Data logger for weather parameters at Arducopter

wayansuparta · December 14, 2020, 2:53pm

Dear Ardupilot Team,

I am a newbie to this technology. I will plan to characterize the atmosphere by putting meteorology sensors to Arducopter like pressure, altitude, temperature, relative humidity, wind speed, and solar radiation. My question is as below.

How to connect all these sensors to Ardupilot?
How to record all these parameters every 5 seconds like in the data logger where the data in the format of csv or txt?

Your advice and solution by showing the link of references, coding, hardware, etc. are highly appreciated.

Thank you.

Best regards,

WS

amilcarlucas · December 14, 2020, 5:50pm

The easiest way is to use a RasberryPiZero or something like that, and example source code from the meteorology device manufacturer.

The harder and better way to do it is to connect it directly to the flight controller and write device drivers for them.

Take a look at the wiki on how to add device drivers to ardupilot.

aamadeuss · December 14, 2020, 11:30pm

Ii also highly recommended to do that separate. You can use the position information of the flightcontroler through mavelink to connect your sensor readings. Raspberry pi is perfect for that.

I also use such a setup with heated rotorblades against icing if it gets humid and cold.

iampete · December 15, 2020, 12:06am

You can also use scripting to log directly to a file on the SD card.

wayansuparta · December 15, 2020, 12:57am

Thank you for the kind response. It means, we can use Arduino for data logger? How to connect between Ardupilot and Arduino?
As I newbie, I still learn how to connect multiple sensors to Ardupilot. Later, the data from mission planning can be saved in the SD card or Laptop. Your idea to solve this problem practically is highly appreciated.

wayansuparta · December 15, 2020, 1:02am

Thank you for the good ideas. This is Ardupilot will be connected to Raspberry Pi? Do have any links or document for the connection? Your idea to solve this problem practically is highly appreciated.

wayansuparta · December 15, 2020, 1:05am

Thank you for the suggestion. My plan is to enhance Ardupilot for atmospheric sensing. What is scripting? It is listing programs or additional devices to be connected to Ardupilot? Your idea to solve this problem practically is highly appreciated.

iampete · December 15, 2020, 1:29am

Scripting is lua code that can run in parallel to the main flight code that can do more or less anything in a safe sandbox where a code crash will not result in a vehicle crash. (you can still crash a vehicle from scripting if you set params or do other odd stuff)

https://ardupilot.org/copter/docs/common-lua-scripts.html

There are already a example of logging UART data,

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/Serial_Dump.lua

-- this script reads data from a serial port and dumps it to a file
local file_name = 'raw serial dump.txt'
local file_name_plain = 'serial dump.txt'
local baud_rate = 9600

-- find the serial first (0) scripting serial port instance
-- SERIALx_PROTOCOL 28
local port = assert(serial:find_serial(0),"Could not find Scripting Serial Port")

-- make a file
local file = assert(io.open(file_name, "w"),"Could not create file " .. file_name)
file = assert(io.open(file_name_plain, "w"),"Could not create file " .. file_name)
file:close()

-- begin the serial port
port:begin(baud_rate)
port:set_flow_control(0)

function update() -- this is the loop which periodically runs

This file has been truncated. show original

I2C support is coming soon, https://github.com/ArduPilot/ardupilot/pull/14276

Just need analogue support and you can log more or less anything you could connect to a Arduino, you can also trivially sync with flight information such as position and altitude.

wayansuparta · December 15, 2020, 1:44am

Thank you, Peter. Great and very helpful. Let me learn first the idea. If you have other ideas that can be easily implemented is welcome. Have a wonderful day ahead.

aamadeuss · December 15, 2020, 9:05am

There are multiple options if you go for the raspberry pi solution.
You can connect the pixhawk through serial, and could just exchange a NMEA string (GPS), depending on your needs this could be enough, or you get the full mavlink (the craft attitude could be interesting for the radiance sensor, even with a cosine receptor, this will likely influence your reading). Add your sensors to the raspberry pi (trough i2c, serial, analog) then make a simple python script that writes all your sensor reading in a file every x seconds. should take a student around 2-3 days to make it work reliably with some error handling.

wayansuparta · December 15, 2020, 9:43am

Dear Hans Bert,

Thank you so much for the great idea. Now, I can confirm that using Raspberry Pi to embed the meteorological sensors is more feasible and it would be connected to Ardupilot. Can BME280 sensors connected directly to board of Ardupilot? Or, still use Raspberry Pi? Thank you for your time.

aamadeuss · December 15, 2020, 9:47am

Hey,
both is possible.
But for connecting the sensors to ardupilot you need to write your own driver.
To connect it to raspberry pi there are already solutions out there.

Its posible to connect all sensors to ardupilot and its maybe more “nice” and “clean” to do that, but it is a lot more efford. having all sensors connected to the raspberry pi and only one serial connection to ardupilot is a lot more flexible.

wayansuparta · December 15, 2020, 3:08pm

As suggested by Amilcar Lucas, this is confirmed I will use Raspberry Pi Zero. I just found the connection between Ardupilot and RPI at https://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html. My question, is the battery between RPI and Ardupilot should be separated?

aamadeuss · December 15, 2020, 8:19pm

I would use the same battery, but a seperate 3A 5v BEC for the Raspberry Pi Zero.