble.cpp

@@ -0,0 +1 @@
+#include "ble.h"

code/parasite/lib/parasite/parasite/ble.h

@@ -8,7 +8,7 @@ namespace parasite {
 class BLEAdvertiser {
  public:
   void Advertise(std::string name, double moisture) {}
-}
+};
 
 }  // namespace parasite
 #endif  // _PARASITE_BLE_H_

code/parasite/platformio.ini

@@ -8,14 +8,12 @@
 ; Please visit documentation for the other options and examples
 ; https://docs.platformio.org/page/projectconf.html
 
-[common]
-lib_deps = sandeepmistry/BLEPeripheral@^0.4.0
 
 [env:e73-tbb]
 platform = nordicnrf52
 board = adafruit_feather_nrf52832
 framework = arduino
-build_flags = -DNRF52 -DS132 -DNRF51_S132
+; build_flags = -DNRF52 -DS132 -DNRF51_S132 -DNRF5
 
 ; Let's keep it simple for now and just use adafruit_feather_nrf52832.
 ; board = e73-tbb

code/parasite/src/main.cpp

@@ -1,9 +1,9 @@
 #include <Arduino.h>
 
-// #include "ble.h"
-#include "pwm.h"
+#include "parasite/pwm.h"
+#include "parasite/ble.h"
 
-#include "nrf_sdh_ble.h"
+#include <bluefruit.h>
 
 constexpr int kLED1Pin = 17;
 constexpr int kLED2Pin = 18;
@@ -12,22 +12,30 @@ constexpr int kSensAnalogPin = 4;  // AIN2
 constexpr int kDischargeEnablePin = 16;
 constexpr double kPWMFrequency = 500000;
 
-// static void ble_stack_init(void) {
-//   ret_code_t err_code;
+char manufacturer_data[] = {
+  0x01,
+  0x02,
+  0x03,
+};
 
-//   err_code = nrf_sdh_enable_request();
-//   APP_ERROR_CHECK(err_code);
+constexpr int kManufacturerDataLen = 3;
 
-//   // Configure the BLE stack using the default settings.
-//   // Fetch the start address of the application RAM.
-//   uint32_t ram_start = 0;
-//   err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
-//   APP_ERROR_CHECK(err_code);
+void setupAdvertising() {
+  Bluefruit.begin(1, 1);
+  Bluefruit.setName("Parasite");
+}
 
-//   // Enable BLE stack.
-//   err_code = nrf_sdh_ble_enable(&ram_start);
-//   APP_ERROR_CHECK(err_code);
-// }
+void updateAdvertisingData(int moisture_level) {
+  manufacturer_data[2] = moisture_level & 0xff;
+  manufacturer_data[1] = 0xff;
+  Bluefruit.Advertising.stop();
+  Bluefruit.Advertising.clearData();
+  Bluefruit.Advertising.addName();
+  Bluefruit.Advertising.addManufacturerData(manufacturer_data, kManufacturerDataLen);
+  Bluefruit.Advertising.setInterval(32, 244);  // in unit of 0.625 ms
+  Bluefruit.Advertising.setFastTimeout(30);    // number of seconds in fast mode
+  Bluefruit.Advertising.start(0);  // 0 = Don't stop advertising after n seconds
+}
 
 void setup() {
   Serial.begin(9600);
@@ -37,11 +45,18 @@ void setup() {
   digitalWrite(kDischargeEnablePin, HIGH);
 
   analogReference(AR_VDD4);
+
+  setupAdvertising();
+  // Bluefruit.Advertising.start();
+
+  // ble.setConnectable(false);
+  // ble.addLocalAttribute();
 }
 
 void loop() {
   int sens_val = analogRead(kSensAnalogPin);
   Serial.printf("Val: %d\n", sens_val);
   digitalToggle(kLED1Pin);
+  updateAdvertisingData(sens_val);
   delay(500);
-}
+}

resources.md

@@ -142,7 +142,50 @@ I'm getting ~680 when in the air; ~65 while holding the sensor. The default reso
 
 # BLE
 * BLE examples for platformio with nordicnrf52 platform: [link](https://github.com/platformio/platform-nordicnrf52/tree/master/examples)
-* [BLEPeripheral](https://github.com/sandeepmistry/arduino-BLEPeripheral) seems to be a popular library choice
 * [nrf5 BLE examples](https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-advertising-a-beginners-tutorial) are way more complicated than I need for now
+* How the alternative firmware for the xiaomi temp sensor works: [link](https://github.com/atc1441/ATC_MiThermometer)
+  * The MCU is a [Telink TLSR8251](http://wiki.telink-semi.cn/doc/ds/DS_TLSR8251-E_Datasheet%20for%20Telink%20BLE+IEEE802.15.4%20Multi-Standard%20Wireless%20SoC%20TLSR8251.pdf)
+  * Deep sleep current is 1-2uA
+  * It sends an _advertisement packet_ every 1 minute with the MAC, temperature, humidity and battery level
+  * [main](https://github.com/atc1441/ATC_MiThermometer/blob/master/ATC_Thermometer/main.c)
+  * [main_loop](https://github.com/atc1441/ATC_MiThermometer/blob/916cef7db24977ec187e68ab6e718b7b7a4988e6/ATC_Thermometer/app.c#L76)
+  * [advertisement_data](https://github.com/atc1441/ATC_MiThermometer/blob/master/ATC_Thermometer/ble.c#L39) definition
+  * [set_adv_data](https://github.com/atc1441/ATC_MiThermometer/blob/master/ATC_Thermometer/ble.c#L178) - where the temp, humidity and batt levels are encoded into the advertisement data
+* How the xiaomi BLE temp sensor works in ESPHome: [link](https://github.com/esphome/esphome/blob/5c86f332b269fd3e4bffcbdf3359a021419effdd/esphome/components/xiaomi_lywsd03mmc/xiaomi_lywsd03mmc.cpp)
+* [How advertisement works YouTube video](https://www.youtube.com/watch?v=CJcLabp42b4) by nordic
+  * In your case:
+    * GAP role: broadcaster
+    * Advertisement type: legacy ADV_NONCONN_IND (non-connectable broadcast)
+    * Advertising data starts at 22:17
+      * The payload might contain 37 bytes in the classic/legacy protocol:
+        * addr (6 bytes) (either public or random)
+          * Public has privacy concerns
+          * Random can be static or private (resolvable or non-resolvable)
+        * data (31 bytes)
+    * The 31 bytes of advertisement data can be split into structures
+      * Each structure has a length (1 byte), a type (n bytes) and data (remaining bytes)
+      * Examples of structures are service UUID, local name, manufacturer specific data
+      * Manufacturer specific data is usually the way to transmit data in the advertisement packet
+        * Requires a company id. Check out the [list](https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers). Adafruit has the 0x0822.
+* [BLEPeripheral](https://github.com/sandeepmistry/arduino-BLEPeripheral) seems to be a popular library choice
+  * [setManufacturerData](https://github.com/sandeepmistry/arduino-BLEPeripheral/blob/161a4163f565be3cd5b62bbc59f0c2b522d82b02/src/BLEPeripheral.h#L72) is probably what we want
+  * It seems to be highly geared towards nrf51 SOCs, although it mentions support for some nrf52 ones
+* [Adafruit_nRF52_Arduino](https://github.com/adafruit/Adafruit_nRF52_Arduino)
+  * [BLEAdvertising guide](https://learn.adafruit.com/bluefruit-nrf52-feather-learning-guide/bleadvertising)
+    * [BLEAdvertising.h](https://github.com/adafruit/Adafruit_nRF52_Arduino/blob/master/libraries/Bluefruit52Lib/src/BLEAdvertising.h#L87)
+* Can we update the manufaturer advertising data dynamically?
+  * [Hint on devzone.nordicsemi.com](https://devzone.nordicsemi.com/f/nordic-q-a/11217/adc-values-in-advertising-data-dynamically-changing)
 
-# OTA
+# Central BLE
+The "central" BLE will be responsible for listening to parasite's BLE broadcasts and parsing its manufacturer's data.
+One idea is to use ESPHome for this, for example like the xiaomi sensor does:
+* [Xiaomi component's parse_device](https://github.com/esphome/esphome/blob/dev/esphome/components/xiaomi_lywsd03mmc/xiaomi_lywsd03mmc.cpp#L19)
+* [esp32_ble_tracker calls all registered parse_devices()](https://github.com/esphome/esphome/blob/dev/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp#L68)
+* [Setting up the development environment for ESPHome](https://esphome.io/guides/contributing.html#setting-up-development-environment)
+
+Question: parasite will advertise a _lot_ of packets in short bursts. How is this data "deduplicated"? I imagine ESPHome won't parse all the packets and forward them to MQTT.
+
+# OTA
+
+# Measuring current consumption
+* Good [issue](https://github.com/atc1441/ATC_MiThermometer/issues/134) on the xiaomi sensor tracker