@@ -0,0 +30,4 @@
+void loop() {
+	const int32_t mv = averageMv();
+	if (mv >= supplyMv - openCircuitMarginMv) {
+		Serial.printf("%lu %ld open\n", millis(), static_cast<long>(mv));

@@ -0,0 +1,7 @@
+[env:xiao]

@@ -0,0 +28,4 @@
+
+void setup() {
+	Serial.begin(115200);
+	Serial.println("# ms mV ohms pct");

@@ -0,0 +1,49 @@
+// Bench probe for a 0 to 190 ohm tank level sender. 3V3 to a fixed resistor to the junction,
+// sender from the junction to GND, ADC on the junction at A1 (GPIO3, ADC1; D0 strapping, D3 ADC2).
+// Output: one line per change, "<ms>\t<mV>\t<ohms>\t<pct>%", or "<ms>\t<mV>\topen".

@@ -0,0 +36,4 @@
+	const int32_t mv = averageMv();
+	const bool open = mv >= adcSaturationMv - openCircuitMarginMv;
+	const int32_t ohms = fixedOhms * mv / (supplyMv - mv);
+	const int32_t pct = open ? openPct : constrain((ohms - emptyOhms) * 100 / (fullOhms - emptyOhms), 0, 100);