voltage level for ultrasonic sensor

Discussion in 'Embedded Systems and Microcontrollers' started by ep.hobbyiest, Jan 3, 2017.

  1. ep.hobbyiest

    Thread Starter Member

    Aug 26, 2014
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  2. OBW0549

    Distinguished Member

    Mar 2, 2015
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    The HC-SR04 User Manual says the operating voltage is from 4.5V to 5.5V, so I imagine the answer is "no."
     
  3. ep.hobbyiest

    Thread Starter Member

    Aug 26, 2014
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    Yeah, i meant to ask about TRIG pin of sensor. I saw some schematic online. So, got confused about this.
    They have connected directly 3.3v pin to TRIG pin of sensor.

    So, is it really working ? or they might have different changed design?
     
  4. OBW0549

    Distinguished Member

    Mar 2, 2015
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    Who knows? People do all kinds of things. All you can do is buy one of these devices and try it out; it may work at the lower voltage, or it may not, or it may "sort of" work but not very well. Your guess is as good as mine.
     
  5. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Very Generally Speaking!

    The usual setup is:
    * 0-0.8 volts is digital zero
    * 2.7 or 2.8 volts is digital one

    So. If you follow above, you can connect 5 volt system to 3.3 volt device, and they will work. However, some systems and some devices are more sensitive than others. The only way for you to be sure that the two devices will work with each other is to actually connect them and try using them.
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    If you have the sensor, try it with a 3.3v trigger. The little light should tun on if it is triggered.
     
  7. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    This suggests that the module does require a 5V supply (it deals with interfacing trigger and output to 3.3V uC).
     
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