[Dprglist] Arduino Code Troubles

Pat Caron patcaron at mail.com
Sat Dec 18 07:10:53 PST 2021


Hi David, I have been scratching my head on that very question.
I do remember testing with 200 as a replacement for maxDistance without
success.
I believe I was using || instead of "or" in my comparison at the time.
I will go back and test with ||.
...Pat C.

On Fri, Dec 17, 2021 at 11:20 PM David P. Anderson via DPRGlist <
dprglist at lists.dprg.org> wrote:

> Pat,
>
> This was my earlier suspicion, which is why I asked what happened if you
> replaced the maxDistance with an explicit 200.  You said it had the same
> problem.  How can that be?
>
> just curious
>
> David
>
>
> On 12/17/21 7:42 PM, Pat Caron via DPRGlist wrote:
>
> * [EXTERNAL SENDER]*
> Thanks everyone for the help.  This is now working as expected.
> maxDistance was being overwritten to 0 in what I thought was a disabled
> function.
>
> if ((cm[x] == 0) or (cm[x] > maxDistance)) {
>       cm[x] = 999;
>     }
> Output:
> --- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
> maxDistance = 200
> cm[0] = 0
> cm[1] = 92
> cm[2] = 91
> cm[3] = 90
> cm[4] = 249
> | us_Left = 999cm | us_Mid = 92cm | us_Right = 91cm | ir_Left = 90cm |
> ir_Right = 999cm | Time = 46mS
> ...Pat C.
>
> On Fri, Dec 17, 2021 at 8:16 PM Pat Caron <patcaron at mail.com> wrote:
>
>> I did another quick test removing the cm[x] == 0 condition & leaving the
>> > 200 instead of maxDistance.
>> if ((cm[x] > 200)) {
>>       cm[x] = 999;
>>     }
>> This also worked as expected.
>> Output:
>> --- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
>> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
>> cm[0] = 0
>> cm[1] = 92
>> cm[2] = 91
>> cm[3] = 90
>> cm[4] = 248
>> | us_Left = 0cm | us_Mid = 92cm | us_Right = 91cm | ir_Left = 90cm |
>> ir_Right = 999cm | Time = 46mS
>>
>> I then put maxDistance back in without the cm[x] == 0 and it failed!
>> if ((cm[x] > maxDistance)) {
>>       cm[x] = 999;
>>     }
>> --- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
>> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
>> cm[0] = 0
>> cm[1] = 93
>> cm[2] = 91
>> cm[3] = 90
>> cm[4] = 250
>> | us_Left = 0cm | us_Mid = 999cm | us_Right = 999cm | ir_Left = 999cm |
>> ir_Right = 999cm | Time = 46mS
>>
>> ...Pat C.
>>
>> On Fri, Dec 17, 2021 at 7:34 PM Pat Caron <patcaron at mail.com> wrote:
>>
>>> So I did a quick test removing the second condition
>>>
>>> if ((cm[x] == 0)) { // or (cm[x] > maxDistance)) {
>>>       cm[x] = 999;
>>>     }
>>>
>>> This is working!  Now I need to find out why the > maxDistance condition
>>> is causing the failure.
>>> Output:
>>> --- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
>>> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
>>> cm[0] = 0
>>> cm[1] = 93
>>> cm[2] = 91
>>> cm[3] = 90
>>> cm[4] = 252
>>> | us_Left = 999cm | us_Mid = 93cm | us_Right = 91cm | ir_Left = 90cm |
>>> ir_Right = 252cm | Time = 46mS
>>>
>>> On Fri, Dec 17, 2021 at 5:35 PM Rud Merriam via DPRGlist <
>>> dprglist at lists.dprg.org> wrote:
>>>
>>>> Okay, so we know it is happening in the handling of the conditional.
>>>> Run it twice. Once with the test for maxDistance removed and once with the
>>>> test for equality removed. Also, add a print out of *maxDistance*.
>>>> Need to make sure it is not being changed although the test with '200'
>>>> there should show it isn't.
>>>>
>>>> If you get the same results I'm going to start drinking.
>>>>
>>>> Actually, I'll start wondering about the build process. I'm not
>>>> familiar with PlatformIO. The Arduino IDE takes all the files, rearranges
>>>> them, and then compiles the resulting file. That's unlike most C++ build
>>>> systems. The "rearranging" can lead to some strange issues.
>>>>
>>>> -73 -
>>>> *Rud Merriam K5RUD*
>>>> *Mystic Lake Software*
>>>> <http://secure-web.cisco.com/1L_tRh7d2I9r0OgjobcEuIU_IszpkQq_xbnOiEo1x0nbY9Kmp2qUGFRPorl51SZ-ZHIkthbQu-To2vCaw9oOiALtmhVTyFIXFLRTHcR9EkjyUtrNpHSakTKr6Uj09uzEvHz4rdHGu-pUwtf2BnB8MzwvDtOB8AEW6bvFLLTlcxn9mIJVrIWzHFx6qWEdDQO7WlZp0o7MiiOfdfPBacztARRd6XRfPu1sC1Kos0sgy3jCKwVWqVG2fZr47Jfgq8mbJTBzu76UP-wSrG4e9Beay0pN_4HkJT7ybLCmgh_9LHOQ/http%3A%2F%2Fmysticlakesoftware.com%2F>
>>>>
>>>> On 12/17/21 3:18 PM, Pat Caron via DPRGlist wrote:
>>>>
>>>> Here is the output from Rud's changes:
>>>>
>>>> --- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
>>>> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
>>>> cm[0] = 0 0 999 999
>>>> cm[1] = 95 95 999 999
>>>> cm[2] = 91 91 999 999
>>>> cm[3] = 84 84 999 999
>>>> cm[4] = 251 251 999 999
>>>> cm[0] = 0 0 999 999
>>>> ...Pat C.
>>>>
>>>> On Fri, Dec 17, 2021 at 4:04 PM John Swindle via DPRGlist <
>>>> dprglist at lists.dprg.org> wrote:
>>>>
>>>>>
>>>>> From: Rud Merriam via DPRGlist <dprglist at lists.dprg.org>
>>>>> To: dprglist at lists.dprg.org
>>>>> Cc: Rud Merriam <rudmerriam at gmail.com>
>>>>> Sent: Fri, Dec 17, 2021 2:35 pm
>>>>> Subject: Re: [Dprglist] Arduino Code Troubles
>>>>>
>>>>> Obviously somethine strange happening. Grasping at a straw try
>>>>> replacing the 'or' in the conditional with '||'. It shouldn't make a
>>>>> difference but....
>>>>> Started to make othere suggestions to localize the problem but to much
>>>>> verbiage. Here is what I would try:
>>>>>
>>>>>   for (uint8_t x = 0; x < (SONAR_NUM + IR_NUM); x++) {
>>>>>     Serial.print("cm[");
>>>>>     Serial.print(x);
>>>>>     Serial.print("] = ");
>>>>>     Serial.print(cm[x]);
>>>>>     Serial.print(" ");
>>>>>
>>>>>     if ((cm[x] == 0) || (cm[x] > maxDistance)) {
>>>>>       Serial.print(cm[x]);	//
>>>>>       Serial.print(" ");
>>>>>
>>>>>       cm[x] = 999;
>>>>>
>>>>>       Serial.print(cm[x]);	//
>>>>>       Serial.print(" ");
>>>>>
>>>>>     }
>>>>>
>>>>>     Serial.println(cm[x]);
>>>>>   }
>>>>>
>>>>>
>>>>>
>>>>> -73 -
>>>>> *Rud Merriam K5RUD*
>>>>> *Mystic Lake Software*
>>>>> <http://secure-web.cisco.com/1L_tRh7d2I9r0OgjobcEuIU_IszpkQq_xbnOiEo1x0nbY9Kmp2qUGFRPorl51SZ-ZHIkthbQu-To2vCaw9oOiALtmhVTyFIXFLRTHcR9EkjyUtrNpHSakTKr6Uj09uzEvHz4rdHGu-pUwtf2BnB8MzwvDtOB8AEW6bvFLLTlcxn9mIJVrIWzHFx6qWEdDQO7WlZp0o7MiiOfdfPBacztARRd6XRfPu1sC1Kos0sgy3jCKwVWqVG2fZr47Jfgq8mbJTBzu76UP-wSrG4e9Beay0pN_4HkJT7ybLCmgh_9LHOQ/http%3A%2F%2Fmysticlakesoftware.com%2F>
>>>>>
>>>>> On 12/17/21 10:13 AM, Pat Caron via DPRGlist wrote:
>>>>>
>>>>>
>>>>> What I meant to say last night is the array size is cm[8].  The values
>>>>> for SONAR_NUM == 3 and IR_NUM == 2
>>>>> This should not be overrunning the array as it only loops through 5
>>>>> times.
>>>>> I have tried setting maxDistance as uint32_t without any difference.
>>>>> I have commented out the sendData() function and added some
>>>>> Serial.print statements prior to reassigning the values. (shown in output)
>>>>>
>>>>> #define SONAR_NUM 3
>>>>> #define IR_NUM 2
>>>>> uint32_t cm[8] = {0,0,0,0,0,0,0,0}; // Create array
>>>>> uint16_t maxDistance = 200; // Also used with NewPing.h libraray
>>>>> char *position[] = {"us_Left", "us_Mid", "us_Right", "ir_Left",
>>>>> "ir_Right", "cm[5]", "cm[6]", "cm[7]"};
>>>>> .
>>>>> . // Other code here
>>>>> .
>>>>>
>>>>> void oneSensorCycle() { // Sensor ping cycle complete, do something
>>>>> with the results.
>>>>>   for (uint8_t x = 0; x < (SONAR_NUM + IR_NUM); x++) {
>>>>>     Serial.print("cm[");
>>>>>     Serial.print(x);
>>>>>     Serial.print("] = ");
>>>>>     Serial.println(cm[x]);
>>>>>     if ((cm[x] == 0) or (cm[x] > maxDistance)) {
>>>>>       cm[x] = 999;
>>>>>     }
>>>>>   }
>>>>>   if (troubleshoot) {
>>>>>     for (uint8_t i = 0; i < (SONAR_NUM + IR_NUM); i++) {
>>>>>       Serial.print("| ");
>>>>>       Serial.print(position[i]);
>>>>>       Serial.print(" = ");
>>>>>       Serial.print(cm[i]);
>>>>>       Serial.print("cm ");
>>>>>     }
>>>>>     Serial.print("| ");
>>>>>     Serial.print("Time = ");
>>>>>     Serial.print(elapsedMillis);
>>>>>     Serial.print("mS");
>>>>>     Serial.println();
>>>>>   }
>>>>>   //else {
>>>>>   //  sendData();
>>>>>   //}
>>>>> }
>>>>>
>>>>>
>>>>> Loop() {
>>>>>   .// other code
>>>>>   oneSensorCycle()
>>>>>   . // more code
>>>>> }
>>>>>
>>>>> Serial output:
>>>>>
>>>>> -- Miniterm on /dev/ttyUSB-sensors  115200,8,N,1 ---
>>>>> --- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
>>>>> cm[0] = 0
>>>>> cm[1] = 95
>>>>> cm[2] = 91
>>>>> cm[3] = 85
>>>>> cm[4] = 246
>>>>> | us_Left = 999cm | us_Mid = 999cm | us_Right = 999cm | ir_Left =
>>>>> 999cm | ir_Right = 999cm | Time = 44mS
>>>>>
>>>>> ...Pat C
>>>>>
>>>>>
>>>>> On Fri, Dec 17, 2021 at 10:07 AM Chris Netter <netterchris at gmail.com>
>>>>> wrote:
>>>>>
>>>>> The for loop stops at x < 8, so it won’t overrun.
>>>>>
>>>>> What if you remove the sendData() call?  Does that help?
>>>>>
>>>>> Also,  make sure you have declared any global variables which are
>>>>> modified by interrupts or other tasks as “volatile”, otherwise the compile
>>>>> may decide to optimize away parts of your code.
>>>>>
>>>>> Chris
>>>>>
>>>>> *From: *Doug Paradis <paradug at gmail.com>
>>>>> *Sent: *Thursday, December 16, 2021 11:46 PM
>>>>> *To: *Chris Netter <netterchris at gmail.com>
>>>>> *Cc: *Pat Caron <patcaron at mail.com>; dprglist at lists.dprg.org
>>>>> *Subject: *Re: [Dprglist] Arduino Code Troubles
>>>>>
>>>>> Pat,
>>>>>     for (uint8_t x = 0; x < (SONAR_NUM + IR_NUM); x++) {
>>>>>
>>>>>     If  SONAR_NUM _ IR_NUM = 8 then you are overrunning the array
>>>>> which goes 0 to 7.
>>>>>
>>>>> Regards,
>>>>> Doug P.
>>>>>
>>>>> On Thu, Dec 16, 2021 at 8:53 PM Chris Netter via DPRGlist <
>>>>> dprglist at lists.dprg.org> wrote:
>>>>>
>>>>> So Markus and Karim already pointed out that the original code snipped
>>>>> works as designed.
>>>>>
>>>>> It’s also been pointed out already that you are mixing data types. I
>>>>> don’t think that’s the issue, but worth trying to make both the array and
>>>>> maxDistance uint16_t
>>>>>
>>>>> As for this new code snippet:
>>>>>
>>>>> I don’t see any obvious issue with the for loop.  Are you positive
>>>>> that SONAR_NUM + IR_NUM == 8 ?   if not, you are overshooting the
>>>>> array and that can cause all kinds of non-obvious issues.
>>>>>
>>>>> Also, what does sendData() do?  Could it have some side-effects?
>>>>> Maybe its causing a stack overflow, array bounds overflow, or similar,
>>>>> which in turn causes non-obvious issues?
>>>>>
>>>>>
>>>>>
>>>>> *From: *Pat Caron via DPRGlist <dprglist at lists.dprg.org>
>>>>> *Sent: *Thursday, December 16, 2021 9:04 PM
>>>>> *To: *dprglist at lists.dprg.org
>>>>> *Subject: *Re: [Dprglist] Arduino Code Troubles
>>>>>
>>>>> Hi guys, here is a better example to show what is happening taken from
>>>>> actual code:
>>>>>
>>>>> .... other code
>>>>>   for (uint8_t x = 0; x < (SONAR_NUM + IR_NUM); x++) {  // SONAR_NUM +
>>>>> IR_NUM = 8
>>>>>     if ((cm[x] == 0) || (cm[x] > maxDistance)) {
>>>>>       cm[x] = 999;
>>>>>     }
>>>>>   sendData();
>>>>>   }
>>>>>
>>>>> Printed values cm[0] to cm[5] (us_Left to ir_Right) without the above
>>>>> if statement
>>>>> | us_Left = 0cm | us_Mid = 95cm | us_Right = 51cm | ir_Left = 84cm |
>>>>> ir_Right = 252cm | Time = 45mS
>>>>>
>>>>> Printed values cm[0] to cm[5] with the above if statement
>>>>> \| us_Left = 999cm | us_Mid = 999cm | us_Right = 999cm | ir_Left =
>>>>> 999cm | ir_Right = 999cm | Time = 44mS
>>>>>
>>>>> ...Pat C
>>>>>
>>>>> On Thu, Dec 16, 2021 at 8:45 PM Karim Virani <pondersome64 at gmail.com>
>>>>> wrote:
>>>>>
>>>>> It's doing what it's coded to do
>>>>>
>>>>> On Thu, Dec 16, 2021 at 7:42 PM Pat Caron via DPRGlist <
>>>>> dprglist at lists.dprg.org> wrote:
>>>>>
>>>>> Hi Murray, I did try that with the same results.  NewPing.h library is
>>>>> looking for a uint16_t although it didn't complain when I tried that.
>>>>>
>>>>> ...Pat C
>>>>>
>>>>> On Thu, Dec 16, 2021 at 8:35 PM Murray Altheim via DPRGlist <
>>>>> dprglist at lists.dprg.org> wrote:
>>>>>
>>>>> Hi Pat,
>>>>>
>>>>> What if you define maxDistance as uint32_t?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Murray
>>>>>
>>>>> On 17/12/21 2:27 pm, Pat Caron via DPRGlist wrote:
>>>>> > Hi guys, I'm looking for help with the following Arduino code.
>>>>> >
>>>>> >      uint32_t cm[8] = {0,0,0,0,0,0,0,0}; // Create array
>>>>> >      uint16_t maxDistance = 200; // Also used with NewPing.h library
>>>>> >      .
>>>>> >      . // Other code here
>>>>> >      .
>>>>> >      irSensorL.read(); // Read IR sensor... This is working!
>>>>> >      cm[3] = irSensorL.ranging_data.range_mm/10; // This returns 268
>>>>> >      if (cm[3] > maxDistance) {
>>>>> >        cm[3] = 999;                 /
>>>>> >      }
>>>>> >      Serial.println(cm[3]);  / cm[3] value is always = 999
>>>>> >      sendData();
>>>>> >
>>>>> > The cm[3] value is always 999 when I run this.
>>>>> > If I comment out the if cm[3]... statement cm[3] value is then 268.
>>>>> >
>>>>> > ...Pat C
>>>>> >
>>>>> > _______________________________________________
>>>>> > DPRGlist mailing list
>>>>> > DPRGlist at lists.dprg.org
>>>>> > http://lists.dprg.org/listinfo.cgi/dprglist-dprg.org
>>>>> >
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>> .........................................................................
>>>>> Murray Altheim <murray18 at altheim dot com>                       =
>>>>> =  ===
>>>>> http://www.altheim.com/murray/
>>>>> <http://secure-web.cisco.com/14lOvdPcUGlPjP2ivAKeY8mIi9d295v8OaWJdPND2YjUJlBfNoOO3lETTilwP_3nz0RxT_U1mFErnHiwcJer8prIocqg1sJt81nvC7gdyvvJu7aQwIQEMibN8VF9PjYveDL1bpo-ujILuQozSyYctFPs7EbE9iq2qYCLgM7cqbhW1o1TCZJILl9ZYfxcnrU8lgsJgJNKGYbSIQXO1xsNWAGR_pVFbNDn02LdLUm-BM_5vLawr0NVyH33Qv4Bc5esdpP5qVQcKHPoVlY-u4XYg3siPzxpb5tlZzRxG_qE5Ma8/http%3A%2F%2Fwww.altheim.com%2Fmurray%2F>
>>>>>                                    ===  ===
>>>>>                                                                     =
>>>>> =  ===
>>>>>      In the evening
>>>>>      The rice leaves in the garden
>>>>>      Rustle in the autumn wind
>>>>>      That blows through my reed hut.
>>>>>             -- Minamoto no Tsunenobu
>>>>>
>>>>> _______________________________________________
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>>>>
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