From 48d8ef95d6242e404633e9b6598b8f14986fb60c Mon Sep 17 00:00:00 2001
From: Clara Dautermann <git@cdaut.de>
Date: Fri, 11 Jul 2025 21:12:55 +0200
Subject: [PATCH] probably got ADC for NO2 sensor working??

---
 firmware/src/main.rs | 93 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 76 insertions(+), 17 deletions(-)

diff --git a/firmware/src/main.rs b/firmware/src/main.rs
index 7f4a996..15d2cfe 100644
--- a/firmware/src/main.rs
+++ b/firmware/src/main.rs
@@ -1,11 +1,46 @@
-use bme280::i2c::BME280;
+use bme280::{i2c::BME280, Error};
 use esp_idf_hal::{
+    adc::{
+        attenuation,
+        oneshot::{config::AdcChannelConfig, AdcChannelDriver, AdcDriver},
+        ADC2,
+    },
     delay::Delay,
-    i2c::{I2cConfig, I2cDriver},
+    i2c::{I2cConfig, I2cDriver, I2cError},
     prelude::Peripherals,
 };
 
+struct InitResult<'s, I2C> {
+    bme280: BME280<I2C>,
+    no2_adc: AdcChannelDriver<'s, esp_idf_hal::gpio::Gpio4, AdcDriver<'s, ADC2>>,
+}
+
 fn main() {
+    let mut peripherals = init();
+
+    loop {
+        let measurement = peripherals
+            .bme280
+            .measure(&mut Delay::new_default())
+            .unwrap();
+
+        println!(
+            "temperature:{0}°C, pressure:{1}",
+            measurement.temperature, measurement.pressure
+        );
+
+        match peripherals.no2_adc.read() {
+            Ok(v) => {
+                println!("NO2 ADC voltage: {v}");
+            }
+            Err(err) => log::error!("Failed to read ADC for NO2 value with error {err}"),
+        };
+
+        Delay::default().delay_ms(1000);
+    }
+}
+
+fn init<'a>() -> InitResult<'a, I2cDriver<'a>> {
     //set up logger
     esp_idf_sys::link_patches(); // Important!
     esp_idf_svc::log::EspLogger::initialize_default();
@@ -47,7 +82,45 @@ fn main() {
         Ok(_) => {}
         Err(err) => {
             log::error!("Error initializing bme280 sensor:");
-            match err {
+            handle_i2c_error(err);
+        }
+    }
+    log::info!("BME280 up!");
+
+    //initialize adc2 for MICS2714
+    let adc2 = match AdcDriver::new(peripherals.adc2) {
+        Ok(driver) => driver,
+        Err(err) => {
+            log::error!("Failed to initialize AdcDriver with error {err}");
+            panic!()
+        }
+    };
+
+    log::info!("Initializing ADC2 on GPIO4 for NO2 sensor…");
+
+    // Define channel config with desired attenuation
+    let mut channel_config = AdcChannelConfig::new();
+    channel_config.attenuation = attenuation::DB_11;
+
+    let adc_channel_driver: AdcChannelDriver<'a, esp_idf_hal::gpio::Gpio4, AdcDriver<'_, ADC2>> =
+        match AdcChannelDriver::new(adc2, peripherals.pins.gpio4, &channel_config) {
+            Ok(channel) => channel,
+            Err(err) => {
+                log::error!("Failed to initialize AdcChannelDriver with error {err}");
+                panic!()
+            }
+        };
+
+    log::info!("ADC2  channel driver@GPIO4 initialized!");
+
+    InitResult {
+        bme280: bme280,
+        no2_adc: adc_channel_driver,
+    }
+}
+
+fn handle_i2c_error(error: Error<I2cError>) {
+    match error {
                 bme280::Error::CompensationFailed => log::error!("Failed to compensate a raw measurement"),
                 bme280::Error::Bus(buserr) => log::error!("Bus error: {}", buserr),
                 bme280::Error::InvalidData => log::error!("Failed to pare sensor data!"),
@@ -55,18 +128,4 @@ fn main() {
                 bme280::Error::UnsupportedChip =>  log::error!("Chip ID doesn't match expected value"),
                 bme280::Error::Delay => log::error!("Delay error"),
             }
-        }
-    }
-    log::info!("BME280 up!");
-
-    loop {
-        let measurement = bme280.measure(&mut Delay::new_default()).unwrap();
-
-        println!(
-            "1：temperature:{0}°C, pressure:{1}",
-            measurement.temperature, measurement.pressure
-        );
-
-        Delay::default().delay_ms(1000);
-    }
 }