Reading and Displaying Temperature With an Arduino

Today we are going to walk you through the process of reading temperature with your Arduino and displaying it on a  16x2 character parallel LCD. This set up has many uses including displayign temperatures during home brewing, fish tanks, PC Temperature display etc. The code will scale nicely and it is so simple that a 5 year old can do it. So lets get started! 

Please check your displays data sheet for pin placement. There are a few models with different pin arragements.
 

Connecting the Temperature sensors.

Lets start by connecting the 2 temperature sensors. To do this we need to connect 1 leg of each temperature sensor (or thermistor) to analog pins 0 and 1. Then you must connect each remaining leg to a 10k resistor and then to one of the arduinos ground pins.

Connecting the LCD to the Arduino.

Lets start by connecting power to the backlight.  The 10k trimpot will be used to control the LCD's contrast.

1. Connect LCD pin 16 to the Arduino's ground pin.
2. Connect LCD pin 15 to the Arduino's 5v pin.
3. Connect the 10K trimpots wiper (center pin) to LCD pin 3.
4. Connect one of the remaining 2 legs of the trimpot to the Arduino's 5v pin.
5. Conned the last remaining leg of the trim pot to the Arduino's ground pin.

Now we can connect the data lines from the LCD to the Arduino.

1. Connect LCD pin 1 to the Arduino's ground pin.
2. Connect LCD pin 2 to the Arduino's 5V pin.
3. Connect LCD pin 4 RS to Arduino digital pin 7.
4. Connect LCD pin 5 RW to the Arduino's ground pin. (This is tied to ground because we are not reading any information from the LCD)
5. Connect  LCD pin 6 EN to Arduino digital pin 8
6. Connect LCD pin 11 DB4 to Arduino digital pin 9
7. Connect LCD pin 12  DB5 to Arduino digital pin 10
8. Connect LCD pin 13 DB6 to Arduino digital pin 11
9. Connect LCD pin 14 BD7 to Arduino digital pin 12

Now that we have the LCD hooked up all you need to do is upload the code below to have it disply the temperature from each of the temperature sensors.