pico-bmp180

A code of BMP180 temperature and barometer I2C sensor for supporting Raspberry Pi Pico board

Hello Raspberry PI Pico developers and users, we made a small and simple library BMP180 I2C sensor for Raspberry PI Pico. I didn't find source code of BMP180 sensor for Raspberry Pi Pico board in C/C++, but in python source codes are already exist in internet, so I deciced to write code of BMP180 sensor for supporting Raspberry Pico.

The BMP180 sensor is worked fine with Raspberry Pi Pico board!!!

BMP180 I2C sensor is still popular for Arduino's projects. Moreover, I able buy this sensor freely in current time.

Links of ordering sensor: https://www.amazon.co.uk/UMTMedia%C2%AE-Pressure-Arduino-Precision-Atmospheric/dp/B0983V8115/ref=sr_1_4?crid=13S470NQVCI59&keywords=BMP180+3.3+V&qid=1684018689&sprefix=bmp180+3.3+v%2Caps%2C109&sr=8-4

Prerequisite

• BMP180 with support 3.3 V logic and power
• Raspberry Pi Pico OR Raspberry Pi Pico W
• 4 pcs Male-Male breadboard jumper
• Micro USB cable (which we can connect into laptop)
• Putty software or any serial port terminal software
• Breadboard
• Installed PICO C SDK, cmake and visual studio code (In PICO SDK will install automatically visual studio code IDE, cmake and other essential softwares)

Gallery

A built simplest circuit in breadboard with BMP180 sensor and Raspberry Pi Pico

Screenshot result of air temperature and pressure

Sechmatics and pinouts (I used Fritzing software)

Breadboard

Graphical represenatation schematic with BMP180 and Raspberry Pi Pico in Breadboard

Circuit diagramm

Minimal schematic diagramm for ablity to work BMP180 sensor in any projects

Pinout

Assume: Use minimal circuit diagramm to able work with BMP180 sensor

Sensor: Raspberry Pi Pico

VIN -------> 3.3 V OUT

GND -------> GND

SDA -------> GP4

SCL -------> GP5

Basic code

Minimum amount of code that able work with BMP180 sensor in Raspberry Pi Pico.

Main code of usage example with BMP180 sensor for Raspberry PI Pico board. (You can look in main.c code file)

#include <stdio.h> /* Standard libary for printing the UART console */
#include "pico/stdlib.h" /* Libary of PICO SDK C/C++ for support function for RPI PICO */
#include "bmp180.h" /* Own header of BMP180 */

int main() {

    stdio_init_all(); /* Initialize that supporting printf standard function via UART interface */

    i2c_init_bmp180(); /* Initialize I2C interface for BMP180 sensor */

    for (;;) /* Infinite loops */ 
    {
        data_from_bmp180 current_data = get_bmp180_sensor_data(3); /* Get data from BMP180 sensor */
        
        printf("T: %.1f oC | Pressure: %.1f Pa \r\n", 
                               current_data.air_temperature_in_celisus, 
                               current_data.atmospheric_pressure_in_Pa); /* Print about data of BMP180 in UART console*/

        sleep_ms(1000); /* Delay for 1000 ms */
    }   
}

Building code (We used Linux Mint 21.1 OS)

How get binary file for uploading your Raspberry Pi Pico

1. Download own repository by using command git clone https://github.com/misha-dig/pico-bmp180.git

2. Go to direcitory pico-bmp180 by command cd pico-bmp180

3. Set enviroment path of PICO_SDK_PATH with your pico-sdk directory path by command export PICO_SDK_PATH=/your_sdk_path/pico-sdk

4. Create directory build by command mkdir build

5. Go to build directory by command cd build

6. Hit command cmake ..

7. Hit command make and wait until building code finished

8. Flash into your Raspberry Pi Pico file pico_bmp180.uf2 from build directory (You need first hold a button BOOTSEL until file manager appeared for Raspberry Pi Pico drive)

9. Enjoy your project !!! :) :) :)

How generate doxygen HTML documentation

If you don't have doxygen package in your Linux PC

Please run two simple command (for debian based Linux OS users)

sudo apt-get update

sudo apt-get install doxygen

And genrate doxygen HTML documentation by invoking command in this directory

doxygen

Open your documentation by path html/index.html

Setting UART via USB (after flashing your Raspberry Pi Pico)

We use Pico's setting default speed of UART

The default parameter for Raspberry Pico is

• Baudrate: 115200 bit/s
• Data bit: 8 bit
• Stopbit: 1 bit
• Parity: NONE
• Flow control: XON/XOFF

So we enter 115200 and select serial port in main page of Putty software

How to create own projects with own libary BMP180

Creating empty project with BMP180 sensor library (As similary building instruction above)

We used with instruction how create any project with using Pico C SDK.

1. Clone by hitting command git clone https://github.com/misha-dig/pico-bmp180.git

2. Go to direcitory pico-bmp180 by command cd pico-bmp180

3. Set enviroment path of PICO_SDK_PATH with your pico-sdk directory path by command export PICO_SDK_PATH=/your_sdk_path/pico-sdk

4. Modify project name in CMakeLists.txt file by using text editor (seach and replace all text from pico_bmp180 into your name of project (for example meteostation) and save this text file)

5. Create directory build by command mkdir build

6. Go to build directory by entering command cd build

7. Hit command cmake ..

8. Build your source of code for your project by hitting command make in build directory path

Your existing project

Just you need to follow few step ...

1. Download and unzip own this repository from github OR using git clone https://github.com/misha-dig/pico-bmp180.git

2. Go to directory pico-bmp180

3. Copy bmp180.c and bmp180.h into your existing project directory

4. You may be need to modify your CMakeLists.txt (Such adding file bmp180.c code in section add_executable and add dependencies hardware_i2c in section target_link_libraries )

5. Enjoy your coding!!! :) Good Luck!!!

Credits and resources

Controllerstech. Interface BMP180 with STM32. Controllerstech. https://controllerstech.com/interface-bmp180-with-stm32/ (Tutorial + video training how write code BMP180 I2C sensor stm32)

Bosch Sensortec. (2022, August 15th). Data Sheet BMP180 Digital pressure sensor. https://cdn-shop.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf (Datasheets of sensor BMP180)

Raspberry Pi Ltd. hardware_i2c. https://www.raspberrypi.com/documentation/pico-sdk/hardware.html#hardware_i2c (API Documentation of Raspberry PI Pico C SDK)

Raspberry Pi Ltd. The C/C++ SDK. https://www.raspberrypi.com/documentation/microcontrollers/c_sdk.html#say-hello-world (How create new project with Raspberry Pico)