How does Eddie Work?

How does Eddie Work?

Like an Inkjet Printer but Different

Eddie works a lot like an Inkjet printer.  However, an inkjet printer prints on paper.  A traditional paper printer uses a roller system to grab on tightly to the paper and feed that paper through at the exact right distance from the print cartridge nozzles to make a perfect print.  As the ink moves across the paper, it slowly moves that paper forward so the cartridge can print the next line.  With Eddie, we don't know what size or height the cookie would be, so we had to develop a way to detect the height and the size of the cookie or print object. 

Height Detection

  1. Four LED “lights” on the right that emit IR (Infrared).  IR light is invisible to the human eye but we normally feel it as heat. The lights on the Eddie are not hot enough to feel.
  2. The Sensor on the left that looks only for IR light. 
  3. First, we move the center of the tongue back even with the LEDs and Sensors.  Then we slowly move the cookie up.
  4. As we move the cookie up we turn on each of the LEDs one at a time and check to see if the sensor can read that LED.  This cycle of checking the 4 LEDs is repeated multiple times rapidly as we move the cookie up.
  5. We stop when LED the sensor can read only the TOP LED. The cookie is now at the perfect distance from the print head. 



 



Centering

  1. After we have set the height, we move it forward until the sensor can see the Lower LED 1-3. That’s the back of the cookie.
  2. Next, we move the cookie back until the sensor can see the lower LED 1-3 again. That’s the front of the cookie.
  3. Using the stepper motor we are able to measure that distance as we move from back to front.
  4. Once we have the length of the cookie we know where to start printing. 

Calibration

  1. Every time the printer starts, we check the ambient light conditions of room at that moment and the brightness of each LED.
  2. We make adjustments to certain internal settings based on this.
  3. Can’t start up the printer with a custom tray installed or a cookie on the tongue.
  4. Restarting the printer often fixes problems.

Video of Height Scan and Centering Process without Scan Large Print Area checked.


Video of Height Scan and Centering Process with Scan Large Print Area Checked





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