Fetching the data from a rangefinder and applying a command for a servo

Abdelrahman_Ammar · January 26, 2022, 3:00pm

i have a reading of a distance sensor, and i would like to apply a command for a servo>

Example: if the the distance less than 10 cm, the servo turns once

geofrancis · January 26, 2022, 3:08pm

yes you should find everything you need in the set servo example and the rangefinder example.

ArduPilot/ardupilot/blob/ArduPlane-stable/libraries/AP_Scripting/examples/servo_scan.lua

-- move a servo in a sinisoidal fashion

local SERVO_FUNCTION = 94
local PERIOD = 0.5

function update() -- this is the loop which periodically runs
  local t = 0.001 * millis():tofloat()
  local pi = 3.1415
  local output = math.sin(pi * t * PERIOD * 2.0)
  local pwm = math.floor(1500 + 500 * output)
  SRV_Channels:set_output_pwm(SERVO_FUNCTION, pwm)
  return update, 20 -- reschedules the loop at 50Hz
end

return update() -- run immediately before starting to reschedule

github.com

ArduPilot/ardupilot/blob/ArduPlane-stable/libraries/AP_Scripting/examples/rangefinder_test.lua

-- This script checks RangeFinder

local rotation_downward = 25
local rotation_forward = 0

function update()
  local sensor_count = rangefinder:num_sensors()
  gcs:send_text(0, string.format("%d rangefinder sensors found.", sensor_count))

  for i = 0, rangefinder:num_sensors() do
    if rangefinder:has_data_orient(rotation_downward) then
      info(rotation_downward)
    elseif rangefinder:has_data_orient(rotation_forward) then
      info(rotation_forward)
    end
  end

  return update, 1000 -- check again in 1Hz
end

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Abdelrahman_Ammar · January 30, 2022, 2:21pm

Can i do it just using the parameter list in Mission planner ?

geofrancis · January 30, 2022, 2:54pm

there is no parameter for turning a servo when i rangefinder distance is below a set value.