Arduino UNO-based Active Grille Block

[CigaR007]

I have been working on integrating an active grille into the fibreglass partial grille block.

I went the COTS (commercial-off-the-shelf) route as to speed up the construction. The grille vane assembly is from a Chevrolet Bolt, or Malibu ? It includes only the plastic frame, no actuator-motor. It is a generic brand bought on amazon.

I basically cut it half, added a servo motor and a pair of micro switches (top and bottom).

Pretty basic functionality for the time being (OPEN/SHUT), but I will be integrating the micro switches and an LCD display. Below is the active grille block in action.

https://www.youtube.com/watch?v=PNOai6rMIbs

Stay tuned for more updates in the coming days.

Cheers.

[Piwoslaw]

Nice!

Now I am interested in how the Arduino will control it.

[aerohead]

Originally Posted by Piwoslaw

Nice!

Now I am interested in how the Arduino will control it.

Do the OEM devices use an analog reference voltage input signal at an A-Gate terminal on the circuit board, from which the digital CP decides if any 'action' is to commence or not, based on internal look-up menus, and if so, the digital signal is processed into an analog voltage signal at the output gate, out to the motor, which, when de-energized, is spooled backwards under spring tension at the shutters? With 'fail-wide-open' safety protection?

[CigaR007]

Originally Posted by aerohead

which, when de-energized, is spooled backwards under spring tension at the shutters? With 'fail-wide-open' safety protection?

From what I have seen and read thus far, there does not seem to be fail-safe OPEN mechanism in current grille shutters. I could be wrong though...In their OEM state, all they do is throw a CEL code if there is an issue.

As it stands, there is no spring tension to accommodate a fail-OPEN state, as it would be difficult to use with a servo motor.

Originally Posted by Piwoslaw

Nice!

Now I am interested in how the Arduino will control it.

The arduino control code will evolve over time. For the time being, given my limited coding knowledge, it will be pretty basic.

I managed to integrate a micro switch to detect the shutter position. A 1602 LCD was also integrated to monitor the OPEN/SHUT status.

Things I want to integrate into the code, eventually :

• Coolant temperature
• Ambient temperature
• Rain/Snow sensor

Below is the LCD display and microswitch in action.

https://www.youtube.com/watch?v=wVfX2bUZeNY

Arduino Code :

PHP Code:

#include <Servo.h>
#include <ezButton.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);             // I2C address 0x27, 16 column and 2 rows

// constants 
const int BUTTON_PIN = 7;                       // Arduino pin connected to button's pin
const int SERVO_PIN = 9;                        // Arduino pin connected to servo motor's pin
const int LED_PIN = 2;                          // green LED connected to digital pin 2
const int POS_SWITCH = 4;
Servo servo;                                    // create servo object to control a servo

// variables 
int angle = 0;                                  // the current angle of servo motor
int lastButtonState;                            // the previous state of button
int currentButtonState;                         // the current state of button
int val = 0;                                    // variable to store the read value

void setup() {
  
  Serial.begin(9600);                            // initialize serial
  pinMode(BUTTON_PIN, INPUT_PULLUP);             // set arduino pin to input pull-up mode
  pinMode(LED_PIN, OUTPUT);
  pinMode(POS_SWITCH, INPUT);
  servo.attach(SERVO_PIN);                       // attaches the servo on pin 9 to the servo object
  servo.write(angle);
  lcd.init();                                    // initialize the lcd
  lcd.backlight();   

}

void loop() {

  lastButtonState = currentButtonState;                       // save the last state
  currentButtonState = digitalRead(BUTTON_PIN);               // read new state

  if(lastButtonState == HIGH && currentButtonState == LOW) {
    digitalWrite(LED_PIN, HIGH);                              // turn the LED on (HIGH is the voltage level)
    delay(1000);                                              // wait for a second
    digitalWrite(LED_PIN, LOW);                               // turn the LED off (LOW is the voltage level)
    delay(500);                                               // wait for a 0.5 second

    // change angle of servo motor
    if(angle == 0)
      angle = 90  ;
    else
    if(angle == 90)
      angle = 0;

  servo.write(angle);                                         // control servo motor arccoding to the angle
 }
 
    delay(1000);                                              // wait for a second
 
 val = digitalRead(POS_SWITCH);                               // read the input pin
  if(val == HIGH){
    lcd.clear();                                              // clear display
    lcd.setCursor(0, 0);                                      // move cursor to   (0, 0)
    lcd.print(" GRILLE SHUTTER");                             // print message at (0, 0)
    lcd.setCursor(2, 1);                                      // move cursor to   (2, 1)
    lcd.print("  [ SHUT ]");                                  // print message at (2, 1)
}
  else {
 
    lcd.clear();                                              // clear display
    lcd.setCursor(0, 0);                                      // move cursor to   (0, 0)
    lcd.print(" GRILLE SHUTTER");                             // print message at (0, 0)
    lcd.setCursor(3, 1);                                      // move cursor to   (2, 1)
    lcd.print(" [ OPEN ]");                                   // print message at (2, 1)
                      
}
} 


Cheers !

[Piwoslaw]

Originally Posted by CigaR007

Things I want to integrate into the code, eventually :

• Coolant temperature
• Ambient temperature
• Rain/Snow sensor

I would add A/C on/off, so you have good air flow over its condenser.

[CigaR007]

Are there any downsides to tapping the sensors wiring ? I am inclined to tap near the PCM as to minimize any potential losses. The sensors are mainly outputting a 0-5Vdc, according to the wiring shematics and Honda service manual.

[Piotrsko]

Input resistance of the arduino may or may not affect the original circuit. You won't know until you try it. I'm not fluent in arduino. Adding a very high impedance switch would have a negligable effect by using a mosfet as an isolator since the sense current would be very small.

[CigaR007]

Originally Posted by Piotrsko

Input resistance of the arduino may or may not affect the original circuit.

Turns out that an input can be set to high-impedance; so it should be ok.

Cleaned up a bit of the wiring and made more permanent circuit board to accommodate the servo, LCD display and various switches.



The LCD now has a 3D-printed case, which will make it easier to mount on the centre console.

As it stands, it is a fully functional prototype.

https://www.youtube.com/watch?v=Ewl1qabLvx0

[CigaR007]

Making some progress on the arduino code.

Here is a summary of the code :

Button Press: If the button is pressed, the servo motor angle is adjusted based on the current angle (0, 45, 90 degrees).

Position Switch: Reads the state of the position switch and displays a message on the LCD indicating whether the grille shutter is shut (0), half-open (45), or fully open (90).

Position Error Detection: Reads the state of the position error switch and displays an error message on the LCD if the position is between certain angles and the error switch is triggered

Fully manual for the time being. Sensor integration (coolant and ambient temperatures) will be done after the grille shutter has been installed on the car.

https://www.youtube.com/watch?v=_ANNBYAIONs

[CigaR007]

Cleaned up the wiring and made the permanent control panel.

I am using shielded cat5 cable as the main wiring harness. The wiring from the shutter grille will be custom-made as to make it more waterproof using special connectors.

The connections to the Control panel and board are made using a detachable screw-Terminal to RJ45 connector. Pretty handy for quickly disconnecting the cables and make the necessary changes or troubleshooting, if needed.



Control Panel using a blank housing plate from my CR-Z.






Next step is to work on the shutter grille and install more permanent components such as the waterproof limit switches and Servo motor.