-#define AMBIENT_ADC N_PWMLEDS
-#define BATTERY_ADC (N_PWMLEDS + 1)
-#define ADC1_GAIN20 (N_PWMLEDS + 2)
-#define BUTTON_ADC (N_PWMLEDS + 3)
-#define ZERO_ADC (N_PWMLEDS + 4)
+// pwmleds are measured continuously (when active)
+#define AMBIENT_ADC N_PWMLEDS // measured every jiffy (16 Hz)
+#define BUTTON_ADC (N_PWMLEDS + 1) // measured every jiffy (16 Hz)
+#define FIRST_16HZ_ADC BUTTON_ADC
+#define BATTERY_ADC (N_PWMLEDS + 2) // once per second
+#define ADC1_GAIN20 (N_PWMLEDS + 3) // once per second
+#define FIRST_1S_ADC ADC1_GAIN20
+#define ZERO_ADC (N_PWMLEDS + 4) // must be last