diff --git a/ch32v-insert-coin/src/app.rs b/ch32v-insert-coin/src/app.rs
index c48a073..4cc0dd7 100644
--- a/ch32v-insert-coin/src/app.rs
+++ b/ch32v-insert-coin/src/app.rs
@@ -301,6 +301,7 @@ pub struct Sequences {
 // things that touch hardware
 pub struct Interfaces {
     pub pwm_core: SimplePwmCore<'static, ch32_hal::peripherals::TIM1>,
+    pub adc_core: crate::AdcCore,
 }
 
 pub struct App {
@@ -388,8 +389,12 @@ impl App {
         }
         if self.timers.batt_adc_timer.need_service() {
             self.timers.batt_adc_timer.service();
+            let bv = self.interfaces.adc_core.get_battery_voltage();
             #[cfg(feature = "enable_print")]
-            println!("batt adc service");
+            println!("batt adc service: {bv}");
+
+            // TODO:
+            // do stuff if the battery voltage is below some threshold
         }
         if self.timers.usb_adc_timer.need_service() {
             self.timers.usb_adc_timer.service();
diff --git a/ch32v-insert-coin/src/main.rs b/ch32v-insert-coin/src/main.rs
index 1e9e74c..d8dc81d 100644
--- a/ch32v-insert-coin/src/main.rs
+++ b/ch32v-insert-coin/src/main.rs
@@ -44,6 +44,30 @@ use crate::app::sequencer::{DynamicSequence, SequenceEntry};
 
 static LED0_SEQ: [u8; 8] = [0u8, 25u8, 50u8, 75u8, 100u8, 75u8, 50u8, 25u8];
 
+use hal::adc::Adc;
+use hal::peripherals::{ADC1, PD4};
+
+pub struct AdcCore {
+    adc: Adc<'static, ADC1>,
+    battery_pin: PD4,
+}
+
+impl AdcCore {
+    pub fn new(mut adc: Adc<'static, ADC1>, pin: PD4) -> Self {
+        adc.calibrate();
+        Self {
+            adc,
+            battery_pin: pin,
+        }
+    }
+
+    // TODO make this a float or something
+    pub fn get_battery_voltage(&mut self) -> u16 {
+        self.adc
+            .convert(&mut self.battery_pin, hal::adc::SampleTime::CYCLES241)
+    }
+}
+
 #[derive(Debug)]
 struct Flag {
     value: bool,
@@ -205,13 +229,13 @@ fn app_main(mut p: hal::Peripherals) -> ! {
     // adc
     let mut adc = hal::adc::Adc::new(p.ADC1, Default::default());
     let mut batt_monitor_pin = p.PD4;
+    let adc_core = AdcCore::new(adc, batt_monitor_pin);
 
     // adc2
     // let mut usb_detect_dc = hal::adc::Adc::new(p.ADC1, Default::default());
     let mut usb_detect_pin = p.PD5;
 
     // println!("ADC_PIN CHANNEL: {}", adc_pin.channel().channel());
-    let adc_cal = adc.calibrate();
 
     // #[cfg(feature = "enable_print")]
     // println!("ADC calibration value: {}", adc_cal);
@@ -289,7 +313,7 @@ fn app_main(mut p: hal::Peripherals) -> ! {
         audio: &SEQUENCE_LIST,
     };
 
-    let app_interfaces = Interfaces { pwm_core };
+    let app_interfaces = Interfaces { pwm_core, adc_core };
 
     let mut app = App::new(app_config, app_services, app_sequences, app_interfaces);