LCD + DHT22 Help

Projects General Guidance
1

Hi there-

I'm new to arduino, and programming/electronics in general. I received an arduino and a seeedstudio starter kit along with some various sensors as a gift a couple months ago, and I've been tinkering with it since.

Anyways, I've been trying to make a temperature and humidity gauge using the DHT22 sensor and 16 x 2 LCD display. Here is my code:

#include <SerialLCD.h>
#include <SoftwareSerial.h>
#include "DHT.h"
#define DHTPIN A0
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);
SerialLCD slcd(11,12);
int t=0;
int h=0;

void setup() {
  slcd.begin();
  Serial.begin(9600);
  slcd.backlight();
}

void loop() {
  float h = dht.readHumidity();
  float t = ((dht.readTemperature()*1.8)+32);
  if (isnan(t) || isnan(h)) 
    {
        Serial.println("Failed to read from DHT");
    } 
    else 
    {
        Serial.print("Humidity: "); 
        Serial.print(h);
        Serial.print(" %\t");
        Serial.print("Temperature: "); 
        Serial.print(t);
        Serial.println(" *F");
    }
  slcd.home();
  slcd.print(" TEMP: ");
  slcd.print(t);
  slcd.setCursor(0,1);
  slcd.print("HMDTY: ");
  slcd.print(h);
}

And here is my problem, the LCD does not display the sensor readings, just random characters:
https://drive.google.com/file/d/0B1Kkf4HgZKj4MkVTd2d6Qm5qRVE/edit?usp=sharing

I can tell the problem is not the sensor, when I check the serial monitor i get good readings:
https://drive.google.com/file/d/0B1Kkf4HgZKj4dXhiWFhjLUdEM0U/edit?usp=sharing

I'm not sure if this would be useful, but here are the wiki's for the sensor and the display:
http://www.seeedstudio.com/wiki/index.php?title=Grove_-_Serial_LCD_V1.0
http://www.seeedstudio.com/wiki/Grove_-_Temperature_and_Humidity_Sensor_Pro

I was hoping someone could point in the right direction to fix it. Like I said, I'm pretty new to this, I have a feeling I'm missing something basic, but this problem has stumped me for awhile now.

Thanks-
Trey Chaffin

2

And if you try the LCD in a simple "hello world" sketch?
does it fails too?

3

No, I've gone through all the tutorial sketches that came with the LCD, they all work fine. It's just not display the sensor readings correctly on the LCD. When I check the serial monitor, which I have programmed to show the sensor readings, it shows them correctly. :stuck_out_tongue:

4

slcd.begin();

maybe you need to set the baud rate of slcd explicitly?

slcd.begin(9600);