The scope should show the response from the ECHO pin (a brief pulse) and a scaled version of the distance. Did you connect the ECHO pin of the module via a resistor divider? What resistor values did you use for that? This wiring diagram was made for a Bela (not BelaMini) but it should be clear how the resistor divider should be wired.

@Tractor could you please try the example linked above (which uses a digital out for the TRIG out instead of analog as you may've been using so far(?)) and see if it works for you?

Yes! I see something in the scope red vertical line that moves from left to right. Although doesn't seem to be affeted by my proximity to the sensor

    tkay I see something in the scope red vertical line that moves from left to right.

    The red line is the signal from the echo pin. Seeing it is a good thing: it means it's being received. It's position in the screen is pretty much random and shouldn't matter much. There should also be a blue line there (although you may not see it if it's at exactly 0): does it move with distance?

    Also, the console in the main IDE tab should print several times per second. What does it print?

      It doesn't print anything...I have been trying with a 4.7k resistor b/c I don't have 2.2k would that make it not work?

      Once I changed resistor values it started printing something other than zeroes. I used 47 for resistor 1 and 100 for resistor 2 is this not enough division to protect the bela? Would 1k and 2.2 be the ideal set? or 100k and 220 be the same effect? It printed the values shown in the image. The scope shows red lines but no blue ones. is there something missing? could I do a custom render to use this input in Pure Data from a receive object?

      alt text

        tkay g. I used 47 for resistor 1 and 100 for resistor 2 is this not enough division to protect the bela? Would 1k and 2.2 be the ideal set? o

        the division is enough but you are drawing a lot of current for no good reason. See here for recommendations on resistos: https://forum.bela.io/d/1598-fritzing-diagram-for-hc-sr04-to-bela/4 . The ratio is important, but also the minimum value.

        tkay The scope shows red lines but no blue ones. i

        The blue line will display a distance of up to 100cm by default. To see more than that you need to change the scale of the corresponding signal in the scope options or change the /100 in:

        		scope.log(digitalRead(context, n, gEchoDigitalInPin) * 0.5, distance/100);
            10 days later

            Awesome, the sensor is working great now. With the last edit you did. Thanks for that. Now, is there a way to get these readings with this code in a PD via a custom render ? I imagine somebody has done it before?

            the file that you referred to as

            brings up with a bunch of errors despite that I believe it's configured the way I need( d0 d1 output input although it also uses d2 and d3 )I would need to deactivate those so that I can use for other purposes. any reason this one you believe why this one is not working here is the full error messages:

            In file ./include/legacy/UdpServer.h: [warning] You included file UdpServer.h. This is now deprecated. You should instead use #include <libraries/UdpServer/UdpServer.h> [-W#warnings] column: 2, line: 2
            In file ./include/legacy/Midi.h: [warning] You included file Midi.h. This is now deprecated. You should instead use #include <libraries/Midi/Midi.h> [-W#warnings] column: 2, line: 2
            In file ./include/legacy/Scope.h: [warning] You included file Scope.h. This is now deprecated. You should instead use #include <libraries/Scope/Scope.h> [-W#warnings] column: 2, line: 2
            In file ./include/legacy/PulseIn.h: [warning] You included file PulseIn.h. This is now deprecated. You should instead use #include <libraries/PulseIn/PulseIn.h> [-W#warnings] column: 2, line: 2
            no member named 'init' in 'PulseIn' column: 13, line: 317
            no member named 'init' in 'PulseIn' column: 14, line: 319
            In file included from /root/Bela/projects/pd3/render.cpp:15:
            ./include/legacy/UdpServer.h:2:2: warning: You included file UdpServer.h. This is now deprecated. You should instead use #include <libraries/UdpServer/UdpServer.h> [-W#warnings]
            #warning You included file UdpServer.h. This is now deprecated. You should instead use #include <libraries/UdpServer/UdpServer.h>
            ^
            In file included from /root/Bela/projects/pd3/render.cpp:16:
            ./include/legacy/Midi.h:2:2: warning: You included file Midi.h. This is now deprecated. You should instead use #include <libraries/Midi/Midi.h> [-W#warnings]
            #warning You included file Midi.h. This is now deprecated. You should instead use #include <libraries/Midi/Midi.h>
            ^
            In file included from /root/Bela/projects/pd3/render.cpp:17:
            ./include/legacy/Scope.h:2:2: warning: You included file Scope.h. This is now deprecated. You should instead use #include <libraries/Scope/Scope.h> [-W#warnings]
            #warning You included file Scope.h. This is now deprecated. You should instead use #include <libraries/Scope/Scope.h>
            ^
            In file included from /root/Bela/projects/pd3/render.cpp:22:
            ./include/legacy/PulseIn.h:2:2: warning: You included file PulseIn.h. This is now deprecated. You should instead use #include <libraries/PulseIn/PulseIn.h> [-W#warnings]
            #warning You included file PulseIn.h. This is now deprecated. You should instead use #include <libraries/PulseIn/PulseIn.h>
            ^
            4 warnings generated.
            /root/Bela/projects/pd3/render.cpp:317:13: error: no member named 'init' in 'PulseIn'
            pulseIn.init(context, gEchoDigitalInPin, HIGH);

            /root/Bela/projects/pd3/render.cpp:319:14: error: no member named 'init' in 'PulseIn'
    pulseIn2.init(context, gEchoDigitalInPin2, HIGH);
    ~~~~~~~~ ^
2 errors generated.
make: *** [/root/Bela/projects/pd3/build/render.o] Error 1

              Use this one instead.
              Follow instructions to enable analog out instead of digital out if you so wish

              (also note the receiver name is now distance (not distance1))

              • tkay replied to this.

                Awesome, thanks so much. Works beautifuly much better than the pd only methods.

                  Yes, I did try that one. And got useful readings but not as precise

                  hmm that's sad. It would be interesting to compare them side-by-side

                    giuliomoro
                    I found the same as @tkay: as commented elsewhere, regular pulsing jumps in the Pd patch - introducing a kind of yodelling effect - which I tried to filter out. I experimented with the [delay] object for the output and that improved things a bit, but the combined C++/Pd approach still gives much better results.

                      3 years later

                      tkay
                      Hello!
                      I'm back trying to use the HC-SR-04 sensor, this time with a regular full size bela. However I'm getting some errors. I'm not sure if this:

                      giuliomoro this one instead.
                      was meant to be used with the mini only. I am now using the analog out instead and as instructed i commented out the #define ULTRASONIC_DISTANCE_DIGITAL_OUT I connected the echo in (with resistor divider of course) in digital in 8 (pd 19)
                      What am I missing?

                      Here's the full error message:

                      In file render.cpp: no matching function for call to 'sys_doio' column: 3, line: 656
                      In file render.cpp: call to function 'strcmp' that is neither visible in the template definition nor found by argument-dependent lookup column: 11, line: 59
                      /root/Bela/projects/FX/render.cpp:656:3: error: no matching function for call to 'sys_doio'
                      sys_doio();
                      ~~~~
                      /usr/local/include/libpd/s_stuff.h:243:12: note: candidate function not viable: requires single argument 'pd_that', but no arguments were provided
                      extern int sys_doio(struct _pdinstance* pd_that);
                      ^
                      /root/Bela/projects/FX/render.cpp:59:11: error: call to function 'strcmp' that is neither visible in the template definition nor found by argument-dependent lookup
                      if(0 == strcmp(id, db[n].first.c_str()))
                      ^
                      /root/Bela/projects/FX/render.cpp:544:13: note: in instantiation of function template specialization 'getIdxFromId<Trill *>' requested here
                      int idx = getIdxFromId(sensorId, gTouchSensors);
                      ^
                      /usr/include/string.h:140:12: note: 'strcmp' should be declared prior to the call site
                      extern int strcmp (const char *s1, const char *s2)
                      ^
                      2 errors generated.
                      make: *** [/root/Bela/projects/FX/build/render.o] Error 1