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adc/microphone_adc - Read analog values from a microphone and plot the measured sound amplitude. i2c/bmp280_i2c - Read and convert temperature and pressure data from a BMP280 sensor, attached to an I2C bus. i2c/lis3dh_i2c - Read acceleration and temperature value from a LIS3DH sensor via I2C i2c/mcp9808_i2c - Read temperature, set limits and raise alerts when limits are surpassed. i2c/mma8451_i2c - Read acceleration from a MMA8451 accelerometer and set range and precision for the data. i2c/mpl3115a2_i2c - Interface with an MPL3115A2 altimeter, exploring interrupts and advanced board features, via I2C. i2c/oled_i2c - Convert and display a bitmap on a 128x32 SSD1306-driven OLED display i2c/pa1010d_i2c - Read GPS location data, parse and display data via I2C. i2c/pcf8523_i2c - Read time and date values from a real time clock. Set current time and alarms on it. uart/lcd_uart - Display text and symbols on a 16x02 RGB LCD display via UART
42 lines
2.2 KiB
Plaintext
42 lines
2.2 KiB
Plaintext
= Attaching a BMP280 temp/pressure sensor via I2C
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This example code shows how to interface the Raspberry Pi Pico with the popular BMP280 temperature and air pressure sensor manufactured by Bosch. A similar variant, the BME280, exists that can also measure humidity. There is another example that uses the BME280 device but talks to it via SPI as opposed to I2C.
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The code reads data from the sensor's registers every 500 milliseconds and prints it via the onboard UART. This example operates the BMP280 in _normal_ mode, meaning that the device continuously cycles between a measurement period and a standby period at a regular interval we can set. This has the advantage that subsequent reads do not require configuration register writes and is the recommended mode of operation to filter out short-term disturbances.
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[TIP]
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======
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The BMP280 is highly configurable with 3 modes of operation, various oversampling levels, and 5 filter settings. Find the datasheet online (https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmp280-ds001.pdf) to explore all of its capabilities beyond the simple example given here.
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======
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== Wiring information
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Wiring up the device requires 4 jumpers, to connect VCC (3.3v), GND, SDA and SCL. The example here uses the default I2C port 0, which is assigned to GPIO 4 (SDA) and 5 (SCL) in software. Power is supplied from the 3.3V pin from the Pico.
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WARNING: The BMP280 has a maximum supply voltage rating of 3.6V. Most breakout boards have voltage regulators that will allow a range of input voltages of 2-6V, but make sure to check beforehand.
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[[bmp280_i2c_wiring]]
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[pdfwidth=75%]
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.Wiring Diagram for BMP280 sensor via I2C.
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image::bmp280_i2c_bb.png[]
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== List of Files
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CMakeLists.txt:: CMake file to incorporate the example into the examples build tree.
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bmp280_i2c.c:: The example code.
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== Bill of Materials
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.A list of materials required for the example
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[[bmp280_i2c-bom-table]]
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[cols=3]
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|===
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| *Item* | *Quantity* | Details
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| Breadboard | 1 | generic part
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| Raspberry Pi Pico | 1 | https://www.raspberrypi.com/products/raspberry-pi-pico/
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| BMP280-based breakout board | 1 | https://shop.pimoroni.com/products/bmp280-breakout-temperature-pressure-altitude-sensor[from Pimoroni]
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| M/M Jumper wires | 4 | generic part
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|===
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