How to read the potentiometer value before it is moved for the first time

[brodhaq]

Hello,
strange issue here. I am using the following code to control my panel backlight using a potentiometer connected to Arduino which is connected to AirPlayer Raspberry.

Code: Select all

function LIGHTING_pots()
	POT_LIGHT_circuit_1 = hw_adc_input_read(LIGHT_circuit_1)
	POT_LIGHT_circuit_2 = hw_adc_input_read(LIGHT_circuit_2)
	POT_LIGHT_circuit_3 = hw_adc_input_read(LIGHT_circuit_3)
	xpl_dataref_write("whateverdataref...", "INT", var_round(POT_LIGHT_circuit_1))
	xpl_dataref_write("whateverdataref 2...", "INT", var_round(POT_LIGHT_circuit_2))
	xpl_dataref_write("whateverdataref 3...", "INT", var_round(POT_LIGHT_circuit_3))
end

LIGHT_circuit_3 = hw_adc_input_add("ARDUINO_MEGA2560_A_A4", LIGHTING_pots) --POTENTIOMETER LIGHTING CIRCUIT III
LIGHT_circuit_2 = hw_adc_input_add("ARDUINO_MEGA2560_A_A5", LIGHTING_pots) --POTENTIOMETER LIGHTING CIRCUIT II
LIGHT_circuit_1 = hw_adc_input_add("ARDUINO_MEGA2560_A_A6", LIGHTING_pots) --POTENTIOMETER LIGHTING CIRCUIT I

It works just great, but only after the potentiometer is moved for the first time after the x-plane starts. If I position the potentiometer to for example 50% and restart x-plane, the dataref is initialized at 100% value (which is a default SASL behavior in this case), and until I first touch the potentiometer, the light is shining like crazy. After I first move the potentiometer by a tiny bit, it immediately jumps to the correct value.

Is there any code I could use to force Air Player to reload the potentiometer values without me touching them?

Thank you!
Pavel

[Keith Baxter]

Hi

You are using "hardware" you need to right to the sim the value of hardware on initialization.

Keith

[JackZ]

Hi.

Try to add an initial call to
LIGHTING_pots()
at startup early in your code, to force a hardware read.

The following calls to the function will be done when operating the pot.

Jacques

[Keith Baxter]

Hi.

Try to add an initial call to
LIGHTING_pots()
at startup early in your code, to force a hardware read.

The following calls to the function will be done when operating the pot.

Jacques

Yes my point.

Keith

[Sling]

Pavel,

The hw_adc_input_add() callbacks should be independent. They each return their own value as an argument to the callback function. You can then do as the guys have suggested and use the read function to do a single read of the pot positions and write to the datarefs during instrument start.

What you have with the start up mod added will work but why read and update all pots every time when only one changes at a time.

Tony

[JackZ]

@Sling Good point, having three separate functions allows to operate each pot individually
@brodhaq Your code would be better as follow:

Code: Select all

function LIGHTING_pot_1()
	POT_LIGHT_circuit_1 = hw_adc_input_read(LIGHT_circuit_1)
	xpl_dataref_write("whateverdataref...", "INT", var_round(POT_LIGHT_circuit_1))
end

function LIGHTING_pot_2()
	POT_LIGHT_circuit_2 = hw_adc_input_read(LIGHT_circuit_2)
	xpl_dataref_write("whateverdataref 2...", "INT", var_round(POT_LIGHT_circuit_2))
end

function LIGHTING_pot_3()
	POT_LIGHT_circuit_3 = hw_adc_input_read(LIGHT_circuit_3)
	xpl_dataref_write("whateverdataref 3...", "INT", var_round(POT_LIGHT_circuit_3))
end

-- initialization of pot values at startup --
LIGHTING_pot_1()
LIGHTING_pot_2()
LIGHTING_pot_3()
--rest of the code...

-- Hardware declarations
LIGHT_circuit_3 = hw_adc_input_add("ARDUINO_MEGA2560_A_A4", LIGHTING_pot_1) --POTENTIOMETER LIGHTING CIRCUIT III
LIGHT_circuit_2 = hw_adc_input_add("ARDUINO_MEGA2560_A_A5", LIGHTING_pot_2) --POTENTIOMETER LIGHTING CIRCUIT II
LIGHT_circuit_1 = hw_adc_input_add("ARDUINO_MEGA2560_A_A6", LIGHTING_pot_3) --POTENTIOMETER LIGHTING CIRCUIT I

Jacques

[Sling]

Yes like that other than you need to declare the hardware before trying to read from it. So swap those last couple of blocks.