4. APP - LIGHT

Now to control the RGB boards of the Pico 4WD car.

Quick User Guide

1. Run the app_4_light.py file under the pico_4wd_car\examples\app_control path.

2. Based on 2. APP - Car Move, add Button and Switch widgets to the E and F areas as shown below.

   

3. After saving () and connecting () the controller, click to run it.

4. When you use the D-pad widget to make the car move, the tail light will show the direction. The on/off and color of underglow can be controlled through the Switch and Button widgets.

How it works?

This project is based on 2. APP - Car Move with the addition of lighting effects.

1. Here, a total of three lighting effects are added and called in remote_handler().

   def remote_handler():
       global throttle_power, steer_power, move_status, dpad_touched
   
       if dpad_touched:
           my_car_move(throttle_power, steer_power, gradually=True)
   
       ''' no operation '''
       if not dpad_touched:
           move_status = "stop"
           car.move('stop')
   
       # ''' Bottom Lights '''
       bottom_lights_handler()
       # ''' Singal lights '''
       singal_lights_handler()
       # ''' Brake lights '''
       brake_lights_handler()
   

   • bottom_lights_handler(): Controls the on/off and colors of the two RGB boards at the bottom.

   • singal_lights_handler(): Control the left and right RGB LEDs of the rear RGB board, for example, when the car turns left, make the left two LEDs of the rear RGB board light up, and the same for the turn right.

   • brake_lights_handler(): Controls the tail RGB board to light up red in breathing mode when the car stops or brakes.

2. About singal_lights_handler() function.

   • When left is received, make the left two LEDs of the rear RGB board light up orange (singal_on_color).

   • When right is received, make the right two LEDs of the rear RGB board light up orange (singal_on_color).

   • Otherwise, let the left and right LEDs are off (0x000000).

   def singal_lights_handler():
       if move_status == 'left':
           lights.set_rear_left_color(singal_on_color)
           lights.set_rear_right_color(0x000000)
       elif move_status == 'right':
           lights.set_rear_left_color(0x000000)
           lights.set_rear_right_color(singal_on_color)
       else:
           lights.set_rear_left_color(0x000000)
           lights.set_rear_right_color(0x000000)
   

3. About brake_lights_handler() function.

   When stop is received, let the RGB board on the tail light up red(brake_on_color) in breathing mode(The brightness slowly goes from bright to dark and dark to bright.).

   def brake_lights_handler():
       global is_move_last , brake_light_status, brake_light_time, led_status, brake_light_brightness
       global brake_light_brightness, brake_light_brightness_flag
   
       if move_status == 'stop':
           if brake_light_brightness_flag == 1:
               brake_light_brightness += 5
               if brake_light_brightness > 255:
                   brake_light_brightness = 255
                   brake_light_brightness_flag = -1
           elif brake_light_brightness_flag == -1:
               brake_light_brightness -= 5
               if brake_light_brightness < 0:
                   brake_light_brightness = 0
                   brake_light_brightness_flag = 1
           brake_on_color = [brake_light_brightness, 0, 0]
           lights.set_rear_color(brake_on_color)
       else:
           if is_move_last:
               lights.set_rear_middle_color(0x000000)
           else:
               lights.set_rear_color(0x000000)
           is_move_last = True
           brake_light_brightness = 255
   

4. About bottom_lights_handler() function.

   • The variable led_status is True when the widget in the E area is ON, which causes the bottom two RGB boards to light up in a specific color.

   • This specific color is selected from the array (led_theme[]) by tapping on the widget in the F area.

   def bottom_lights_handler():
       global led_status
       if led_status:
           color = list(led_theme[str(led_theme_code)])
       else:
           color = [0, 0, 0]
       lights.set_bottom_color(color)
   

5. And the on_receive(data) function also has some changes based on 2. APP - Car Move.

   • When you tap the D-apd buttons, the return left, right, forward or backward will cause the variable move_status to change simultaneously.

   • This will allow the 3 RGB boards to display different effects as the car move.

   def on_receive(data):
       global throttle_power, steer_power, move_status, dpad_touched
       global led_status, led_theme_code, led_theme_sum
   
       ''' if not connected, skip & stop '''
       if not ws.is_connected():
           return
   
       # Move - power
       if 'Q' in data.keys() and isinstance(data['Q'], int):
           throttle_power = data['Q']
       else:
           throttle_power = 0
   
       # Move - direction
       if 'K' in data.keys():
           #print(data['K'])
           if data['K'] == "left":
               dpad_touched = True
               move_status = 'left'
               if steer_power > 0:
                   steer_power = 0
               steer_power -= int(throttle_power/2)
               if steer_power < -100:
                   steer_power = -100
           elif data['K'] == "right":
               dpad_touched = True
               move_status = 'right'
               if steer_power < 0:
                   steer_power = 0
               steer_power += int(throttle_power/2)
               if steer_power > 100:
                   steer_power = 100
           elif data['K'] == "forward":
               dpad_touched = True
               move_status = 'forward'
               steer_power = 0
           elif data['K'] == "backward":
               dpad_touched = True
               move_status = 'backward'
               steer_power = 0
               throttle_power = -throttle_power
           else:
               dpad_touched = False
               move_status = 'stop'
               steer_power = 0
   
       if throttle_power == 0:
           move_status = 'stop'
   

6. In addition, the on_receive(data) function also responds to widgets in the E and F areas.

   • The widget in the E area is used to turn on/off the bottom RGB boards, while the widget in the F area is used to change colors.

   • Assign the return value of the E area widget to the variable led_status.

   • If led_status is True (the widget in the E area is toggled ON), then determine if the widget in the F area is tapped.

   • If so, switch to the next color in the array led_theme[].

   def on_receive(data):
       global throttle_power, steer_power, move_status, dpad_touched
       global led_status, led_theme_code, led_theme_sum
   
       ''' if not connected, skip & stop '''
       if not ws.is_connected():
           return
   
       ...
       ...
   
       # LEDs switch
       if 'E' in data.keys():
           led_status = data['E']
   
       if led_status:
           # LEDs color theme change
           if 'F' in data.keys() and data['F'] == True:
               led_theme_code = (led_theme_code + 1) % led_theme_sum
               print(f"set led theme color: {led_theme_code}, {led_theme[str(led_theme_code)][0]}")