From c9b05859e46881c2604f68f8706b44a0b2fb696e Mon Sep 17 00:00:00 2001
From: chentadot <69039534+chentadot@users.noreply.github.com>
Date: Mon, 5 Jul 2021 21:59:39 +0300
Subject: [PATCH] First draft for Photoresistor

the code now should setup and use the photoresistor and read it's value by the adc.
the returned value is 0 just as a place holder until the correct values are measured.
---
 code/b-parasite/config/prst_config.h |  4 ++++
 code/b-parasite/src/main.c           |  7 ++++++-
 code/b-parasite/src/prst/adc.c       | 29 ++++++++++++++++++++++++++++
 code/b-parasite/src/prst/adc.h       |  8 ++++++++
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/code/b-parasite/config/prst_config.h b/code/b-parasite/config/prst_config.h
index 6b77478..3c52b5f 100644
--- a/code/b-parasite/config/prst_config.h
+++ b/code/b-parasite/config/prst_config.h
@@ -6,6 +6,10 @@
 // Built-in LED.
 #define PRST_LED_PIN NRF_GPIO_PIN_MAP(0, 28)
 
+// Photo Sensor
+#define PRST_PHOTO_V NRF_GPIO_PIN_MAP(1, 11)
+#define PRST_PHOTO_OUT NRF_GPIO_PIN_MAP(0, 2)
+
 // Deep sleep.
 #define PRST_DEEP_SLEEP_IN_SECONDS 300
 
diff --git a/code/b-parasite/src/main.c b/code/b-parasite/src/main.c
index dccd4bc..25d6759 100644
--- a/code/b-parasite/src/main.c
+++ b/code/b-parasite/src/main.c
@@ -62,8 +62,13 @@ static void rtc_callback() {
   prst_adc_soil_moisture_t soil_read = prst_adc_soil_read(batt_read.voltage);
   prst_pwm_stop();
   nrf_gpio_pin_clear(PRST_FAST_DISCH_PIN);
+
+  nrf_gpio_pin_set(PRST_PHOTO_V);                                         // set GPIO for photoresistor HIGH
+  prst_adc_photo_sensor prst_adc_photo_read(double battery_voltage);      // read PHOTO SENSOR value
+  nrf_gpio_pin_clear(PRST_PHOTO_V);                                       // not sure need this one
+
   prst_ble_update_adv_data(batt_read.millivolts, temp_humi.temp_millicelcius,
-                           temp_humi.humidity, soil_read.relative, run_counter);
+                           temp_humi.humidity, soil_read.relative, prst_adc_photo_sensor.lux, run_counter);
   prst_adv_start();
   nrf_delay_ms(PRST_BLE_ADV_TIME_IN_MS);
   prst_adv_stop();
diff --git a/code/b-parasite/src/prst/adc.c b/code/b-parasite/src/prst/adc.c
index 025fbb8..666b66d 100644
--- a/code/b-parasite/src/prst/adc.c
+++ b/code/b-parasite/src/prst/adc.c
@@ -17,6 +17,9 @@
 #define PRST_ADC_SOIL_INPUT NRF_SAADC_INPUT_AIN1
 #define PRST_ADC_SOIL_CHANNEL 1
 
+#define PRST_ADC_PHOTO_INPUT NRF_SAADC_INPUT_AIN0
+#define PRST_ADC_PHOTO_CHANNEL 2
+
 static nrf_saadc_value_t sample_adc_channel(uint8_t channel) {
   nrf_saadc_value_t result;
   // *WARNING* this function is blocking, which is ot ideal but okay, but it
@@ -64,6 +67,12 @@ void prst_adc_init() {
 
   APP_ERROR_CHECK(
       nrf_drv_saadc_channel_init(PRST_ADC_SOIL_CHANNEL, &soil_channel_config));
+
+  nrf_saadc_channel_config_t photo_channel_config =
+      NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(PRST_ADC_PHOTO_INPUT);
+
+  APP_ERROR_CHECK(
+      nrf_drv_saadc_channel_init(PRST_ADC_PHOTO_CHANNEL, &photo_channel_config));
 }
 
 prst_adc_batt_read_t prst_adc_batt_read() {
@@ -118,5 +127,25 @@ prst_adc_soil_moisture_t prst_adc_soil_read(double battery_voltage) {
                " %% (percentage); %u (relative)",
                ret.raw, NRF_LOG_FLOAT(percentage * 100), ret.relative);
 #endif
+  return ret;
+}
+
+static inline double get_lux_level(double battery_voltage, nrf_saadc_value_t raw_adc_output) {
+  const double x = battery_voltage;
+
+  // todo: add DEBUG lines
+
+  return 0;   // place holder. need to map values to lux level.
+}
+
+prst_adc_photo_sensor prst_adc_photo_read(double battery_voltage) {
+  nrf_saadc_value_t raw_adc_output = sample_adc_channel(PRST_ADC_PHOTO_CHANNEL);
+  const uint16_t lux = get_lux_level(battery_voltage, raw_adc_output);
+  prst_adc_photo_sensor ret;
+  ret.raw = raw_adc_output;
+  ret.lux = lux;      
+
+  // todo: add DEBUG lines
+  
   return ret;
 }
\ No newline at end of file
diff --git a/code/b-parasite/src/prst/adc.h b/code/b-parasite/src/prst/adc.h
index 6b2bebe..9a0265a 100644
--- a/code/b-parasite/src/prst/adc.h
+++ b/code/b-parasite/src/prst/adc.h
@@ -16,10 +16,18 @@ typedef struct prst_adc_soil_moisture {
   double percentage;
 } prst_adc_soil_moisture_t;
 
+typedef struct prst_adc_photo_sensor {
+  int16_t raw;
+  // Should check minimum and maximum values
+  uint16_t lux;
+} prst_adc_photo_sensor;
+
 void prst_adc_init();
 
 prst_adc_batt_read_t prst_adc_batt_read();
 
 prst_adc_soil_moisture_t prst_adc_soil_read(double battery_voltage);
 
+prst_adc_photo_sensor prst_adc_photo_read(double battery_voltage);
+
 #endif  // _PRST_ADC_H_
\ No newline at end of file