In this tutorial we are going to design a Barometric Pressure Measuring System using BMP180 and ARDUINO. First of all for interfacing BMP180 to ARDUINO, we need to download a library specifically designed for BMP180. This library is available at: https://github.com/adafruit/Adafruit-BMP085-Library After attaching that library, we can call special functions which will ease working with BMP180 sensor.
Hardware: Arduino uno board, connecting pins, 220Ω resistor, BMP180 Barometric Pressure Sensor, 16×2 LCD, bread board.
Software: Arduino nightly
Circuit Diagram & Working Explanation
After calling for header we don’t need to worry for establishing communication between Arduino Uno and BMP180 sensor. We can simply call in special functions which will do that for us. We only need to Initialize an LCD and show the called values from SENSOR on it.
In 16×2 LCD there are 16 pins over all if there is a back light, if there is no back light there will be total 14 pins. One can power or leave the back light pins. Now in the 14 pins there are 8 data pins (7-14 or D0-D7), 2 power supply pins (1&2 or VSS&VDD or GND&+5v), 3rd pin for contrast control (VEE-controls how thick the characters should be shown) and 3 control pins (RS&RW&E).
In the circuit, you can observe that I have only took two control pins, the contrast bit and READ/WRITE are not often used so they can be shorted to ground. This puts LCD in highest contrast and read mode. We just need to control ENABLE and RS pins to send characters and data accordingly.
The connections which are done for LCD are given below:
PIN1 or VSS to ground
PIN2 or VDD or VCC to +5v power
PIN3 or VEE to ground (gives maximum contrast best for a beginner)
PIN4 or RS (Register Selection) to PIN8 of ARDUINO UNO
PIN5 or RW (Read/Write) to ground (puts LCD in read mode eases the communication for user)
PIN6 or E (Enable) toPIN9 of ARDUINO UNO
PIN11 or D4 to PIN10 of ARDUINO UNO
PIN12 or D5 to PIN11 of ARDUINO UNO
PIN13 or D6 to PIN12 of ARDUINO UNO
PIN14 or D7 to PIN13 of ARDUINO UNO
The ARDUINO IDE allows the user to use LCD in 4 bit mode. This type of communication enables the user to decrease the pin usage on ARDUINO, unlike other the ARDUINO need not be programmed separately for using it in 4 it mode because by default the ARDUINO is set up to communicate in 4 bit mode. In the circuit you can see wehave used 4bit communication (D4-D7). [Also check: Interface LCD with Arduino Uno]
So from mere observation from above table we are connecting 6 pins of LCD to controller in which 4 pins are data pins and 2 pins for control.
For connecting the BMP180 to Arduino Uno we need to do following: