Arduino sleep mode But keep LCD from Shutting off or resetting.

Projects Programming
1

Hello I was wondering something. I have a project using the Arduino pro mini, With the Nokia 5110 LCD and the Temperature/ Humidity Sensor the BME280. I got everything working and looks good. But i want to use it on Battery. So The key thing is to put the Arduino into sleep mode. I haven't tried sleep mode yet but i have saw others do it and I think i can do it But one problem remains The BME280 if powering it down and Also Powering the Nokia 5110 LCD down then reapplying Power to it the BME280 takes a while to Settle. So while that is happening I'm thinking that the Arduino will go back to sleep. From what I'm reading from Bosh website where the BME280 comes from the Datasheet says it takes anywhere from 1.8 to 3.6 Nano amps to run it. Now it could be more but that is Very low Power. I'm thinking of maybe Keeping the BME280 fully Power up. Also the Nokia LCD Fully power up from what I'm reading from a few websites the Nokia LCD It's all over the Place on what the Current is But it also looks like in the nano amps range So maybe Keep that running as well. But which leads me to the Reset pin when Trigger Low or High it resets the LCD. So not sure how to program it to make it keep the Last status of the BME280 displayed on the LCD.

This is my Sketch below. I need help to figure out how to keep it from Resetting. If anyone has any idea's please let me know? Thank you

#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include <Adafruit_BME280.h>
#include <Wire.h>

Adafruit_BME280 bme; // I2C
#define bme_ADDRESS 0x76
// SDA - A4 (D18)
// SCL - A5 (D19)

Adafruit_PCD8544 lcd = Adafruit_PCD8544(6, 5, 4, 3, 2);
// D7 - Serial clock out (CLK)
// D6 - Serial data out (DIN)
// D5 - Data/Command select (DC)
// D4 - LCD chip select (CE)
// D3 - LCD reset (RST)

float Temperature;
int Pressure, Humidity;

void setup() {
   pinMode(9, OUTPUT);
    pinMode(8, OUTPUT);
     pinMode(7, OUTPUT);
    digitalWrite(9, LOW);
    digitalWrite(8, LOW);
    digitalWrite(7, HIGH);
  lcd.begin();
  lcd.setContrast(30);
  lcd.clearDisplay();
  Wire.begin();
  bme.begin();
  delay(1000);  
 set_sleep_mode (SLEEP_MODE_PWR_DOWN);  
  sleep_enable();
  sleep_cpu (); 
}          
void loop(void) { 
   lcd.clearDisplay();
  lcd.setTextSize(1);

  lcd.setCursor(0,0);
  lcd.print(bme.readPressure()/1.333);lcd.print(" MMHG");
  lcd.setCursor(0,10);
    lcd.setTextSize(2);
  lcd.print(bme.readTemperature(),1);lcd.print("c");
 
  lcd.setCursor(0,30);
  lcd.print(bme.readHumidity());lcd.print("%");
  set_text(60,40,"",BLACK);

  delay(1000);
}
void set_text(int x,int y,String text,int color){
  lcd.setTextColor(color);
  lcd.setCursor(x,y);
  lcd.println(text);
  lcd.display();
}

Looking at Nickgammon site about sleep i did mange to get it sleeping But I'm a little confused on how to wake it up after 2 minutes and Refresh stuff what is displayed with the newest information.

2

I think i found what I'm looking for. I found this Github about sleep modes and timers Here. Going to give it a try as soon as i learn more about it. It seems to do what i need it to do. Sleep for 5 minutes then wake up take readings and then go back to sleep.

But I'm still working if Keeping the LCD power up the whole time and keeping the Bosch BME280 Power up would drain the battery faster. Sense both are at Micro amps range??

3

Hello i know this is a old post But i wanted to revisit it and see if i can make it work. So i have tried the library and sketch from the link i posted. It does work. The arduino does go to sleep. However it's not working to well. What i mean is when on I tell it to turn on Led13 for 8 second then turn if off for 8 seconds. When all powered up it takes 10.84 ma. But in sleep mode it takes 4.84 ma. However after some time the sleep mode goes down to 2.73 ma I'm not sure what is going on. Not even sure how to get it the power down more when sleep. Can someone please help me Sketch is attached below. also here again is the link for the libray here.

#include <Sleep_n0m1.h>

Sleep sleep;
unsigned long sleepTime; //how long you want the arduino to sleep



void setup()
{
   
   Serial.begin(9600);
   sleepTime = 8000; //set sleep time in ms, max sleep time is 49.7 days
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop()
{
  
  delay(100); ////delays are just for serial print, without serial they can be removed
  Serial.println("execute your code here");
  
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(8000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  
  Serial.print("sleeping for ");
  Serial.println(sleepTime); 
  delay(100); //delay to allow serial to fully print before sleep
    
  sleep.pwrDownMode(); //set sleep mode
  sleep.sleepDelay(sleepTime); //sleep for: sleepTime
 
 
  
}