[Dprglist] Arduino Code Troubles
John Gauthier
zizumara at sbcglobal.net
Fri Dec 17 14:19:28 PST 2021
Thanks. I had assumed that he was using C, not C++. For C++, that's
even better. =)
On 12/17/2021 4:06 PM, Rud Merriam via DPRGlist wrote:
>
> Since you opened the door (LOL).
>
> Ardino code is C++ so as a C++ pedant I'll suggest a different
> defensive approach... Macros are problematic. I think C allows the
> following.
>
> enum Positions { // might do enum struct Positions : uint8_t {
> US_LEFT = 0, US_MID = 1, US_RIGHT = 2, IR_LEFT = 3. IR_RIGHT = 4 };
> const uint8_t TIME_DIFF {5}; const uint8_t SONAR_NUM {3}; const
> uint8_t IR_NUM {2}; const uint8_t BUFF_SIZE {SONAR_NUM + IR_NUM};
> const uint8_t MAX_DISTANCE {200}; const uint8_t DIST_UNKNOWN {999);
> uint32_t cm[BUFF_SIZE{0}; // will initialize entire array to 0
>
> I'd change the names to be lower case the same as regular variables.
> Using an /enum struct/ can cause challenges since it doesn't convert
> to regular integers so must be cast: /uint8_t(US_LEFT)/. But it is
> safer if you want to enforce its use only as the enum.
>
> -73 -
> *Rud Merriam K5RUD*
> /Mystic Lake Software/ <http://mysticlakesoftware.com/>
>
> On 12/17/21 3:28 PM, John Gauthier via DPRGlist wrote:
>> As a side note, I believe there is great value in defensive
>> programming as a habit. In my code, I always use macros to define
>> constants, especially when using them as indicies of an array
>> representing a message. In this case, you could use
>>
>> #define US_LEFT 0
>> #define US_MID 1
>> #define US_RIGHT 2
>> #define IR_LEFT 3
>> #define IR_RIGHT 4
>> #define TIME_DIFF 5
>> #define BUFF_SIZE 8
>>
>> #define SONAR_NUM 3
>> #define IR_NUM 2
>> #define MAX_DISTANCE 200
>> #define DIST_UNKNOWN 999
>>
>> assert(SONAR_NUM + IR_NUM <= BUFF_SIZE);
>>
>> uint32_t cm[BUFF_SIZE];
>> for (i = 0; i < BUFF_SIZE; ++i) {
>> cm[i] = 0;
>> }
>>
>> irSensorL.read();
>> cm[IR_LEFT] = irSensorL.ranging_data.range_mm / 10;
>> if (cm[IR_LEFT] > MAX_DISTANCE) {
>> cm[IR_LEFT] = DIST_UNKNOWN;
>> }
>>
>> Coding constants with macros makes it hard to make mistakes,
>> especially when making modifications to the code. It also makes reading
>> the code much easier. This was a C coding standard at two companies
>> where I have worked.
>>
>>
>> John G.
>>
>> > 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();
>> On 12/17/2021 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 <mailto:paradug at gmail.com>
>>> *Sent: *Thursday, December 16, 2021 11:46 PM
>>> *To: *Chris Netter <mailto:netterchris at gmail.com>
>>> *Cc: *Pat Caron <mailto: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 <mailto: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/ === ===
>>> = = ===
>>> 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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