testing baumer sensors

AltSensorTesting/AltSensorTesting.ino

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+#include <Arduino.h>
+#include <util/atomic.h>
+
+// ── ADC Interrupt-driven single-channel read (A0) ────────────
+volatile uint16_t adc_result = 0;
+volatile bool     adc_ready  = false;
+
+void setupADC() {
+  // Reference = AVCC (5 V)
+  ADMUX = (1 << REFS0);
+
+  // Channel = A0 (MUX[3:0] = 0000)
+  ADMUX &= 0xF0;
+
+  // Prescaler = 16  → 16 MHz / 16 = 1 MHz ADC clock
+  // Each conversion ≈ 13 ADC clocks → ~76.9 kHz sample rate
+  ADCSRA = (1 << ADEN)  | (1 << ADIE)
+         | (1 << ADPS2);               // ADPS = 100 → /16
+
+  // Start first conversion
+  ADCSRA |= (1 << ADSC);
+}
+
+// ── OOR digital input ────────────────────────────────────────
+#define OOR_PIN 2          // digital pin 2 — HIGH = out of range
+
+volatile bool OOR;
+
+ISR(ADC_vect) {
+  uint16_t sample = ADC;
+  // Discard if OOR pin (PD2) is HIGH
+  OOR = (digitalRead(OOR_PIN));
+  if (!OOR) {
+    adc_result = sample;
+    adc_ready  = true;
+  }
+  ADCSRA |= (1 << ADSC); // kick off next conversion immediately
+}
+
+// ── ADC → mm linear mapping ─────────────────────────────────
+// ADC 185 → 16 mm,  ADC 900 → 26 mm
+// #define adcToMM(adc) (16.0f + (float)((adc) - 185) * (10.0f / 715.0f))
+#define adcToMM(adc) (0.0f + (float)((adc) - 0) * (10.0f / 1024.0f))
+
+// ── Boundary tracking (in-range only) ────────────────────────
+#define TRACK_N 10
+uint16_t lowestVals[TRACK_N];
+uint16_t highestVals[TRACK_N];
+uint8_t  lowestCount  = 0;
+uint8_t  highestCount = 0;
+
+// Insert val into a sorted-ascending array of up to TRACK_N entries
+// keeping only the N smallest values seen so far.
+static void trackLowest(uint16_t val) {
+  if (lowestCount < TRACK_N) {
+    // Array not full — insert in sorted position
+    uint8_t i = lowestCount;
+    while (i > 0 && lowestVals[i - 1] > val) {
+      lowestVals[i] = lowestVals[i - 1];
+      i--;
+    }
+    lowestVals[i] = val;
+    lowestCount++;
+  } else if (val < lowestVals[TRACK_N - 1]) {
+    // Replace the current largest of the "lowest" set
+    uint8_t i = TRACK_N - 1;
+    while (i > 0 && lowestVals[i - 1] > val) {
+      lowestVals[i] = lowestVals[i - 1];
+      i--;
+    }
+    lowestVals[i] = val;
+  }
+}
+
+// Insert val into a sorted-descending array of up to TRACK_N entries
+// keeping only the N largest values seen so far.
+static void trackHighest(uint16_t val) {
+  if (highestCount < TRACK_N) {
+    uint8_t i = highestCount;
+    while (i > 0 && highestVals[i - 1] < val) {
+      highestVals[i] = highestVals[i - 1];
+      i--;
+    }
+    highestVals[i] = val;
+    highestCount++;
+  } else if (val > highestVals[TRACK_N - 1]) {
+    uint8_t i = TRACK_N - 1;
+    while (i > 0 && highestVals[i - 1] < val) {
+      highestVals[i] = highestVals[i - 1];
+      i--;
+    }
+    highestVals[i] = val;
+  }
+}
+
+static void resetTracking() {
+  lowestCount  = 0;
+  highestCount = 0;
+}
+
+static void printBoundaries() {
+  Serial.println(F("--- 10 Lowest In-Range ADC Values ---"));
+  for (uint8_t i = 0; i < lowestCount; i++) {
+    Serial.println(lowestVals[i]);
+  }
+  Serial.println(F("--- 10 Highest In-Range ADC Values ---"));
+  for (uint8_t i = 0; i < highestCount; i++) {
+    Serial.println(highestVals[i]);
+  }
+}
+
+// ── State ────────────────────────────────────────────────────
+bool sampling = false;
+
+// ═════════════════════════════════════════════════════════════
+void setup() {
+  Serial.begin(2000000);
+  pinMode(OOR_PIN, INPUT);
+  setupADC();
+  Serial.println(F("Send '1' to start sampling, '0' to stop and print bounds."));
+}
+
+void loop() {
+  // ── Serial command handling ──────────────────────────────
+  if (Serial.available() > 0) {
+    String cmd = Serial.readStringUntil('\n');
+    cmd.trim();
+
+    if (cmd.charAt(0) == '1') {
+      sampling = true;
+      resetTracking();
+      Serial.println(F("Sampling started."));
+    } else if (cmd.charAt(0) == '0') {
+      sampling = false;
+      Serial.println(F("Sampling stopped."));
+      printBoundaries();
+    }
+  }
+
+  // ── Main sample path ────────────────────────────────────
+  if (!sampling) return;
+
+  // Grab the latest ADC value atomically
+  uint16_t val;
+  bool ready;
+  bool newOOR;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    ready = adc_ready;
+    val   = adc_result;
+    adc_ready = false;
+    newOOR = OOR;
+  }
+
+  if (!ready) return;  // nothing new — come back next iteration
+
+  // All values here are in-range (OOR filtered in ISR)
+  trackLowest(val);
+  trackHighest(val);
+
+  float mm = adcToMM(val);
+  Serial.print(val);
+  Serial.print(", ");
+  Serial.print(mm, 2);
+  Serial.print(" mm, ");
+  Serial.println(newOOR ? "out of range" : "in range");
+}