October 16, 2021 by Mirko Pavleski
Weather forecaster, which displays the weather forecast on the screen in the form of descriptive text.
| 1 | Arduino Nano R3 | ||
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| 1 | VFD Display with 20x2 characters | ||
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| 1 | MyOctopus i2c Barometric Air Pressure Sensor BMP280 | ||
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| 1 | Maxim Integrated DS3231M - ±5ppm, I2C Real-Time Clock | ||
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| 1 | Arduino IDE | ||
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| 1 | Soldering iron (generic) | ||
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| 1 | Solder Wire, Lead Free | ||
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In one of my previous videos, I described how to make a cheap Advanced Barometer, used by sailors, yachtsmen, etc. It is a great weather forecasting device but still requires some knowledge in the field of meteorology.
This time I will show you how to make a Zambreti weather forecaster, which displays the weather forecast on the screen in the form of descriptive text. It contains a total of 26 reports that describe in detail the weather forecast.
The original Zambretti Forecaster was developed in 1915 by precision instrument makers Negretti and Zambra. It was a hand-held disc calculator, that provided on-demand short-term forecasts of up to 12 hours. It consists of 3 plastic discs of descending radius, arranged concentrically and secured together by means of a rivet. The large outside disc A has a short scale calibrated in wind direction, the middle disc B, has an index to be aligned appropriately with the wind direction scale on A, and itself carries a scale calibrated in units of barometric pressure (inches of mercury or millibars). The inner disc C has an index settable to the atmospheric pressure on B and three windows which allow the selection of a reading based upon of the rising or falling of the barometer in Winter or Summer. Through the appropriate window, an alphabetic letter is visible ( printed on disc A) and this letter is the key to the forecast which can be read off on the obverse side of the instrument. It is reported that the forecasts are most accurate when generated at 9.00 am local time. The calculator uses the mean sea level pressure (MSLP) and pressure trend (steady, rising or falling) as the primary input. The season (Summer or Winter) and the wind play a minor role in determining the forecast.
This device was an electronic version of this calculator that automatically generates reports on the display. It is very simple to make and consists of several components:
- Arduino Nano microcontroller
- 20x2 VFD display from old POS Terminal
- DS3231 Real time clock module
- and BME or BMP280 sensor board
Also in one of my previous videos I showed you how to control an unknown VFD display via a tx-rx connection with Arduino (https://www.youtube.com/watch?v=FZi8vyAs57w&t=83s).
DS3231 Realtime clock module serves only to determine the season (winter or summer). Of course with very small changes in the code this device can be made with a 16x2 LCD display which is much easier to control. As a basis, I used Fandonov's code for an e-paper weather station (https://github.com/fandonov/weatherstation/)
Immediately after switching on, a short time report and the current value of the Relative Atmospheric Pressure appear on the screen. This weather report is based on momentary pressure and is not realistic. The first realistic weather report appears after one hundred minutes and is updated every 10 minutes. The current Relative Atmospheric Pressure is displayed in the lower right corner and is updated every minute. There are a total of 26 weather forecasts that describe in detail what the weather will be like in the next 12 hours:
1. Settled Fine
2. Fine Weather
3. Becoming Fine
4. Fine Becoming Less Settled
5. Fine, Possibly showers
6. Fairly Fine, Improving
7. Fairly Fine, Possibly showers, early
8. Fairly Fine Showery Later
9. Showery Early, Improving
10. Changeable Mending
11. Fairly Fine, Showers likely
12. Rather Unsettled Clearing Later
13. Unsettled, Probably Improving
14. Showery Bright Intervals
15. Showery Becoming more unsettled
16. Changeable some rain
17. Unsettled, short fine Intervals
18. Unsettled, Rain later
19. Unsettled, rain at times
20. Very Unsettled, Finer at times
21. Rain at times, worse later.
22. Rain at times, becoming very unsettled
23. Rain at Frequent Intervals
24. Very Unsettled, Rain
25. Stormy, possibly improving
26. Stormy, much rain
I should also mention that the code should include the altitude of the place where the device is located, in the row:
int altitude = 723; // Here you should put the REAL altitude
Also in the upper left corner, there is a sign that shows us the trend of atmospheric pressure (raising, steady, or falling).
Finally, the device is built into a suitable box made of PVC board coated with self-adhesive colored wallpaper.
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BMP280.h>
#include "RTClib.h"
#define SEALEVELPRESSURE_HPA (1013.25)
RTC_DS3231 rtc; // initialise the RTC DS3231
Adafruit_BMP280 BMP; // initialise the BMP280 sensor
unsigned long delayTime; // refresh rate for the readings
int t_hour = 0;
int t_minute = 0;
//int t_second =0;
int pressureArray[10] = {0}; // here we store the pressure readings
byte counter = 0;
byte delta_time = 0;
int Z = 0;
char tStr[21];
char pStr[22];
char hStr[20];
char pseaStr[26];
char timeStr[6];
char dateStr[12];
char zambretti[10] = "N/A";
char pressureHistory[57];
char pressureHistory2[57];
int temperature;
int humidity;
int pressure;
int altitude = 725; // Here you should put the REAL altitude of the iGnome
void setup() {
bool status;
Serial.begin(4800); // default settings
Serial.print(" Zambretti Weather forecaster ");
delay(5000);
if (! rtc.begin()) {
Serial.write("Couldn't find RTC");
while (1);
}
if (rtc.lostPower()) {
Serial.write("RTC lost power, lets set the time!");
// following line sets the RTC to the date & time this sketch was compiled
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
status = BMP.begin(0x76);
if (!status) {
while (1);
}
delayTime = 20000;
}
void loop() {
temperature = (int)BMP.readTemperature();
// humidity = (int)BMP.readHumidity();
pressure = (int)(BMP.readPressure() / 100.0F);
// Let's see the reading that will determine the forecast
// Serial.print("Measured altitude ");
// Serial.write((int)BMP.readAltitude(SEALEVELPRESSURE_HPA));
int seapressure = station2sealevel(pressure, altitude, temperature);
DateTime now = rtc.now();
int t_hour2 = now.hour();
int t_minute2 = now.minute();
// int t_second2 = now.second();
if (t_hour2 != t_hour or t_minute2 != t_minute) {
delta_time++;
if (delta_time > 10) { // every minute we increment delta_time, then every 10 minutes
delta_time = 0; // we store the value in the array
if (counter == 10) // if we read 10 values and filled up the array, we shift the array content
{
for (int i = 0; i < 9; i++) { // we shift the array one position to the left
pressureArray[i] = pressureArray[i + 1];
}
pressureArray[counter - 1] = seapressure;
}
else { // this code fills up the pressure array value by value until is filled up
pressureArray[counter] = seapressure;
counter++;
}
}
Z = calc_zambretti((pressureArray[9] + pressureArray[8] + pressureArray[7]) / 3, (pressureArray[0] + pressureArray[1] + pressureArray[2]) / 3, now.month());
// From here is just for debug purposes on the serial monitor
/*
sprintf(zambretti, "Z=%d", Z);
sprintf(tStr, "%d C", temperature);
sprintf(hStr, "%d %%", humidity);
sprintf(pStr, "%d hPa", pressure);
sprintf(pseaStr, "%d hPa", seapressure);
sprintf(dateStr, "%02d.%02d.%d", now.day(), now.month(), now.year());
sprintf(timeStr, "%02d:%02d", now.hour(), now.minute());
sprintf(pressureHistory, "%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,", pressureArray[0], pressureArray[1], pressureArray[2],
pressureArray[3], pressureArray[4], pressureArray[5], pressureArray[6], pressureArray[7], pressureArray[8], pressureArray[9]);
Serial.write(zambretti);
Serial.write(tStr);
Serial.write(hStr);
Serial.write(pStr);
Serial.write(pseaStr);
Serial.write(dateStr);
Serial.write(timeStr);
Serial.write(pressureHistory);
Serial.write(pressureHistory2);
*/
// END of testing purposes
if (pressureArray[9] > 0 and pressureArray[0] > 0) {
if (pressureArray[9] + pressureArray[8] + pressureArray[7] - pressureArray[0] - pressureArray[1] - pressureArray[2] >= 3) {
//RAISING
Serial.print("[>] ");
if (Z<2){
Serial.write("Settled Fine ");
}
else if (Z>1 and Z<=2){
Serial.write("Fine Weather ");
}
else if (Z>2 and Z<=3){
Serial.write("Becoming Fine ");
}
else if (Z>3 and Z<=4){
Serial.write("Fine Becoming Less Settled ");
}
else if (Z>4 and Z<=5){
Serial.write("Fine Possibly Showers ");
}
else if (Z>5 and Z<=6){
Serial.write("Fairly Fine Improving ");
}
else if (Z>6 and Z<=7){
Serial.write("Fairly Fine Pos.Showers, early ");
}
else if (Z>7 and Z<=8){
Serial.write("Fairly Fine Showery Later ");
}
else if (Z>8 and Z<=9){
Serial.write("Showery Early Improving ");
}
else if (Z>9 and Z<=10){
Serial.write("Changeable Mending ");
}
else if (Z>10 and Z<=11){
Serial.write("Fairly Fine Showers likely ");
}
else if (Z>11 and Z<=12){
Serial.write("Rather UnsettledClearing Later ");
}
else if (Z>12 and Z<=13){
Serial.write("Unsettled Prob. Improving ");
}
else if (Z>13 and Z<=14){
Serial.write("Showery Bright Intervals ");
}
else if (Z>14 and Z<=15){
Serial.write("Showery BecomingMore Unsettled ");
}
else if (Z>15 and Z<=16){
Serial.write("Changeable Some Rain ");
}
else if (Z>16 and Z<=17){
Serial.write("Unsettled Short Fine Intervals ");
}
else if (Z>17 and Z<=18){
Serial.write("Unsettled Rain later ");
}
else if (Z>18 and Z<=19){
Serial.write("Unsettled Rain at time ");
}
else if (Z>19 and Z<=20){
Serial.write("Very Unsettled Finer at time ");
}
else if (Z>20 and Z<=21){
Serial.write("Rain at times Worse later ");
}
else if (Z>21 and Z<=22){
Serial.write("Rain at times Bec. Very Uns. ");
}
else if (Z>22 and Z<=23){
Serial.write("Rain at Frequent Intervals ");
}
else if (Z>23 and Z<=24){
Serial.write("Very Unsettled Rain ");
}
else if (Z>24 and Z<=25){
Serial.write("Stormy possibly Improving ");
}
else if (Z>25 and Z<=26){
Serial.write("Stormy Much Rain ");
}
}
else if (pressureArray[0]+pressureArray[1]+pressureArray[2]-pressureArray[9]-pressureArray[8]-pressureArray[7]>=3){
//FALLING
Serial.print("[<] ");
if (Z<2){
Serial.write("Settled Fine ");
}
else if (Z>1 and Z<=2){
Serial.write("Fine Weather ");
}
else if (Z>2 and Z<=3){
Serial.write("Becoming Fine ");
}
else if (Z>3 and Z<=4){
Serial.write("Fine Becoming Less Settled ");
}
else if (Z>4 and Z<=5){
Serial.write("Fine Possibly Showers ");
}
else if (Z>5 and Z<=6){
Serial.write("Fairly Fine Improving ");
}
else if (Z>6 and Z<=7){
Serial.write("Fairly Fine Pos.Showers, early ");
}
else if (Z>7 and Z<=8){
Serial.write("Fairly Fine Showery Later ");
}
else if (Z>8 and Z<=9){
Serial.write("Showery Early Improving ");
}
else if (Z>9 and Z<=10){
Serial.write("Changeable Mending ");
}
else if (Z>10 and Z<=11){
Serial.write("Fairly Fine Showers likely ");
}
else if (Z>11 and Z<=12){
Serial.write("Rather UnsettledClearing Later ");
}
else if (Z>12 and Z<=13){
Serial.write("Unsettled Prob. Improving ");
}
else if (Z>13 and Z<=14){
Serial.write("Showery Bright Intervals ");
}
else if (Z>14 and Z<=15){
Serial.write("Showery BecomingMore Unsettled ");
}
else if (Z>15 and Z<=16){
Serial.write("Changeable Some Rain ");
}
else if (Z>16 and Z<=17){
Serial.write("Unsettled Short Fine Intervals ");
}
else if (Z>17 and Z<=18){
Serial.write("Unsettled Rain later ");
}
else if (Z>18 and Z<=19){
Serial.write("Unsettled Rain at time ");
}
else if (Z>19 and Z<=20){
Serial.write("Very Unsettled Finer at time ");
}
else if (Z>20 and Z<=21){
Serial.write("Rain at times Worse later ");
}
else if (Z>21 and Z<=22){
Serial.write("Rain at times Bec. Very Uns. ");
}
else if (Z>22 and Z<=23){
Serial.write("Rain at Frequent Intervals ");
}
else if (Z>23 and Z<=24){
Serial.write("Very Unsettled Rain ");
}
else if (Z>24 and Z<=25){
Serial.write("Stormy possibly Improving ");
}
else if (Z>25 and Z<=26){
Serial.write("Stormy Much Rain ");
}
}
else{
//STEADY
Serial.print("[=] ");
if (Z<2){
Serial.write("Settled Fine ");
}
else if (Z>1 and Z<=2){
Serial.write("Fine Weather ");
}
else if (Z>2 and Z<=3){
Serial.write("Becoming Fine ");
}
else if (Z>3 and Z<=4){
Serial.write("Fine Becoming Less Settled ");
}
else if (Z>4 and Z<=5){
Serial.write("Fine Possibly Showers ");
}
else if (Z>5 and Z<=6){
Serial.write("Fairly Fine Improving ");
}
else if (Z>6 and Z<=7){
Serial.write("Fairly Fine Pos.Showers, early ");
}
else if (Z>7 and Z<=8){
Serial.write("Fairly Fine Showery Later ");
}
else if (Z>8 and Z<=9){
Serial.write("Showery Early Improving ");
}
else if (Z>9 and Z<=10){
Serial.write("Changeable Mending ");
}
else if (Z>10 and Z<=11){
Serial.write("Fairly Fine Showers likely ");
}
else if (Z>11 and Z<=12){
Serial.write("Rather UnsettledClearing Later ");
}
else if (Z>12 and Z<=13){
Serial.write("Unsettled Prob. Improving ");
}
else if (Z>13 and Z<=14){
Serial.write("Showery Bright Intervals ");
}
else if (Z>14 and Z<=15){
Serial.write("Showery BecomingMore Unsettled ");
}
else if (Z>15 and Z<=16){
Serial.write("Changeable Some Rain ");
}
else if (Z>16 and Z<=17){
Serial.write("Unsettled Short Fine Intervals ");
}
else if (Z>17 and Z<=18){
Serial.write("Unsettled Rain later ");
}
else if (Z>18 and Z<=19){
Serial.write("Unsettled Rain at time ");
}
else if (Z>19 and Z<=20){
Serial.write("Very Unsettled Finer at time ");
}
else if (Z>20 and Z<=21){
Serial.write("Rain at times Worse later ");
}
else if (Z>21 and Z<=22){
Serial.write("Rain at times Bec. Very Uns. ");
}
else if (Z>22 and Z<=23){
Serial.write("Rain at Frequent Intervals ");
}
else if (Z>23 and Z<=24){
Serial.write("Very Unsettled Rain ");
}
else if (Z>24 and Z<=25){
Serial.write("Stormy possibly Improving ");
}
else if (Z>25 and Z<=26){
Serial.write("Stormy Much Rain ");
}
}
}
else {
if (seapressure < 1005) {
Serial.write(" Rainy ");
}
else if (seapressure >= 1005 and seapressure <= 1015) {
Serial.write(" Cloudy ");
}
else if (seapressure > 1015 and seapressure < 1025) {
//Serial.write("[=] ");
Serial.write(" Sunny Cloudy ");
}
else {
Serial.write(" Sunny ");
}
}
if (seapressure <=999)
{
Serial.print("*");
Serial.print(seapressure);
delay(2000);
}
else {
Serial.print(seapressure);
delay(2000);
}
t_hour = t_hour2;
t_minute = t_minute2;
// t_second = t_second2;
}
}
int calc_zambretti(int curr_pressure, int prev_pressure, int mon) {
if (curr_pressure < prev_pressure) {
//FALLING
if (mon >= 4 and mon <= 9)
//summer
{
if (curr_pressure >= 1030)
return 2;
else if (curr_pressure >= 1020 and curr_pressure < 1030)
return 8;
else if (curr_pressure >= 1010 and curr_pressure < 1020)
return 18;
else if (curr_pressure >= 1000 and curr_pressure < 1010)
return 21;
else if (curr_pressure >= 990 and curr_pressure < 1000)
return 24;
else if (curr_pressure >= 980 and curr_pressure < 990)
return 24;
else if (curr_pressure >= 970 and curr_pressure < 980)
return 26;
else if (curr_pressure < 970)
return 26;
}
else {
//winter
if (curr_pressure >= 1030)
return 2;
else if (curr_pressure >= 1020 and curr_pressure < 1030)
return 8;
else if (curr_pressure >= 1010 and curr_pressure < 1020)
return 15;
else if (curr_pressure >= 1000 and curr_pressure < 1010)
return 21;
else if (curr_pressure >= 990 and curr_pressure < 1000)
return 22;
else if (curr_pressure >= 980 and curr_pressure < 990)
return 24;
else if (curr_pressure >= 970 and curr_pressure < 980)
return 26;
else if (curr_pressure < 970)
return 26;
}
}
else if (curr_pressure > prev_pressure) {
//RAISING
if (mon >= 4 and mon <= 9) {
//summer
if (curr_pressure >= 1030)
return 1;
else if (curr_pressure >= 1020 and curr_pressure < 1030)
return 2;
else if (curr_pressure >= 1010 and curr_pressure < 1020)
return 3;
else if (curr_pressure >= 1000 and curr_pressure < 1010)
return 7;
else if (curr_pressure >= 990 and curr_pressure < 1000)
return 9;
else if (curr_pressure >= 980 and curr_pressure < 990)
return 12;
else if (curr_pressure >= 970 and curr_pressure < 980)
return 17;
else if (curr_pressure < 970)
return 17;
}
else
//winter
{
if (curr_pressure >= 1030)
return 1;
else if (curr_pressure >= 1020 and curr_pressure < 1030)
return 2;
else if (curr_pressure >= 1010 and curr_pressure < 1020)
return 6;
else if (curr_pressure >= 1000 and curr_pressure < 1010)
return 7;
else if (curr_pressure >= 990 and curr_pressure < 1000)
return 10;
else if (curr_pressure >= 980 and curr_pressure < 990)
return 13;
else if (curr_pressure >= 970 and curr_pressure < 980)
return 17;
else if (curr_pressure < 970)
return 17;
}
}
else {
if (curr_pressure >= 1030)
return 1;
else if (curr_pressure >= 1020 and curr_pressure < 1030)
return 2;
else if (curr_pressure >= 1010 and curr_pressure < 1020)
return 11;
else if (curr_pressure >= 1000 and curr_pressure < 1010)
return 14;
else if (curr_pressure >= 990 and curr_pressure < 1000)
return 19;
else if (curr_pressure >= 980 and curr_pressure < 990)
return 23;
else if (curr_pressure >= 970 and curr_pressure < 980)
return 24;
else if (curr_pressure < 970)
return 26;
}
}
int station2sealevel(int p, int height, int t) { // from pressure at our height to sea level
return (double) p * pow(1 - 0.0065 * (double)height / (t + 0.0065 * (double)height + 273.15), -5.275);
}Electronics , Arduino , Physics
