Photoresistor help

Comments

• dandreae Posts: 1,375

  2008-08-18 14:10 edited 2008-08-18 14:10

  In Chapter 6 of the "Robotics with the Boe-Bot" it explains how the photoresistors work.· Based on the value of the photoresistor you can create a subroutine that puts the BASIC Stamp in "Sleep" mode.· The Sleep mode puts the BASIC Stamp into a low power mode for up to 18 hours.· You can find more information regarding the "SLEEP" command in the "BASIC Stamp Syntax and Reference Manual.
  
  Dave
  
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  Dave Andreae
  
  Parallax Tech Support·
• Shy Posts: 15

  2008-08-18 16:04 edited 2008-08-18 16:04

  Thank you for reply. i want the robot to remain in sleep mode·during the period
  , thephotoresistors remain in shadow. but when light falls on·robot it should wake up·
• Tracy Allen Posts: 6,667

  2008-08-18 17:22 edited 2008-08-18 17:22

  The SLEEP command will be in a loop in your program. It goes into low power mode for say 1 minute, wakes up briefly to check the light level, and either go back to sleep for another minute or activate.
  
  DO
  SLEEP 60
  GOSUB seethelight
  LOOP UNTIL light > threshold
  
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  Tracy Allen
  www.emesystems.com
• Shy Posts: 15

  2008-08-19 00:24 edited 2008-08-19 00:24

  Thanks again, Please tell me
  
  DO
  SLEEP 60
  GOSUB seethelight
  LOOP UNTIL light > threshold
  
  is it the complete code, i am little confused about subroutine·{·GOSUB seethelight} , please explaine
• Franklin Posts: 4,747

  2008-08-19 01:23 edited 2008-08-19 01:23

  Shy said...
  is it the complete code, i am little confused about subroutine·{·GOSUB seethelight} , please explaine
  

  This is not the whole code, just the part that sleeps while dark the GOSUB would go to code you write that does the things when it is light.
  
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  - Stephen
• Shy Posts: 15

  2008-08-19 12:05 edited 2008-08-19 12:05

  i am attaching here code, please insert in photoresistor command, you have told me,·in it

  bs2

  bs2

  RoamingWithPING-V1.0.bs2

  12K

  RoamingWithPING-V1.0.bs2 12.5K
• Tracy Allen Posts: 6,667

  2008-08-19 17:51 edited 2008-08-19 17:51

  Do you have a photoresistor? What is its electrical resistance at the light level that would be the border between lignt and dark? The code you have is basically the Ping demo written by Andy Lindsay at Parallax, and it does not yet have any provision for the light sensor.
  
  You can connect the photoresistor in series with a fixed resistor from Vdd to Vss, and the junction to a Stamp pin, so that PBASIC will read 1 on that pin in the dark and 0 in the light. You have to discover the correct value of fixed resistor or provide more information about your photoresistor.
  
  

               fixedR     photoR
     +5 ---/\/\---o---/\/\---- Vss
                      |
                      p0
  

  
  
  
  Then at the end of the main loop, add the lines marked with "<

  ---

  ":
  
  

  Main:
  DO
  
    FREQOUT 8, 1, 38500                   ' Emit 38.5 kHz IR To Left
    irDetectLeft = IN9                    ' Store IR Detection Values
  
    FREQOUT 2, 1, 38500                   ' Emit 38.5 kHz IR To Right
    irDetectRight = IN0                   ' Store IR Detection Values
  
    IF (irDetectLeft = 0) AND (irDetectRight = 0) THEN
      GOSUB Ping_Around                   ' Object Detected via IR Forward
    ELSEIF (irDetectLeft = 0) THEN
      GOSUB Ping_Around                   ' Object Detected via IR Left
    ELSEIF (irDetectRight = 0) THEN
      GOSUB Ping_Around                   ' Object Detected via IR Right
    ENDIF
  
    counter = counter + 1                 ' Increment Passive Counter
  
    IF counter > 10 THEN                  ' Wait For 10 Servo Pulses
      GOSUB Ping_Out                      ' Activate PING)))
    ENDIF
  
    IF (distance > 30) THEN               ' Is Object Farther Than 30 cm?
      GOSUB Forward_Pulse                 ' If Yes Go Forward
    ELSE
      GOSUB Ping_Around                   ' Otherwise Scan For Clear Path
    ENDIF
  
    dark PIN 0   ' <------- whatever pin you want to use for the light sensor
    DO WHILE dark  ' <-------  this will only execute when it is dark, pin level high
      SLEEP 60  ' <-------   sleep in increments of 60 seconds
    LOOP    ' <-------    recheck for light once a minute, and back to work when light
  
  LOOP
  

  
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  Tracy Allen
  www.emesystems.com
• Shy Posts: 15

  2008-08-20 15:01 edited 2008-08-20 15:01

  thanks Allen it works.