I am having a bit of trouble reading an NFC card with an ESP32 (using Arduino IDE). I'm using PN532 module, which works pretty well. So far my code looks like:
#include <SPI.h>
#include <PN532_SPI.h>
#include <PN532.h>
#include <NfcAdapter.h>
PN532_SPI pn532spi(SPI, SS);
NfcAdapter nfc = NfcAdapter(pn532spi);
void setup(void) {
Serial.begin(115200);
Serial.println("NDEF Reader");
nfc.begin();
}
void loop(void) {
//Serial.println("\nScan a NFC tag\n");
if (! nfc.tagPresent())
{
return;}
else{
NfcTag tag = nfc.read();
String scannedUID = tag.getUidString();
Serial.println(scannedUID);
}
delay(5000);
}
which is basically just the example from don's ndef library. I just got the UID string, rather than printing all details of the card.
It does work and displays the UID. However, I get a message saying "Tag is not NDEF formatted". Which I don't really care about. I only want to print the UID to serial and then pick this up in a C# windows app. I guess I could just ignore it, but is there a way to stop it showing up?
Is there a better library I should be using?
Thanks
Andrew
I fixed it by modifying the mifareclassic.cpp file which is part of the library. I just commented out the offending line. Probably a better way since it's still doing the check. But will do for now.
Thanks
Andrew
Related
I try to use arduino library from github:
https://github.com/LibreSolar/bq769x0-arduino-library/blob/master/bq769x0.h
but it doesn't even compile.
Error is connected with :
#if BQ769X0_DEBUG
void printRegisters(void);
#endif
When I comment it it compiles, but I need this for debuging of course.
I assume, that this is a simple problem, but I have not much experience with programming. Please help.
I tried commenting it, and i think it works, but than i don't see any results in serial monitor
This is called "conditional compilation". If the preprocessor value BQ769X0_DEBUG is defined, then the bq769x0 class member function printRegisters is declared and defined (i.e. it exists). If BQ769X0_DEBUG is not defined, then that function does not exist and trying to call it is an error.
If you want to use that function, define it before including the header:
#define BQ769X0_DEBUG // Enable debug features
#include <bq769x0.h>
bq769x0 BMS(bq76920, BMS_I2C_ADDRESS);
I'm fairly certain this will work on Arduino as AFAIK, it does not pre-compile libraries.
Note, that if you decide to disable the debug features by not defining it:
// #define BQ769X0_DEBUG
#include <bq769x0.h>
bq769x0 BMS(bq76920, BMS_I2C_ADDRESS);
// BMS.printRegisters does not exist!
it will be an error to later call that function. To fix that, you can use code guards in your code:
void loop()
{
BMS.update(); // should be called at least every 250 ms
#ifdef BQ769X0_DEBUG
BMS.printRegisters();
#endif
}
Another option would be to change the library header from:
#if BQ769X0_DEBUG
void printRegisters(void);
#endif
to
#if BQ769X0_DEBUG
void printRegisters(void);
#else
void printRegisters(void) {}
#endif
In this case, when BQ769X0_DEBUG is not defined, the printRegisters function is created but does not do anything. Calling it won't cause an error.
Or, make your own macro:
#ifdef BQ769X0_DEBUG
#define PRINT_REGISTERS BMS.printRegisters()
#else
#define PRINT_REGISTERS
#endif
Then change the usage to:
void loop()
{
BMS.update(); // should be called at least every 250 ms
PRINT_REGISTERS;
}
Note: this macro is hardcoded to use the BMS object. It would need to be modified to use others.
I am fairly new to coding and especially to C++ but usually with enough googling and breaking problems down to simpler blocks I can figure things out. This issue makes no sense to me though and the solution I just happened to come up with on accident makes even less sense to me.
I am writing a program for ESP32-S in vscode with platformio and broke this down to isolate what was causing the error and found this issue with class/object declaration:
This code will compile but I get a link error twice that says
undefined reference to `point::point()'
#include <Arduino.h>
class point {
public:
point();
point(uint day){
this->_day = day;
}
uint _day;
};
class channel {
public:
channel(String _color, byte _pin){
}
point _points[64];
};
channel red("red", 0);
void setup() {}
void loop() {}
Meanwhile this code with one seemingly unrelated change compiles and links without issue:
#include <Arduino.h>
class point {
public:
point();
point(uint day){
this->_day = day;
}
uint _day;
};
class channel {
public:
channel(){ // <--- Removing the arguments from channel constructor fixes it?
}
point _points[64];
};
channel red(); // <--- And here of course
void setup() {}
void loop() {}
I don't know why that fixes it, and I have a workaround for now if this is what I have to do, but I want to understand. Thanks.
You've declared a constructor point::point(), but not defined it (i.e. it has no body). This is not OK with the linker and that's what you're being told.
There are three ways to fix this.
Don't declare the constructor (compiler generates a default constructor which may or may not initialize the member _day to 0, depending on compiler and platform). Note that you also have the interesting alternative of deleting the default constructor.
Declare and define it to do whatever you consider appropriate.
Give your constructor point::point(uint day) a default argument value, e.g.: point::point(uint day = 0).
Side note on C style arrays of C++ objects like here:
point _points[64];
This is a dangerous combination, unless you know exactly what you're doing. See the C++ FAQ
I am using MPU9250-breakout board with Arduino Uno.
The library I used is from here.
Below is my code.
#include <Arduino_FreeRTOS.h>
#include "mpu9250.h"
MPU9250 IMU(Wire,0x68);
int status;
void task_1(void *pvParameters)
{
(void) pvParameters;
for (;;)
{
}
}
void task_2(void *pvParameters)
{
(void) pvParameters;
for (;;)
{
}
}
void setup() {
Serial.begin(115200);
while(!Serial) {}
status = IMU.begin();
if (status < 0) {
Serial.println("IMU initialization unsuccessful");
Serial.println("Check IMU wiring or try cycling power");
Serial.print("Status: ");
Serial.println(status);
while(1) {}
}
xTaskCreate(
task_2,
(const portCHAR *)"task2", // A name just for humans
128, // Stack size
NULL,
1, // priority
NULL);
xTaskCreate(
task_1,
(const portCHAR *)"task1", // A name just for humans
128, // Stack size
NULL,
1, // priority
NULL);
}
void loop()
{
}
The problem is that when there are two tasks defined, the program will be restarted automatically. But when I comment out task_1, the program works fine. The result value of xTaskCreate is correct.
I guess the problem might be the stack or heap size is too small, but I've increased stack and heap size and it's still doesn't work.
Can anyone tell me where the problem might be from?
At the end of your setup(), you need to start the scheduler:
// Now the task scheduler, which takes over control of scheduling individual tasks, //is automatically started.
vTaskStartScheduler();
That is all I see different between my project which works and yours.
Once you have created your tasks, you have to start scheduler.
Call vTaskStartScheduler() before exiting setup function and after you have created your tasks.
https://www.freertos.org/a00132.html
Just for the info, Arduino-UNO (with ATMega-328P) has very limited RAM and it may happen some tasks won't be created. Check return value of xTaskCreate functions.
When I run into this problem, it's usually been that my interrupt vectors weren't pointing to appropriate handlers. So when the RTOS needed to do a context switch, for example, it jumped off into la-la land. Since you say that taking out the tasks allows it to run to the library call, but fails in the same way, it is possible none of your handlers are setup correctly.
The FreeRTOS website has an FAQ about getting new projects to run that I would suggest reading through to help troubleshoot this kind of problem:
https://www.freertos.org/FAQHelp.html#faq
You might also look at some of the other AVR examples included with FreeRTOS to see how they have interrupts setup: https://www.freertos.org/a00090.html#ATMEL
I´m facing a problem with an application in Arduino Uno.
The board has a sensor that its counting products every second, after some time it sends the number of products to the server however this process takes more than a second, so the code that it is registering the products is not called until this process is completed so a piece of product sometimes is not counted.
I´ve been looking if Arduino supports multi-threading in order to have a thread for sending data to the server and the other one for registering the number of products, but i have no clear answer so far.
What would be the best solution to face this problem?
const long MAX_ITERATION = 100000;
const int OFF = 1;
const int ON = 0;
const int PHOTOELECTRIC_SENSOR = 3;
int counter = 0;
long iteration = 0;
int state = OFF;
void loop() {
registerProduct();
if (iteration >= MAX_ITERATION) {
// this process takes more than a second
sendDataToServer();
iteration = 0;
}
iteration++;
}
void registerProduct() {
int currentSensorState = digitalRead(PHOTOELECTRIC_SENSOR);
if (currentSensorState != state) {
if (currentSensorState == ON) {
counter++;
}
}
state = currentSensorState;
}
void sendDataToServer() {
// Sends data through HTTP protocol, and sets counter to zero
}
It looks like you might want to redesign this. While you might want to use something like threading on a desktop platform you don't have any hardware support for concurrency in that manner on the Arduino UNO. You do however have interrupts which you can use for your current problem.
Put the sensor on a pin change interrupt. Increment the counter in the ISR for that pin change interrupt. Arduino UNO has a few general purpose pin change interrupts, look at the datasheet for more info.
Then create a timer by using one of the internal timers. Attach this to an interrupt, when the timer interrupt fires take the counter amount and then put this aside. You will need to then send that value over to the server. Try to make the send not block. You may need to service the send in the main loop over multiple loop cycles.
By using the interrupts, especially the timing ones, you will free up a lot of processor cycles. Try to keep the amount of code in each of the ISRs as minimal as possible so that you don't lose data from interrupts being missed.
There is no concurrency in the microcontroller hardware or the language.
The correct way to do this is use an interrupt to accept the updates form the sensor asynchronously.
You should also not block on the send, you should send a few bytes and then send a few more on every loop through.
Using interrupts would be the preferred method, but you can also get away with using a simple or timed scheduler.
I've been working on a project that required one a while ago and you can find the source code here. It's based on a more extensive queuing library by Zuph called AVRQueue.
A simple implementation of the Scheduler library. I originally wrote it to be compiled with an avr-c compiler and haven't testing it with the arduino IDE but it shouldn't be an issue.
Scheduler m();
void setup() {
m.addTask(querySensor, "q_sens", 0, 1000);
m.addTask(doStuffWithData, "stuff", 0, 5000);
}
void loop() {
m.run(millis());
}
int querySensor(unsigned long now) {
...
}
int doStuffWithData(unsigned long now) {
...
}
I've researched a bit, and I've ran into a couple of examples of how buttons are used as interrupts. However, the design I'm trying to implement uses analog sensors. Right now, what I want to do is to have my analog sensors flag a boolean to tell the interrupt to execute, not a button. How would I do so?
This is what I have thought up based on what I researched:
boolean isWall;
attachInterrupt(isWall, interruptFunction, RISING);
void loop() {
if(analogSensor.response > 450) {
isWall = true;
}
normalExecution(); // what it normally does if isWall is false
}
void interruptFunction() {
// code implementation
isWall = false; // set isWall back to false after executing interruptFunction
}
void normalExecution() {
// foo
}
Can someone verify?
Perhaps I am completely wrong but it has always been my understanding that interrupts in Arduino are based on the voltage seen by a pin - i.e. they are hardware interrupts. Consequently, while your code is correct for a hardware interrupt, it will not work for a change in a variable.
That said, this link and this link discuss Analog Comparator methods for accomplishing what you are trying to do.