BMP085 - Barometric Pressure Sensor

8 December 2018 - 0 Comments

BMP085 Pressure Sensor

BMP085 Pinout

BMP085 is sensor from BOSCH used for sensing Barometric Pressure and Temperature. The device is designed for high precision measurements and low power consumption making it ideal for advanced mobile applications.

Pin configuration

BMP085 is an eight pin device as shown in pin diagram and the functioning of each pin is shown below. Usually the device is used developed as a module and then used in circuits for convenience. These modules each of them has different pin out but they are share the same pins and can be matched with the device.

Pin	Name	Function
1	Ground	This pin is connected to ground
2	EOC	EOC (End Of Conversion) pin is used as an indicator to speed up conversion time
3	Vdda	Positive power supply is connected to this pin
4	Vddd	Digital power supply pin is tied together with Vdda pin and connected to power
5	NC	No Connection
6	SCL	I2C interface - Serial Clock pin
7	SDA	I2C interface - Serial Data pin
8	XCLR	Master clear pin (Active low)

Features and Electrical characteristics

Low cost device
High precision
Temperature sensor included
Robust package
Low power: 5μA at 1 sample / sec. in standard mode
I2C interface
Fully calibrated
Pb-free, halogen-free and RoHS compliant
Pressure range: 300 ... 1100hPa (+9000m ... -500m above sea level)
Operating voltage range: 1.8V to 3.6V
Operating temperature range: -40ºC to +85ºC
Conversion time temperature: 4.5ms maximum
Conversion time pressure: 25.5ms maximum

Similar Sensors

BMP180, BME280, BMP280

BMP085 Overview

BMP085 is basically used where you want to accurately measure atmospheric pressure and temperature. Although the device is accurate it has been outdated as there are more accurate models in BMP series in the market. In those modules present in market, BMP180 measures barometric pressure more accurately.

BMP085 is specifically designed to consume very less power and so it can be used battery operated on systems like smart watches and mobile phones. Also the device communicated via serial interface which makes it suitable to be interface in modern microcontroller and microprocessor easily.

How to use BMP085 Pressure Sensor

The typical application circuit for the device BMP085 is given below.

BMP085 Pressure sensor application circuit

As shown in circuit diagram three pins are connected between microcontroller and the device. In them only two pins are used to communicate with the module and this communication is I2C interface. The data is sent to the module or received from the module though this I2C interface. So we have to get the information of barometric pressure and temperature through this interface. For establishing this I2C interface all you need to do is connect SDA of module to SDA pin of µC (microcontroller) and SCL pin of module to SCL of µC (microcontroller).

The setup can be powered from voltage source of +1.8V to +3.6V but for convenience choose a 3.3V power source.

Once the connections are done all you need to program the microcontroller to communicate with module. For establishing communication easily we will use libraries which are pre written for the module. Using these libraries makes the communication easy, all you need to do is download these libraries and call up on them in programs. Once the header file is included, you can use simple commands to send or receive data from the module.

Once the data is received from the module we can use the data (Which represent barometric pressure and temperature) as desired in the program. Hence this way we can use BMP085 to measure barometric pressure.