DIY Shortwave Propagation Monitor - Measure Ionosphere Conditions

1//  by mircemk  April, 2026
2
3#include <Wire.h>
4#include <Adafruit_GFX.h>
5#include <Adafruit_SSD1306.h>
6
7#define SCREEN_WIDTH 128
8#define SCREEN_HEIGHT 64
9Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
10
11// ---- UI (поголем BOX долу) ----
12const int BAR_Y = 2;
13const int BAR_H = 12;
14const int BAR_X = 2;
15const int BAR_W = 124;
16
17const int BOX_X = 6;     // помал margin
18const int BOX_Y = 20;    // спуштено нагоре малку
19const int BOX_W = 116;   // пошироко
20const int BOX_H = 44;    // повисоко (скоро до дното)
21const int BOX_R = 8;
22
23// ---- Analog ----
24const int ANALOG_PIN = A0;
25
26// ======= РАНГ (ADC) =======
27int IN_MIN = 60;
28int IN_MAX = 1000;
29
30static inline int clampInt(int v, int lo, int hi) {
31  if (v < lo) return lo;
32  if (v > hi) return hi;
33  return v;
34}
35
36static inline int mapLongToInt(long x, long in_min, long in_max, long out_min, long out_max) {
37  if (in_max == in_min) return (int)out_min;
38  return (int)((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min);
39}
40
41void drawCenteredTextInBox(const char* txt, int textSize) {
42  display.setTextSize(textSize);
43
44  int16_t x1, y1;
45  uint16_t w, h;
46  display.getTextBounds(txt, 0, 0, &x1, &y1, &w, &h);
47
48  int tx = BOX_X + (BOX_W - (int)w) / 2;
49  int ty = BOX_Y + (BOX_H - (int)h) / 2;
50
51  display.setCursor(tx, ty);
52  display.print(txt);
53}
54
55void setup() {
56  analogReference(DEFAULT);
57  Wire.begin();
58
59  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
60    while (1) {}
61  }
62  display.clearDisplay();
63  display.setTextColor(SSD1306_WHITE);
64  display.display();
65}
66
67void loop() {
68  int raw = analogRead(ANALOG_PIN);
69
70  int a = IN_MIN, b = IN_MAX;
71  if (a > b) { int t = a; a = b; b = t; }
72
73  int rawWin = clampInt(raw, a, b);
74
75  int rel1000 = mapLongToInt(rawWin, a, b, 0, 1000);
76  int barFill = mapLongToInt(rawWin, a, b, 0, BAR_W);
77
78  display.clearDisplay();
79
80  // BAR
81  display.drawRect(BAR_X, BAR_Y, BAR_W, BAR_H, SSD1306_WHITE);
82  int innerW = barFill - 2;
83  if (innerW < 0) innerW = 0;
84  if (innerW > BAR_W - 2) innerW = BAR_W - 2;
85  display.fillRect(BAR_X + 1, BAR_Y + 1, innerW, BAR_H - 2, SSD1306_WHITE);
86
87  // BOX
88  display.drawRoundRect(BOX_X, BOX_Y, BOX_W, BOX_H, BOX_R, SSD1306_WHITE);
89
90  // број (auto size: 0-999 големо, 1000 помало)
91  char buf[6];
92  snprintf(buf, sizeof(buf), "%d", rel1000);
93
94  int size = (rel1000 >= 1000) ? 3 : 4;  // 1000 да собере
95  drawCenteredTextInBox(buf, size);
96
97  display.display();
98  delay(1000);
99}