I2C communication between Pixhawk and Arduino

amitkumar · April 14, 2021, 6:30am

Hiiii
I have 4 analog sensors. I have read the analog output of all sensors using Arduino Uno. now I want to write all sensor data using I2C protocol into another microcontroller that also has I2C.

This means I read analog sensor output and write this data into Pixhawk I2C port.

Can anyone guide me on how can I write sensor data into the Pixhawk I2C port and view this data in mission planner?

iampete · April 14, 2021, 10:05am

Scripting!

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/i2c_scan.lua

-- This script scans for devices on the i2c bus
local address = 0
local found = 0

local i2c_bus = i2c.get_device(0,0)
i2c_bus:set_retries(10)

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

  i2c_bus:set_address(address)

  if i2c_bus:read_registers(0) then
      gcs:send_text(0, "Found I2C at " .. tostring(address))
      found = found + 1
  end

  address = address + 1
  if address == 127 then
    address = 0
    gcs:send_text(0, "Found " .. tostring(found) .. " devices")

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amitkumar · April 14, 2021, 10:17am

Thank You…

Can you explain how this code work. ?
i have read analog sensor data on Pin A0, A1,A2, A3

iampete · April 14, 2021, 10:33am

If its analog in, you can also read that directly with scripting,

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/analog_input_and_GPIO.lua#L29


-- there are a few combinations of PWM in that will not work
-- this is due to the way interrupts are handled, AUX 1 and 6 cannot both
-- be PWM at once because they use the same interrupt (on Cubes), this should fail
if not pwm_in_fail:set_pin(55) then -- AUX 6
  gcs:send_text(0, "Failed to setup PWM in on pin 55")
end


gpio:pinMode(51,1) -- set AUX 2 to output, gpio:pinMode(51,0) would be input


function update()
  gcs:send_text(0, string.format("voltage: %0.2f, PWM: %i, input: ", analog_in:voltage_average(), pwm_in:get_pwm_us()) .. tostring(gpio:read(51)))


  -- analog_in:voltage_average() the average voltage since the last call
  -- analog_in:voltage_latest() the latest voltage reading
  -- analog_in:voltage_average_ratiometric() the average ratiometric voltage (relative to the board 5v)


  -- pwm_in:get_pwm_us() the latest pwm value in us
  -- pwm_in:get_pwm_avg_us() the average pwm value in us since the last call


  -- gpio:read(pin)
  -- gpio:write(pin, state)

amitkumar · April 14, 2021, 10:46am

Sir, Pixhawk AUX4, AUX5, AUX6 i already used for relay ON/OFF