I am working on a school project for which I rotate a servo after a cable disconnects and a specific delay is over. This is my current code. We are using an Arduino Uno powered from the USB port
#include <Servo.h>
int reader=4;
int servo1Pin=8;
Servo servo1;
int value;
int pos=10;
int wacht=5000;
void setup() {
pinMode(reader, INPUT);
servo1.attach(servo1Pin);
}
void loop() {
value = digitalRead(reader);
servo1.write(pos);
if (value == LOW) {
delay(wacht);
pos=180;
}
else {
pos=10;
}
}
wacht is the specific delay. When we disconnected pin 4 to break that circuit we don't have a consistent time between the interruption of the power flow and the opening of the servo. It seems to vary from anywhere between 5 to 40 seconds of delay after triggering. Does anyone have any ideas to solve this issue?
try change
pinMode(reader, INPUT);
to
pinMode(reader, INPUT_PULLUP);
And for clarification delay don't use timer.
The order of your instructions seem strange. the usual order is:
Read
Decide
Act
Also, you may want to avoid sending useless instructions to the servo. For example, when you know the servo is already in the correct position. You should not rely on eternal code to do the right thing. In other terms, you have no idea how long servo1.write() takes to execute.
Which would give for your loop()
void loop()
{
if (digitalRead(reader) == LOW)
{
if (pos != 180)
{
delay(wacht); // delay() is only called once, when circuit breaks.
// this guarantees immediate response when circuit
∕/ closes again.
pos = 180;
servo1.write(pos);
}
}
else if (pos != 10)
{
pos = 10;
servo1.write(pos);
}
}
Also, have a look and implement Peter Plesník's answer. This will probably solve some of your problems. You input will definitely still have a random lag of up to 5 seconds when closing the circuit, though.
Related
i am trying to make a stopwatch and counter project for arduino. Code aside, is this wired correctly?
The top button is to start the stopwatch, second is the button to start the counter (every press increases by one), and the bottom button should be to reset any of them. the green light is to show the stopwatch is selected and blue is to show the counter is selected. the lcd is to display everything obviusly. Also, what is the best way to learn to code this and how long would it take? Thanks.
This is the code as per your requirement. I have defined pins as per above connections. counter mode has minutes and seconds and it does not contain milliseconds as I am encountering problem to implement it. You can suggest me if you have got any way. Counter mode selection button is the same button which is going to be used to increment the counter.
#include <LiquidCrystal.h>
LiquidCrystal mylcd(7,6,5,4,3,2);
int counter_sel=12,stopwatch_sel=11,reset1=10,stopwatch_led=9,counter_led=8;
void setup()
{
mylcd.begin(16,2);
mylcd.setCursor(0,0);
mylcd.print("Counter and ");
mylcd.print("Stopwatch");
delay(1000);
pinMode(counter_sel,INPUT);
pinMode(stopwatch_sel, INPUT);
pinMode(reset1, INPUT);
pinMode(counter_led,OUTPUT);
pinMode(stopwatch_led, OUTPUT);
}
void loop()
{ int state1=digitalRead(counter_sel);
int state2=digitalRead(stopwatch_sel);
if (state1==0) {delay(300); counter(); } // call counter function
else if (state2==0) {delay(300); stopwatch(); } // call stopwatch function
}
void counter()
{ mylcd.clear();
digitalWrite(counter_led,1);
mylcd.setCursor(0,0);
mylcd.print("Counter Mode :");
short int i=0;
while(1)
{
int rst=digitalRead(reset1);
if (rst==0) { delay(300); break;}
int state1=digitalRead(counter_sel);
if (state1==0) { i++; delay(200);}
mylcd.setCursor(0,1);
mylcd.print(i);
}
digitalWrite(counter_led,0);
}
void stopwatch()
{
mylcd.clear();
digitalWrite(stopwatch_led,1);
long int ms=millis();
byte sec=0, mins=0;
mylcd.setCursor(0,0);
mylcd.print("Stopwatch Mode : ");
while(1)
{
mylcd.setCursor(0,1);
int state1=digitalRead(reset1);
if (state1==0){delay(300); break; }
if (sec==59) {mins++; sec=0;}
if ((millis()-ms)>1000) {sec++; ms=millis(); }
mylcd.print(mins);
mylcd.setCursor(3,1);
mylcd.print(":");
mylcd.setCursor(5,1);
mylcd.print(sec);
mylcd.print(":");
//mylcd.print(millis()-ms);
}
digitalWrite(stopwatch_led,0);
}
As much as I can see, and considering what you explained above, the connections are correct. But the thing is you need to make it clear as much as you can, because due to intersecting point in LCD connection, it would be very much harder to debug and resolve the connection problem, for that you must make it neat. To learn to code this stuff there is no rocket science, just use your wisdom, and start reading books, blogs, articles on arduino ide(which is too simple too use), c programming and microcontrollers , and youtube videos are the great source to learn to code, you should have handful experience of c programming, that's all.
I need to check if a LED is blinking every 2 seconds...is it possible? I am using Arduino Mega 2560. Thank you.
There are multiple options, depending on the LED itself.
If you have access to the wiring of the LED (I assume 5V !) you can connect a interrupt Pin of the Arduino with it and a common GND. Now you can count the "Turn Ons" and devide it by the Time, to get an average value, which should be equal to two.
Example Code would be (NOT tested!):
#define MEASUREPIN 2 // Watch https://www.arduino.cc/en/Reference/AttachInterrupt for infos
long measureStartTime{0}; // ms since start of first blink
long runTime{0}; // [ms]
long avgTime; // [ms]
volatile long cycles{0};
void setup() {
pinMode(MEASUREPIN, INPUT);
Serial.begin(9600);
attachInterrupt(digitalPinToInterrupt(MEASUREPIN), countCycles, RISING);
}
void loop() {
if(measureStartTime == 0 && cycles == 0){
Serial.println("Blink not started");
}else{
if(measureStartTime == 0){
measureStartTime == millis();
}else{
runTime = millis()-measureStartTime;
avgTime = runTime/cycles;
Serial.print("Average blink interval: ");
Serial.print(avgTime);
Serial.println("ms");
}
}
}
void countCycles(){
cycles++;
}
If you haven't access to the wiring you can use a lightsensor, to generate a similar signal.
I hope that fits your needs, because i am not allowed to comment, so i couldn't get further infos.
I am using an Arduino Uno, connected to a USB shield, a RFID shield(adafruit PN532), an LCD, EEPROM(24AA256) and a RTC module(DS1307). I will not post my code here because it is too large and it is separated in multiple files.
In my program, I realize that if my programs enters a certain functions, after entering function after function, if I use a delay() at the end of the function I am currently in, the arduino resets. An example of what I mean is below.
void a() { b(); }
void b() { c(); }
void c() { d(); }
void d()
{
lcd_string("Testing", 0x80);
delay(2000); <---- Arduino resets at the delay here
}
At first, I thought it was because my dynamic memory was at 80%, and when I compiled, they said the Arduino might have some stability issues. So I modified my code such that my dynamic memory is now 57%. Problem still exist.
I thought maybe the delay() function has some overflow or something, so I tried replacing the delay with the following code.
unsigned long timing;
timing = millis();
timing += 2000;
while(millis() < timing);
The Arduino still resets.
Next, I thought maybe because my arduino is connected to my PC, some serial pin might have been causing the reset, so I used an external Power to power up the arduino and disconnected the USB. The arduino still resets.
Next, I thought maybe Timer1 might have been crashing with the delay() function, although the delay function uses Timer0 so I disabled my Timer1 . The arduino still resets.
Is there any other possibilities that I am missing out? My program storage space is at 69% which I believe shouldn't be an issue.
Edit
Here is my code for Timer1 ISR
ISR(TIMER1_OVF_vect)
{
TCCR1A = 0;
TCCR1B = 0;
TCNT1 = 0;
OCR1A = 34286;// = (16*10^6) / (1*1024) - 1 (must be <65536)
TCCR1B |= (1 << CS12);
// enable timer compare interrupt
TIMSK1 |= (1 << TOIE1);
triggered = 1;
}
Any other interrupt of flags used are in the library header files.
I am using the following external libraries
USB Host shield library 2.0
Adafruit PN532 master
A little sample to come close to RAM corruption ...
#define MEM_PER_LEVEL 50
#define TRY_TO_SURVIVE 10
void KillMe(int level) {
byte dummy[MEM_PER_LEVEL];
for ( byte i = 0; i < MEM_PER_LEVEL; i++)
dummy[i]= i;
Serial.println(level);
delay(1000); // not sure why this would hurt more than others
if (level < TRY_TO_SURVIVE) KillMe(level+1);
for ( byte i = 0; i < MEM_PER_LEVEL; i++) {
if (dummy[i] != i) {
Serial.println(F("corruption happened"));
while(1) {} // HALT
}
}
if (level == 0)
Serial.println(F("survived"));
}
void setup() {
Serial.begin(9600);
KillMe(0);
}
void loop() { }
I had the same problem - wherever I put a delay in my setup function the Arduino would restart.
For me, the problem was an instance of SoftwareSerial with invalid pin numbers.
SoftwareSerial mySerial(30, 31);
Anyone else landing on this question should check their pin numbers are appropriate for the board they're targeting. Not sure why the crash only happens if a delay is called, would be interested if anyone has insight into this!
I need help with debounce of push button. Sometimes it send twice same string to serial link, and I don't know why. Could someone help me, where is a problem?
int reading;
int exbutton= LOW;
unsigned long ddelay= 200;
unsigned long last= 0;
void loop(){
reading= digitalRead(prkgbrake);
if (reading== HIGH && exbutton == LOW && millis() - last> ddelay){
if (brake == 0){
Serial.write("brake:1\n");
while( digitalRead(prkgbrake) == HIGH){
}
}
else{
Serial.write("brake:0\n");
while( digitalRead(prkgbrake) == HIGH){
}
}
last = millis();
}
Thank you in advance.
I hope you didn't copy this code from somewhere, some of the code doesn't make sense.
For instance, what is 'prkgbrake'? What is 'brake'? They are not declared. Why don't you have a 'setup()' function?
Nevertheless, debouncing can be achieved in many ways. I will just fix your code. That way you will understand what you did wrong.
int exbutton = LOW;
unsigned int _delay = 200;
int pushButton = 2;
void setup()
{
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
pinMode(pushButton, INPUT_PULLUP);
}
void loop()
{
while (digitalRead(pushButton) == LOW && exbutton == LOW)
{
if((millis() - last) > _delay)
{
Serial.println("Button Pressed");
while(digitalRead(pushButton) == LOW);
}
}
last = millis();
}
Explanantion: Assuming your pushbutton is connected with digital pin 2. When you use a digital pin with a button it is better to use pullup/pulldown. You can use external resistor or the internal resistor for that. The internal resistor only supports Pull-up.
To know more about pull-up/-down checkout this Arduino page. The bottom line is when you use a pin as input it acts like an antenna and can capture signals from surroundings, known as floating state. So it is better to keep the pin in a known state. If you use internal pull-up, the pin will be always HIGH. So the button configuration has to be in a way so that when it is pressed the pin should go LOW.
Pull Up Configuration
The code pinMode(pushButton, INPUT_PULLUP); enables the digital pin 2 as input with pull-up enabled.
the loop() should work like this:
1) Check if the button is pressed (i.e. if it is LOW).
2) If not update the last variable.
3) If yes then DONT update last, and enter the while loop.
4) Now keep checking if millis()-last is greater than _delay. If not it will go back to while loop and check if the button is still pressed or not. If yes then it will come back and check if millis()-last is more than _delay or not. It will continue to do so until it passed the mentioned amount of debounce delay.
5) If button get depressed (i.e. goes to HIGH) before the '_delay' time then it will update the last and will check if button is pressed or not and will start counting the delay time.
N.B. Play with the _delay variable. It will define the responsiveness of your button.
I need help with an Arduino sketch , I want to repeat the blink sketch for a specified amount of time (3minutes for example) , then Stop .As we know , the loop() keeps runing forever which is not what I want . Any ideas how I can achieve this , blinking an LED for X minutes and Stopping ?
You should probably make use of some timer library. A simple (maybe naive) way to achieve what you want to do is to make use of a boolean that is set to 0 when 3 minutes has passed or simply digitalWrite the led to low when the timer has passed.
Check this link:
http://playground.arduino.cc/Code/Timer
I suggest that you use int after(long duration, callback).
Below is a (very) simple example of how you probably could do:
#include "Timer.h"
Timer t;
LED = 1;
void setup() {
int afterTime = t.after(180000, cancelLED);
}
void loop() {
t.update();
if(LED) {
//The "write HIGH" statement in your sketch here.
}
else {
//Write the led to LOW
}
}
void cancelLED() {
LED = 0;
}
I haven't used the library myself, I just checked the the docs and wrote an example to give you some ideas. Don't expect it to work right away.