The CDS sensor module connected to the Arduino Nano returns only a value of 1023.
my code hear
int Cds = A0;
//int Led = 13;
int value;
void setup() {`enter code here`
Serial.begin(9600);
pinMode(Cds,INPUT);
//pinMode(Led,OUTPUT);
}
void loop() {
Cds=analogRead(A0);
Serial.println(Cds);
if(Cds<300)
Serial.println("dark");
else
Serial.println("bright");
delay(1000);
}
and nano is connected breadboard
Check analogReference() in the code for your board to configures the reference voltage used for analog input. If you have have correct reference voltage setup you get 1023 max value all the time.
Firstly, the first line in loop() should be changed to:
value = analogRead(Cds)
And from there, just use value for accessing the brightness, because Cds is just your alias for A0
The second possible Error source could be this:
If you just connect the module to GPIO and GND, nothing will happen, and it will always read the maximum value (1023).
You need to use it like a voltage divider, to read values which are relative to a certain voltage
If you connect everything like this, it should work.
Related
Following this tutorial:
Arduino LED Dimmer Example
I added the Serial.println(brightness); at the bottom to see what gets written to the brightness variable and only get back 48 no matter the value sent by serial to the arduino.
As you can see the value of brightness goes from 50 to 48 where it settles. The sent data is in pink and the black data is the response from the arduino.
What else could I try.
Thanks
Using the Hercules utility to establish a serial link to the arduino.
Hercules Utility Showing communication with Arduino
The oscilloscope sees this:
PWM signal from oscilloscope
const int ledPin = 9; // the pin that the LED is attached to
void setup() {
// initialize the serial communication:
Serial.begin(9600);
// initialize the ledPin as an output:
pinMode(ledPin, OUTPUT);
}
void loop() {
byte brightness;
// check if data has been sent from the computer:
if (Serial.available()) {
// read the most recent byte (which will be from 0 to 255):
brightness = Serial.read();
// set the brightness of the LED:
analogWrite(ledPin, brightness);
Serial.println(brightness);
}
}
your problem is obvious in the image you provided , for example in the image it shows
when send 100 , the arduino responded with 49 , 48 , 48 which is the ascii representation of the 100 , refer to ascii table where
'1' is equivalent to 49
'0' is equivalent to 48
which means that you send to the arduino the number 100 not as a number but as a string where your terminal sends 1 first in its ascii representation which is 49 then it sends 0 in its ascii representation which is 48 then it sends another 0 in its ascii representation which is 48.
to solve this problem:
in your pc side , try to change that in your terminal settings
or
in your arduino code , instead of brightness = Serial.read(); write brightness = Serial.parseInt(); , refer to Serial.parseInt() docs where it says that :
Looks for the next valid integer in the incoming serial. The function terminates if it times out
meaning that it will convert "100" (string) into 100 (number) in your arduino side .
also change byte brightness; into int brightness; as Serial.parseInt() returns the next valid int
Thank you abdo salm, your suggestion educated me and resolved my problem at the same time. Answer updated for anyone who stumbles across the same rookie issue (see snippet below).
So in conclusion, the example code expected a number in the range of
00000000 to 11111111 (0 to 255 as a single binary byte)
I was instead sending multiple bytes that represented One, Zero and Zero on the ASCII table
11000100 (49)
11000000 (48)
11000000 (48)
erroneously thinking I was sending 100 which is 110010000 in binary.
I altered the code with brightness = Serial.parseInt(); as abdo salm suggested.
Here is the Hercules (or similar) friendly version of the Arduino Dimmer Example.
const int ledPin = 9; // the pin that the LED is attached to
int brightness;
void setup() {
// initialize the serial communication:
Serial.begin(9600);
// initialize the ledPin as an output:
pinMode(ledPin, OUTPUT);
}
void loop() {
// check if data has been sent from the computer:
if (Serial.available()) {
// read the most recent byte (which will be from 0 to 255):
brightness = Serial.parseInt();
// set the brightness of the LED:
analogWrite(ledPin, brightness);
Serial.println(brightness);
}
}
Hi I am attempting to read from an rc transmitter using an Arduino Uno board, I have a signal pin connected from the receiver to pin 9 on the Arduino. Here is the code I would really appreciate some help all I am trying to achieve is the read the pmw from the receiver. I am able to plug a servo into the receiver and that works fine along with a motor I am just struggling when I try and use the Arduino with the receiver. When I run my program all I get in the Serial monitor are values such as 9991,9972,10030,10050 that are completely unrelated.
I want to have a pmw value that I can map to 0-255 in order to control a motor
My Circuit:
battery -> ESC(for BEC to regulate five volts back to receiver)-> receiver -> ch3 signal pin -> Arduino uno (pin9)
void setup() {
Serial.begin(9600);
}
void loop() {
int pwm = pulseIn(9, HIGH, 25000);
Serial.println(pwm);
delay (5);
}
You are using pulseIn which returns a time (in ms). The time being how long it waited for a HIGH signal. If you want the actual value, use analogRead. You can still use pulseIn, just don't use the return value
void setup() {
Serial.begin(9600);
}
void loop() {
byte pwm = analogRead(A5) / 4;
Serial.println(pwm);
delay(5);
}
I am trying to retrieve data from an RLS absolute rotary encoder via SPI through Arduino Uno. I have managed to learn the basics of SPI, but I can't seem to get this working. I keep printing the transfer data and keep getting 255.
I also use the recommended pins for Arduino Uno here: https://www.arduino.cc/en/reference/SPI
Here is the link to the Absolute Encoder DataSheet: https://resources.renishaw.com/en/details/data-sheet-orbis-true-absolute-rotary-encoder--97180
Any help is appreciated.
Here is my code I have been trying:
#include <SPI.h>
unsigned int data;
int CS = 10; //Slave Select Pin
// The SS pin starts communication when pulled low and stops when high
void setup() {
Serial.begin(9600);
RTC_init();
}
int RTC_init() {
pinMode(CS, OUTPUT);
SPI.begin();
SPI.setBitOrder(LSBFIRST); // Sets Bit order according to data sheet (LSBFIRST)
SPI.setDataMode(SPI_MODE2); // 2 or 3, Not sure (I have tried both)
digitalWrite(CS, LOW); // Start communications
/*
Commands List:
Command "1" (0x31) – position request (total: 3 bytes) + 4 for multi-turn
Command "3" (0x33) – short position request (total: 2 bytes) + 4 for multi-turn
Command "d" (0x64) – position request + detailed status (total: 4 bytes) + 4 for multi-turn
Command "t" (0x74) – position request + temperature (total: 5 bytes) + 4 for multi-turn
Command "v" (0x76) – serial number (total: 7 bytes)
*/
unsigned int data = SPI.transfer(0x33); // Data
digitalWrite(CS, HIGH); // End communications
return(data);
}
void loop() {
Serial.println(RTC_init());
}
First, you forgot to set your CS pin to output. That won't help.
void setup()
{
Serial.begin(9600);
digitalWrite(CS, HIGH); // set CS pin HIGH
pinMode(CS, OUTPUT); // then enable output.
}
SPI is a two way master/slave synchronous link, with the clock being driven by bytes being sent out by the master. This means that when transacting on SPI, you are expected to send out as many bytes as you want to receive.
As shown on the timing diagram on page 14 of the datasheet, you are expected to send one byte with the command, then as many null bytes as the response requires minus 1.
The diagram shows the clock being low at idle, and input bits being stable when the clock goes low, that's SPI mode 1.
To read the position, for a non-multiturn encoder.
unsigned int readEncoderPos()
{
// this initialization could be moved to setup(), if you do not use
// the SPI to communicate with another peripheral.
// Setting speed to 1MHz, but the encoder can probably do better
// than that. When having communication issues, start slow, then set
// final speed when everything works.
SPI.beginTransaction(SPISettings(1'000'000, MSBFIRST, SPI_MODE1));
digitalWrite(CS, LOW);
// wait at least 2.5us, as per datasheet.
delayMicroseconds(3);
unsigned int reading = SPI.transfer16(0x3300); // 0x3300, since we're sending MSB first.
digitalWrite(CS, HIGH);
// not needed if you moved SPI.beginTransaction() to setup.
SPI.endTransaction();
// shift out the 2 status bits
return reading >> 2;
}
I am trying to program some software for my Arduino to read data from an IR fire detector module, I know the module works but I just cannot get the Arduino to read from it and carry out a function correctly. I want it to work like this...
const int IRDetector1Input = A2;
const int IRDetector1Output = A1;
const int LEDButton = 3;
void setup(){
pinMode(IRDetector1Input, INPUT);
pinMode(IRDetector1Output, OUTPUT);
pinMode(LEDButton, OUTPUT);
void loop(){ //Problem Point
if analogRead(IRDetectorInput, HIGH); //This is the problem, the code doesn't match with digital or analog write.
digitalWrite(LEDButton, HIGH);
There are a couple of issues that I see.
One, is that you are using the analogRead() function incorrectly. When you perform an analogRead() the function reads a digital representation of the voltage as seen at the requested pin and returns an integer value (0 to 1023). Also, this function only takes a single parameter, the pin number. You are sending the pin number and HIGH. Here is an example of what to do if you wanted to know what the digital representation of the voltage was at that analog pin:
int analogValue;
analogValue = analogRead(IRDetector1Input);
The second issue is with your if() statement. I believe that you are trying to see if the value received at the pin (where your IR detector is connected) is actually HIGH. First, your if() statement would be more correct (but still wrong), like this:
if (analogRead(IRDetector1Input) == HIGH)
digitalWrite(LEDButton, HIGH);
The reason that it is still wrong is that HIGH is a value that is defined as being the integer number 1, whereas LOW is defined as 0. So, you would be comparing the return value of analogRead() which could be anywhere from 0 to 1023, to the number 1.
So... how can you fix it? Well, it's tough to say without knowing how your IR detector module works. If the detector sends a digital value (a high voltage or a low voltage and not something in between) to your Arduino, use digital functions and a digital pin (i.e. digitalRead()). However, if your IR is actually sending an undetermined voltage, then set an analog threshold and check for it. You will need to run tests to determine where this threshold should be. For example:
#define ANALOG_IR_THRESHOLD 750 /* Arbitrarily set */
if (analogRead(IRDetector1Input) >= ANALOG_IR_THRESHOLD)
{
digitalWrite(LEDButton, HIGH);
}
So my problem is as title says: Arduino UNO analogRead always returns 1023.
But when I burn the same sketch in Arduino Mega 2650 everything works like a charm.
I have tried to change Atmel chips on the UNO, have tried like 3 of them (ATMEGA328P-PU) and nothing changes.
I'm trying to count signals from a hall effect sensor and display the count on a 7 segment display.
Here is the code:
#include "SevSeg.h"
SevSeg sevseg;
volatile int rpmcount;
void setup() {
Serial.begin(9600);
pinMode(2,INPUT_PULLUP);
rpmcount = 0;
sevseg.Begin(1,3,4,5,6,7,8,9,10,11,12,13);
}
int border=15;
void loop() {
int tmp=0;
tmp = analogRead(0);
if(!digitalRead(2))rpmcount=0;
Serial.println(tmp,DEC);
if(tmp<=border && res >border){
rpmcount++;
if(rpmcount>9999)rpmcount=0;
}
res=tmp;
sevseg.NewNum(rpmcount,(byte) 0);
sevseg.PrintOutput();
}
Any help would be much appreciated
This sounds to me as if you had the internal pullup resistor on the ADC pin enabled.
generic checklist:
ACD bit in ACSR is 0 (comparator enable)
MUX bits in ADMUX set properly
correct AREF selected
ADC pin set as input
internal pull up resistors are deselected