Week 4 (S1"11)

Tamiya Ball Castor

Description

• 12mm diameter
• Selectable height (25mm and 35mm)
• Plastic casing
• Light application
• Comes in 2pcs/set
• 
  
  
  
  Line Sensor (LSS05)
  Descriptions: This newly developed Auto-calibrating line sensor is super easy to use. Come with 5 pairs of IR transmitter and receiver, it can covers line detection of 1cm to 3cm wide, dark color or bright color line. With 1 press, it will start "recognizing" the surface under it, calibrating the threshold between dark and bright. it takes 4 to 5 seconds only. After that, it is done, being stored in internal non volatile memory, it will still "recognize" the line even after power off and on again. Come with connector and wires.

  
  

  Features:

  • 5V power
  • 5 digital output reprsenting logic of 5 IR sensor
  • 1 press to start calibration
  • 2 press to toggle logic into Dark On mode, to sense dark line
  • 3 press to toggle logic into Bright On mode, to sense bright line
  • Calibration button for easy of calibration
  • Combine with MC40A for line following robot development

  
  

  
  LSS05  (Low cost  line sensor bar) consists of 5  IR  transmitter and  IR  receiver pairs. LSS05 is the typically used for embedded system or robots in line following task. LSS05 can be used for either dark or bright line following. Any color with distinct brightness difference is suitable for LSS05.
  
  The IR transmitters on LSS05 are pulsed to allow the transmitter to off at certain idle period of sensor. This is to minimize the current consumption of LSS05 to at least half of the current  consumption  compared  to  a  normal  unregulated  IR  line  sensor.  Power  polarity protection is available on LSS05 in case the user accidently applies a reverse voltage. 

  
   LSS05  have  5  digital  outputs  to  user  indicating  the  existence  of  the  line.  The threshold  to  the brightness of  line existence will be set when  the user calibrate the sensor  to the surface that it will recognize. One digital input of calibration signal is available to user for automated calibration  function by  the user system. User can pull down  this signal  line with microcontroller  to  calibrate  the  sensors.  This  signal  line  also  can  be  use  to  enter  different mode of LSS05. Each  sensor of  the 5  sensors on LSS05  is  independent of  each other. The refreshing  rate  of  the  sensors  is more  than  100Hz.  Every  sensor  is  provided with  its  own LEDs as indication of line detection. 
  
  LSS05  has  a  manual  calibration  button.  The  calibration  button  is  multifunctional. User can enter different mode of functions using calibration button  too as  the alternative  to the calibration signal.   

    
  

  
  

   

  A – Sensor indicator LEDs (red) will light up showing that it detects line. 
  
  B – Calibration button  is used  to  enter different modes. Press once  to  enter  the calibration mode. Press twice to set the line sensor bar into dark line following mode and press 3 times to set the line sensor bar into bright line mode.
  
  C – Mode indicator LED (orange) is for indication of the mode. LED will light up if LSS05 is in bright line detection mode. Otherwise, it is off. 
  
  D – PIC16F819 PIC microcontroller for data processing.
  
  E – Power and output signal connector
  
  F – Power indicator LED (green) showing the board is supplied with power. Maximum input power is 5V.
    

   

   A – Pairs of IR sensor which consist IR transmitter and IR receiver.
  
  B – It is reserved for Manufacturing Test Point. Please DO NOT short or connect wire to any of these pins.
  
  C –Input/output signal label showing the Power (5V, GND), output signal pins (O1-O5) and calibration signal (Cal.).  

   

  LSS05 cable connector
  
  Figure below shown cable used to connect LSS05 to microcontroller. 2020H-08 connector is used at the end of the cable.
   

  

  Pin pitch for 2020H connector  is not standard size for donut board pin pitch. To use LSS05 with donut board, simply cut  the end of connector and solder another  type of connector  like 2510  or  3960  connector. Following  figure  is  showing  the  step  to  connect LSS05  to  others type of connector.

  
  

  

  
  

   

  Figure below shown LSS05 was connected to donut board.  

  

  
  
  GETTING STARTED
  
  LSS05 need to be calibrated to retrieve the dark and bright value of the surface that it will do the line follow. Every of the IR sensor pairs need to be exposed to the dark and bright surface  for  it  to  read  the value  and  save  it. LSS05 will  save  the value  in EEPROM,  it will retrieve  back  the  data  from  the  EEPROM  every  time  its  switch  on. Hence,  only  one  time calibration  is  needed  for  the  same  surface  and  line.  To  calibrate  LSS05,  simply  press  the calibration push button once or pulling down  the Cal. for few milliseconds. Calibration will be start by exposing the sensor to the bright surface and then to the dark surface as indicated by the LEDs. 3 LEDs blinking means the bright calibration (2.5 seconds) and 2 LED blinking means  the  dark  calibration  (2.5  seconds).   Calibration  is  normally  done  by  crossing  every sensor across  the line  that  it will follow as shown  in  the figure below. Sensors will save  the brightest value  in  the bright  calibration process  and darkest value  in dark  calibration. User can  calibrate by  simply  swinging  the  sensors  across  the dark and bright  surface  in order  to expose  every  sensor  to  the  dark  and  bright  surface.    Calibration  of  every  sensor  is independent and value of each sensor will be saved.

  
  

   

  Example motions of calibration by crossing the sensor between the lines.  

  
  

   1. Calibration button and signal.
   

  The calibration button or the calibration signal (Cal.) has 2 functions. The 1st function is to call for calibration of the line sensor and the 2nd function is to set whether the sensor bar will operate for dark line following or bright line following.  

  
  

  2. Using the calibration push button
  
  Press the push button once to set the sensor bar into calibration mode. LSS05 will go into calibration mode and the red LEDs will start blinking accordingly to  indicate whether it is calibrating for dark color or bright color. 
  
  Press the push button twice will set the line sensor into dark line following mode which LSS05 will detect dark line. Sensor indicator LEDs will light up if it detects dark surface (the line is dark).
  
  Press  the push button 3  times will  set  the  line  sensor bar  into bright  line  following mode which LSS05 will detect bright  line;  sensor  indicator LEDs will  light up  if  it detects bright surface (the line is bright). Dark/Bright indicator (D/B) indicator LED will light up in orange color for this mode. 
  
  3. Using the calibration signal
  
  The calibration signal  from  the sensor connector can be used  to perform exactly  the same  function  as  the  calibration  push  button.  The  calibration  signal  line  requires  user  to generate falling edges to set for appropriate mode.  LSS05 detect how many falling edges to set to appropriate mode.
  
  •  One falling edge pulse for calibration mode as shown in figure below. After the falling edge pulse the sensor will start calibration.

  
  

  

  •  Two falling edges for setting the LSS05 into dark line mode. The 2 falling edges need to be in range of 1.5 seconds.

  
  

  

  •  3 falling edges for setting the LSS05 into dark line mode. The 3 falling edges need to
  be in range of 1.5 seconds. 

   

   

  
  

  *Reminder: Please keep the Cal. signal at high logic level 5V if it’s not generating pulse for the function of the signal.