Can a 4-pin HC-SR04 ultrasonic sensor be used on the parallax board, i.e. with PropellerC?

Comments

• erco Posts: 20,261

  2016-01-19 03:24 edited 2016-01-19 03:27

  dakotaknut:
  
  Welcome to the forums! Yes, you can use those sensors with an Activity board. The PING is a much higher quality unit, but we've all been tempted by those $1 HC-SR04s. Like the PING shown at http://learn.parallax.com/activitybot/build-and-test-ping-sensor-circuit, you'll power it with 5V and use two resistors to interface to the 3.3V Propeller.
  
  The four pin HC-SR04 has seperate TRIGger and ECHO pins, requiring two Prop I/O pins. BUT... there is a top secret, insider-exclusive, eyes-only, password-protected, secret-handshake-required, simple one-resistor modification to make it function on just one I/O pin. See this long-winded thread with lots of juicy info: http://forums.parallax.com/discussion/comment/1301893/#Comment_1301893
  
  
• dakotaknut Posts: 9

  2016-01-19 03:36

  OK, I found a sample that looks promising.
  https://gist.github.com/flakas/3294829#file-hc-sr04-ino-L82
  
  There are some build problems
  Serial.begin doesn't work, but I don't think I need it
  
  OUTPUT, LOW, and HIGH are all problems.
  The example didn't show the header file I would need.
  I am looking for examples of the use of these.
  For example pinMode([pin], OUTOUT);
  and digitalwrite([pin], LOW);
  
  LOW and HIGH are undoubtedly as simple as 0 and 1.
  I recollect seeing OUTPUT in an example sometime back when I was working on this a little bit.
  I would like to use a header file for these. I assume that would be the best.
  
  Thank you
• dakotaknut Posts: 9

  2016-01-19 03:58

  Hey, thank you, because my sample doesn't seem to be panning out like I was thinking it might.
  I can't wait to take a look at this.
• anxanywhere Posts: 1

  2020-04-21 13:39 edited 2020-04-21 13:54

  Probably no one is still after this anymore, but I was able to use a 4-pin HC-SR04 with Propeller Activity Board (this was based on https://gist.github.com/flakas/3294829#file-hc-sr04-ino-L82 code)
  

  #include "simpletools.h"
  
  /* HC-SR04 Sensor
     https://www.dealextreme.com/p/hc-sr04-ultrasonic-sensor-distance-measuring-module-133696
    
     This sketch reads a HC-SR04 ultrasonic rangefinder and returns the
     distance to the closest object in range. To do this, it sends a pulse
     to the sensor to initiate a reading, then listens for a pulse 
     to return.  The length of the returning pulse is proportional to 
     the distance of the object from the sensor.
       
     The circuit:
  	* VCC connection of the sensor attached to +5V
  	* GND connection of the sensor attached to ground
  	* TRIG connection of the sensor attached to digital pin 14
  	* ECHO connection of the sensor attached to digital pin 15
  
  
     Original code for Ping))) example was created by David A. Mellis
     Adapted for HC-SR04 by Tautvidas Sipavicius
  
     This example code is in the public domain.
   */
  
  const int trigPin = 14;
  const int echoPin = 15;
  
  int main()
  {
    while(1)
    {
      // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
      // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
      low(trigPin);
      pulse_out(trigPin, 10);
  
      // Read the signal from the sensor: a HIGH pulse whose
      // duration is the time (in microseconds) from the sending
      // of the ping to the reception of its echo off of an object.
      long tEcho = pulse_in(echoPin, 1);
  
      // convert the time into a distance
      int inDist = tEcho / 148;
      int cmDist = tEcho / 58;
  
      print("%d inch\n", inDist);
      print("%d cm\n", cmDist);
    
      pause(200);
    }  
  }
  
• Publison Posts: 12,366

  2020-04-21 17:15

  Welcome back after 4 years. All working code is most welcome. The HC-SR04 is pretty prevalent on ebay.