From 0971859f463761c2845716ee08441184013fc429 Mon Sep 17 00:00:00 2001
From: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Date: Wed, 12 Jul 2023 22:32:53 -0400
Subject: [PATCH] Add calibration code

---
 touch-sensor/main.c | 47 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/touch-sensor/main.c b/touch-sensor/main.c
index 4a141ef..89f2e60 100644
--- a/touch-sensor/main.c
+++ b/touch-sensor/main.c
@@ -14,6 +14,18 @@ uint32_t read_capacitance(dio_t *dio) {
     return i;
 }
 
+uint32_t calibrate(dio_t *dio) {
+    uint32_t max = 0;
+
+    for (uint8_t i = 0; i < 100; i++) {
+        uint8_t cap = read_capacitance(dio);
+        max = cap > max ? cap : max;
+        _delay_ms(10);
+    }
+
+    return max;
+}
+
 int main(void) {
     dio_t sensor = (dio_t){ .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 0 };
     display_t display = {
@@ -28,10 +40,6 @@ int main(void) {
     display_enable(&display);
     display_clear(&display);
 
-    display_set_location(&display, 0, 0);
-    display_write_message(&display, "Ready");
-
-
     // calibration
     //
     // 100 times:
@@ -51,12 +59,35 @@ int main(void) {
     MCUCR |= _BV(PUD);
 
 
+    uint8_t calibration_countdown = 0;
+    uint32_t calibration = 0;
+    bool touch = false;
     while (1) {
+        if (calibration_countdown == 0 && !touch) {
+            calibration = calibrate(&sensor);
+            calibration_countdown = 100;
+
+            char msg[20];
+            snprintf(msg, 20, "calib: %6ld", calibration);
+            display_set_location(&display, 0, 0);
+            display_write_message(&display, msg);
+        }
+
         uint32_t cap = read_capacitance(&sensor);
-        char msg[20];
-        snprintf(msg, 20, "cap: %5ld", cap);
-        display_set_location(&display, 1, 0);
-        display_write_message(&display, msg);
+
+        if (cap > calibration) {
+            display_set_location(&display, 1, 0);
+            display_write_message(&display, "touch!");
+            touch = true;
+        } else if (touch) {
+            display_set_location(&display, 1, 0);
+            display_write_message(&display, "      ");
+            touch = false;
+        }
+
+        if (calibration_countdown > 0) {
+            calibration_countdown--;
+        }
         _delay_ms(100);
     }