Repurposing an Old Voltmeter

1// Using a DHT 22 on pin 7 and a 0.96 inch OLED display
2
3#include  <DHT.h>
4#include <U8g2lib.h>
5#include "RTClib.h"
6
7U8G2_SH1106_128X64_NONAME_F_HW_I2C  u8g2(U8G2_R0, U8X8_PIN_NONE);
8
9RTC_DS1307 RTC;
10
11//Constants
12#define  DHTPIN 7              // PIN for DHT 22
13#define DHTTYPE DHT22         //DHT 22  (AM2302)
14DHT dht(DHTPIN, DHTTYPE);
15
16//Variabler
17int count;
18int chk;                      //counter for cursor
19float hum;                    //Stores  humidity value
20float temp;                   //Stores temperature value
21
22void  setup(void)
23{
24  u8g2.begin();
25  RTC.begin();
26
27  if (! RTC.isrunning())  {
28    // following line sets the RTC to the date & time this sketch was compiled
29    RTC.adjust(DateTime(__DATE__, __TIME__));
30  }
31}
32
33void TempHum()  {                                            // write temp and hum on OLED
34  u8g2.clearBuffer();
35  u8g2.setContrast(255);
36  u8g2.drawRFrame(0 - chk, 0, 128, 64, 7);
37  u8g2.setFont(  u8g2_font_helvB24_tf);                      // Font
38  u8g2.setCursor( 17 - chk,  28);                            // Kursor
39  u8g2.print(temp, 1);                                      //  Write temp
40  u8g2.drawCircle(80 - chk, 5, 2, U8G2_DRAW_ALL);           // Make  a °
41  u8g2.print(" C");                                        // Celsius
42  u8g2.setCursor( 17 - chk, 60);                            // Cursor
43  u8g2.print(hum,  1);                                        // write hum
44  u8g2.print(" %");                                         // Write %
45  u8g2.sendBuffer();
46}
47
48void  dateTime() {                                         //Write date and time on OLED
49  DateTime now = RTC.now();
50  u8g2.clearBuffer();
51  u8g2.drawRFrame(0 - chk,  0, 128, 64, 7);
52  u8g2.setFont( u8g2_font_timB24_tn);                     //  Font
53  u8g2.setCursor(5 - chk, 27);                            // Kursor
54  if (now.hour() < 10)
55    u8g2.print("0");
56  u8g2.print(now.hour(), DEC);                            // Write hour
57  u8g2.print(":");
58  if (now.minute()  < 10)
59    u8g2.print("0");
60  u8g2.print(now.minute(), DEC);                           //  Write hour
61  u8g2.print(":");
62  if (now.second() < 10)
63    u8g2.print("0");
64  u8g2.print(now.second(), DEC);
65  u8g2.setCursor( 7 - chk, 60);                            //  Cursor
66  u8g2.setFont( u8g2_font_timB18_tn);                      // Font
67  u8g2.print(now.year(), DEC);                             // Write year
68  u8g2.print("-");
69  if (now.month() < 10)
70    u8g2.print("0");
71  u8g2.print(now.month(), DEC);                            // Write month
72  u8g2.print("-");
73  if (now.day()  < 10)
74    u8g2.print("0");
75  u8g2.print(now.day(), DEC);                              //  write day
76  u8g2.sendBuffer();
77}
78
79void loop(void)
80{
81  chk = -128;
82  do {                                    // let Temp and hum slide in
83    TempHum();
84    chk = chk + 1;
85    delay(1);
86  } while (chk < 1);
87
88  delay(3000);
89
90  hum = dht.readHumidity();               // read hum
91  temp = dht.readTemperature();           // read temp
92
93  chk = 0;
94  do {                                    //  let Temp and hum slide out
95    TempHum();
96    delay(1);
97    chk = chk +  1;
98  } while (chk < 129);
99
100  chk = -128;
101  do {                                    //  let time and date slide in
102    dateTime();
103    chk = chk + 1;
104    delay(1);
105  } while (chk < 0);
106
107  count = 0;
108  do {                          // split  the delay of 3000 into six 500 delays to have a smoother sec display
109    dateTime();
110    delay(10);
111    count = count + 1;
112  } while (count < 30);
113
114  chk  = 0;
115  do {                                   // let Temp and hum slide out
116    dateTime();
117    delay(1);
118    chk = chk + 1;
119  } while (chk < 129);
120  chk = 0;
121}
122
123