digital-altimeter-rp2

Digital Altimeter with adjustments for known altitude/sea-level-pressure using Raspberry Pi Pico2 with BMP585(or BMP581, BMP390, BMP280), BME680, OLED Display

Features of this Raspberry Pi Pico 2 code:

• BMP585 (I2C1 #47 addr) - latest generation highly accurate air pressure, temp, and altitude.
  • used as primary sensor for air pressure and altitude
  • now uses my driver code for quick switch between bmp585, bmp581, bmp390
    • https://github.com/bradcar/MicroPython_BMP58x
  • BMP585 is on the same I2C bus as BME680
• BME680 (I2C1 #77 addr) - for inside temp & humidity, air pressure, air quality, and altitude.
• Large 20px fonts.
• SSD1309 (SDI) - uses SSD1306 SW, both SDI & I2C code - SDI is faster
  • ssd1306 Framebuffer-based SW for printing text & blit of bitmap images
• button debounce that uses efficient interrupt code (does not use CPU cycles to spin/wait on button debounce, yay!)
  • Has 3 buttons (1. set/adjust alt/sea-level-pressure, 2. F/Celsius, 3. Big Font Summary or detail summary in small font)
• Temperature from on-board RP2350 (no external pins, ADC4)

Deprecated but easy to switch back to:

• BMP581 (I2C1 #47 addr) - latest generation highly accurate air pressure, temp, and altitude.
  • used as primary sensor for air pressure and altitude
  • now uses my driver code for quick switch between bmp585, bmp581, bmp390
    • https://github.com/bradcar/MicroPython_BMP58x
  • BMP581 is on the same I2C bus as BME680
• BMP390 (I2C1 #76 addr) - previous generation air pressure, temp, and altitude.
  • used as primary sensor for air pressure and altitude
  • on same I2C bus as BME680, solder bump on sensor makes it #76 addr to have code address it distictly from bme680

Useful sites:

• Powering Pico: https://www.youtube.com/watch?v=3PH9jzRsb5E -- feed, 5v for ultrasonics, and power in my car.
  • TODO get Buck converter 12v car to 5v (to usb-b or micro-usb)
  • For micro-USB and/or external power, best to have MosFET protection
    • recommended DMG-2305ux, but this is surface-mount MosFET
    • investigating RLB8721, that way can hook laptop up in car to update SW

Project images:

todo

My code is Based on my Parking sensor

• https://github.com/bradcar/artcar-ultrasonic-dist-rp2

Other useful sites (used in this code):

• MicroPython Fonts of various sizes: https://github.com/peterhinch/micropython-font-to-py/tree/master
• My driver code for quick switch between bmp585, bmp581, bmp390
  • https://github.com/bradcar/MicroPython_BMP58x
• Altitude calculations in my codes use NSF's NCAR formula: https://ncar.github.io/aircraft_ProcessingAlgorithms/www/PressureAltitude.pdf
• IAQ calculation: https://github.com/thstielow/raspi-bme680-iaq

TODOs

• adapt to also become a vertical feet logger for skiing