Faulty connection somewhere on pcb

Other Hardware General Electronics
1

I have this humidity project that Im moving onto a pcb. But when i connect it to the power and after uploading the proper sketch (the one that worked fine on the breadboard), the lcd only displays empty boxes for each position, the ones that show up by default when there is no data to display.

Here is the project:

HumidityMonitorFaultyConnection.jpg
HumidityMonitorFaultyConnection.jpg1000×965 236 KB

So far Ive tested for continuity on all lcd wires including + and -.

Ive tested continuity for all wires going to the dht11 sensor. Here is the code:

#include <LiquidCrystal.h>
#include "DHT.h"
//for hdc1080
#include <Wire.h>
#include "ClosedCube_HDC1080.h"
//for lcd
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
//for dht22 grove pro
#define DHTPIN A1     // what pin we're connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)
DHT dht(DHTPIN, DHTTYPE);
//for hdc1080
ClosedCube_HDC1080 hdc1080;


void setup() {
  lcd.begin(16, 2);
  Serial.begin(9600); 
  Serial.println("DHTxx test!");
  dht.begin();
  hdc1080.begin(0x40);
}

void loop() {
 //printVolts();
 //if using hdc1080
 print1080();
 //if using grove dht11...
 printTempUndHum(); 
}
 
 void printVolts(){
  int sensorValue = analogRead(A0); //A0 V-Divider
  float voltage = sensorValue * (5.00 / 1023.00) * 1; //x1 if 3.7V or x2 if divider used (12KΩ)
  lcd.setCursor(0,0);
  lcd.print("V=");
  lcd.print(voltage); //print v to LCD
  lcd.print(" V");
  if (voltage < 3.50) //warn low V
  {
    //digitalWrite(led_pin, HIGH);
  }
}
//If using DHT11/Grove for T&H
void printTempUndHum(){
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  lcd.setCursor(0,0);
  lcd.print("T=");
  lcd.print(t);
  lcd.print("C");
  lcd.setCursor(7,0);
  lcd.print("H=");
  lcd.print(h);
  lcd.print("%");
}

void print1080(){
  float h = hdc1080.readHumidity();
  float t = hdc1080.readTemperature();
  lcd.setCursor(0,1);
  lcd.print("T=");
  lcd.print(t);
  lcd.print("C");
  lcd.setCursor(7,1);
  lcd.print("H=");
  lcd.print(h);
  lcd.print("%");
}

HumidityMonitorFaultyConnection.jpg
HumidityMonitorFaultyConnection.jpg1000×965 236 KB

2

If you want valid answers, you need to post more pictures of the wiring on the backside. Being it's a 3d fritzing, it can be difficult to follow .

That picture appears to show pins 12,11,10,9,5,3 going to the lcd whereas your code says 12,11,5,4,3,2.
Second is RS and EN look like pins 3,5, and the code shows 12,11.

3

You could try: Get a strong magnifier and light and closely examine every connection on the board - including the controller. Flex or poke at the solder joints or wiggle wires while doing this. Sometimes you can find cold solder joints this way. Remelt any that are suspect. Check also for solder bridges, it only takes a speck. Failing this, power up and repeat the above while watching for signs of life.

This all assumes you've already double checked the wiring is correct.

4

tinman13kup:
If you want valid answers, you need to post more pictures of the wiring on the backside. Being it's a 3d fritzing, it can be difficult to follow .

That picture appears to show pins 12,11,10,9,5,3 going to the lcd whereas your code says 12,11,5,4,3,2.
Second is RS and EN look like pins 3,5, and the code shows 12,11.

Hi tinman,

Yes I noticed that, Im using pins on the nano 12, 11, 10, 9, 4 and 2. So Ill fix that in code. Rs is 2 and En is 4.

So it should be: LiquidCrystal lcd(2,4,9,10,11,12);