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Srf08

tehmoordartehmoordar Posts: 52
edited 2005-03-11 15:26 in BASIC Stamp
hi,
my range sensor was working fine and now it is showing me everything zero,-- zero range and zero light
once I try to change the address it also does not --- but once I switch on its led blinks twice -- IS it bad sensor or some thing else wron-- any one having any idea-- please help
Thankyou

Comments

  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-03-09 01:10
    It is possible that you blew out part of the sensor or damaged it somehow. Is it running through a regulated voltage, or just off a battery pack?
  • tehmoordartehmoordar Posts: 52
    edited 2005-03-09 15:53
    Hi,
    Infact I am using HP DC power supply-- it was working fine -- and meanwhile I was working on other part of the robot and other sensor and it was only hooked in -- no program runing it---but now once I tried to test it suddenly it stopped giving any signal.
    Do you have any idea?
    Thankyou
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-03-09 16:55
    Check the pinouts. I assume that you didn't drop it or it gett hit on something. It could be that you aren't providing enough power to the sensor. Enough to power the initial LEDs, but not the ultrasonic transducer.

    Post Edited (Robert Schwartz) : 3/9/2005 9:10:47 PM GMT
  • tehmoordartehmoordar Posts: 52
    edited 2005-03-09 18:14
    Hi,
    I can read voltages at SDA and SCL not 5V exactly but like 4.4V and even if I increase the input voltage it stays same on these pins-- what do you say
    Thankyou
  • JonbJonb Posts: 146
    edited 2005-03-09 18:38
    Hi, I've inlcuded the code I use to test srf08/10.

    As for power, the srf08 is known to be power hungry when pulsing out. One suggestion I found on the forum was to add a large capacitor between the negative and positive terminals to absorb some of the drain... might help.

    Also make sure the "new addition" to your circuit isnt causing the problem. Work piece by piece.



    Post Edited (Jonb) : 3/9/2005 6:59:51 PM GMT
    bsx
    bsx
    srf10test.bsx
    5K
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-03-09 22:06
    I meant are you delivering the required current to the srf08:
    Power on.................................275mA..... 3uS
    +/- 10v generator Stabilization..25mA...... 600uS
    8 cycles of 40kHz "ping"...........40mA...... 200uS
    Ranging..................................11mA...... 65mS max
    Standby..................................3mA........indefinite
  • tehmoordartehmoordar Posts: 52
    edited 2005-03-10 16:15
    In power supply I tried to increase the voltage and amp-- to me it look there is no current drainage in the srf08---not consuming any current although once I measure voltages across its sda amd scl it has voltages(5V) --- as you specified step by step power consumption -- there is no power consumption --to me it look like that this sensor is no more good-- what do you say
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-03-11 00:53
    There could be a short in one of the connections. Check for broken or bridged traces. If there is 0 current draw, it definately sounds like something is wring with the sensor. It draws 3ma even when doing nothing in standby.
  • tehmoordartehmoordar Posts: 52
    edited 2005-03-11 14:54
    yes you are right, both of its SDA and SCL should not be high simultaneouly one should be low ---am I wrong in this theory?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-03-11 15:26
    Depends on state ... when there is no communication between an I2C master and slave both lines will be idle and pulled-high. You could connect a 'scope and watch the transactions. What you should see is the master sending commands, then responses (on the SDA line) from the slave.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
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