diff --git a/main/squeeze.c b/main/squeeze.c
new file mode 100644
--- /dev/null
+++ b/main/squeeze.c
@@ -0,0 +1,78 @@
+#include "driver/adc.h"
+#include "esp_adc_cal.h"
+#include "esp_log.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+
+#include "squeeze.h"
+
+static const char *TAG = "squeeze";
+
+esp_adc_cal_characteristics_t adc1_chars;
+
+// Private prototypes
+static void squeeze_process(void);
+
+
+void squeeze_init(void)
+{
+    // ADC1 chan0 is PIN1
+    adc1_config_channel_atten(ADC1_CHANNEL_0, ADC_ATTEN_DB_12);
+    esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_12, ADC_WIDTH_BIT_DEFAULT, 0, &adc1_chars);
+    xTaskCreatePinnedToCore(squeeze_process, "squeeze", 1024*2, NULL, 10, NULL, 1);
+}
+
+
+// Definitions
+#define ALPHA_FAST 0.02f
+#define ALPHA_SLOW 0.005f
+
+// Private variables
+static float reading_fast = 0.0f;
+static float reading_slow = 0.0f;
+static float delta_last = 0.0f;
+static uint8_t triggered_flag = 0;
+
+
+static void squeeze_process(void)
+{
+    for(;;)
+    {
+        uint32_t millivolts = esp_adc_cal_raw_to_voltage(adc1_get_raw(ADC1_CHANNEL_0), &adc1_chars);
+
+        reading_fast = (ALPHA_FAST * millivolts) + ((1.0-ALPHA_FAST) * reading_fast);
+        reading_slow = (ALPHA_SLOW * millivolts) + ((1.0-ALPHA_SLOW) * reading_slow);
+        float delta = reading_fast - reading_slow;
+
+        //ESP_LOGI(TAG, "ADC read %lu fast=%g slow=%g delta=%g", millivolts, reading_fast, reading_slow, delta);
+
+        if(delta > 4.0 && delta_last < 4.0)
+        {
+            ESP_LOGI(TAG, "Trigger at delta %g", delta);
+
+            // set flag, consumed on read by squeeze_triggered()
+            triggered_flag = 1;
+        }
+        delta_last = delta;
+        vTaskDelay(10 / portTICK_PERIOD_MS);
+    }
+}
+
+float squeeze_value(void)
+{
+    return reading_fast;
+}
+
+uint8_t squeeze_triggered(void)
+{
+    if(triggered_flag == 1)
+    {
+        // consume
+        triggered_flag = 0;
+        return 1;
+    }
+    else
+    {
+        return 0;
+    }
+}
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