This precision sensor from Bosch is the best low-cost sensing solution for measuring barometric pressure and temperature. Because pressure changes with altitude you can also use it as an altimeter.
The sensor is soldered onto a PCB with a 3.3V regulator, I2C level shifter and pull-up resistors on the I2C pins. The BMP180 is the next-generation of sensors from Bosch, and replaces the BMP085. The good news is that it is completely identical to the BMP085 in terms of firmware/software/interfacing - you can use any example code/libraries for BMP085 as a drop-in replacement.
Specification
- Pressure sensing range: 300-1100 hPa (9000m to -500m above sea level)
- Up to 0.03hPa / 0.25m resolution
- -40 to +85°C operational range, +-2°C temperature accuracy
As for the supply of the BMP180, according to the technical characteristic sheet the supply voltage must be in the range of 1.8V to 3.6V.
However, these modules come with a 3.3V XC6206 series voltage regulator.
This type of regulator is LDO (Low Dropout Regulator).
The most important parameter of a voltage regulator is the voltage drop that tells us how much more voltage must be supplied to the regulator to obtain the desired 3.3 V at the output.
For example, the XC6206 of 3.3V tells us that at least we have to have an input voltage of 3.3V + 0.35 V which tells us that you need a voltage of 3.65 V for the regulator to function correctly.
Thanks to this voltage regulator you can power your BMP180 sensor with a voltage of 5 V like the outputs that have Arduino UNO or Arduino Nano.
Regarding the consumption of the sensor will depend on the mode of operation. The BMP180 can operate in 5 different modes to calculate atmospheric pressure. Temperature obtaining only supports standard mode.
Selecting one mode or another affects consumption, conversion time, and resolution based on the table below.
| WAY | RESOLUTION | CONSUMPTION | TIME |
|---|---|---|---|
| Ultra low power mode | 16-bit | 3 μA | 4.5 ms |
| Standard mode | 17-bit | 5 μA | 7.5 ms |
| High resolution mode | 18-bit | 7 μA | 13.5 ms |
| Ultra high resolution mode | 19-bit | 12 μA | 25.5 ms |
| Advanced resolution mode | 19-bit | 32 μA | 76.5 ms |
Maximum values.
During conversion, peaks of 1 mA are reached, that is, the BMP180 sensor consumes 1A the time it takes to convert atmospheric pressure. In the worst case you will be consuming 1A for 76.5 ms and then return to normal mode consumption.
Finally, the BMP180 sensor includes an I2C interface that allows us a very simple connection with Arduino through two single cables.
The I2C address of the module is 0x77.
- VCC: is the pin through which the module is fed. Although the BMP180 sensor supports a voltage of between 1.8V and 3.6V, thanks to the regulator you can power the module with a voltage between 3.3V and 5V.
- GND: ground pin. It connects directly with Arduino GND.
- SCL: I2C protocol clock signal.
- SDA: I2C protocol data signal.
