display: detect display availability

(cherry picked from commit 922b47ca8fdd495b8b2835e9ab5b6430982e1735)

scripts/planktoscope/display.py

@@ -16,20 +16,25 @@ import planktoscope.uuidName
 
 
 class Display(object):
+    display_available = True
+
     def __init__(self):
         # Raspberry Pi pin configuration:
         RST = None  # on the PiOLED this pin isnt used
-
+        try:
             # 128x32 display with hardware I2C:
             self.__disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST)
 
             # Initialize library.
             self.__disp.begin()
-
             self.display_machine_name()
             logger.success("planktoscope.display is ready!")
+        except Exception as e:
+            logger.error("Could not detect the display")
+            self.display_available = False
 
     def display_machine_name(self):
+        if self.display_available:
             self.__clear()
             machineName = planktoscope.uuidName.machineName(
                 machine=planktoscope.uuidName.getSerial()
@@ -37,6 +42,7 @@ class Display(object):
             self.display_text(machineName.replace(" ", "\n"))
 
     def display_text(self, message):
+        if self.display_available:
             text = message.replace("\n", " ")
             logger.info(f"Displaying message {text}")
 
@@ -93,12 +99,14 @@ class Display(object):
             self.__disp.display()
 
     def __clear(self):
+        if self.display_available:
             logger.trace("Clear the display")
             # Clear display.
             self.__disp.clear()
             self.__disp.display()
 
     def stop(self):
+        if self.display_available:
             logger.info("Display is out!")
             self.display_text("Cut the power\nin 5s")