I am using an Arduino Mega with a 16x2 LCD. When I start the Arduino the LCD flashes white and sometimes random lines will show up and gradually fade out. The backlight is on, however, so the LCD is not inverted. At first I thought the Arduino was not getting enough power because I am using a Raspberry Pi to program it, but plugging in a 6V battery pack did not change the result. I tried plugging in a different 16x2 LCD to check if the one I was using is broken, but again, the result was the same. I have triple-checked my connections, adjusted the potentiometer, and fiddled around with where the LCD was connected on the breadboard in case some of the pins were broken, but to no avail.
Does the LCD have a problem with Arduino Mega boards? Or am I just unfortunate enough to have two broken LCDs?
Code:
#include <LiquidCrystal.h>
#define led_pin 22
#define buzzer_pin 7
LiquidCrystal lcd(12,11,5,4,3,2);
void setup() {
pinMode(led_pin, OUTPUT);
pinMode(buzzer_pin, OUTPUT);
lcd.begin(16,2);
digitalWrite(led_pin, HIGH);
tone(buzzer_pin, 1000, 500);
delay(500);
digitalWrite(led_pin, LOW);
lcd.print("LCD Test");
}
void loop() {
}
EDIT
I moved the LCD and wiring back to the other side of the breadboard and it did not change the output. I'm starting the think that the LCDs are just simply broken because the LCDs will randomly flash and fade unevenly. I found that these LCDs can be easily fried by incorrectly adjusting the potentiometer.
Make sure that you solder headers to the lcd, then press the headers into your breadboard and connect to arduino with jumper wires. Just resting the LCD on the headers without solder or jabbing the lcd pin holes with jumper wires don't make reliable connections. You WILL see random stuff
Make sure you connect the LCD correctly. If you did, you wouldn't have got any problems. Post a picture.
Make sure the pins you used in the code match pins you connected to the LCD.
Best way to get arduino help is on arduino forum.
Specifically which LCD are you using?
Do you have datasheets for the exact LCD you are using so you can confirm you have the correct wiring and supply voltages?
If you still have no luck, you may want to try a LCD module that has a serial, i2c, or spi interface.
They are much easier to use than HD44780 parallel modules (im assuming this is what you have).
An example source of such modules is https://www.crystalfontz.com/c/character-lcd-displays/interface/24
Related
I want to program Stm32 bluepill with Arduino IDE but when I want to define pins like I write " pinMode(A10, OUTPUT)" it gives error. the error is "'A10' was not declared in this scope"
I want to know how should I declare Pins in Arduino IDE for STM32
Based on the error you're reporting, you're not building your code for the correct board. I suspect you're targeting the ArduinoUNO (default) which does not have an A10.
Also, as hcheung's answer mentions, the name on the blue pill is "PA10".
Follow the instructions here to install the board configuration for the STM "blue pill" then select it and build again.
https://maker.pro/arduino/tutorial/how-to-program-the-stm32-blue-pill-with-arduino-ide
Note, the board selection as of today is now "STM32F1 series" instead of "STM32F103C series" as specified at the link.
One reason could be there is not ADC pin of number 10 for the currently selected board (check the board on tool -> boards), there might be fewer number of ADC pins, e.g. try A0.
Or maybe you have selected wrong board. Bluepill isn't included in the Arduino IDE, by default. So you have to add it to your IDE first.
There is a nice instruction here on how to do this and a sample code.
https://maker.pro/arduino/tutorial/how-to-program-the-stm32-blue-pill-with-arduino-ide
Remember that this newly installed library could have small differences in syntax compared with standard Arduino code, Like this example that is taken from the mentioned site:
void setup() {
// change pin PC13
pinMode(PC13, OUTPUT);
}
//infinite loop
void loop() {
digitalWrite(PC13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(PC13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
As you can see here the pin is selected using "PC13", and not just a number aka "13".
So in this case by installing the library used in the mentioned site you should write PA0 to PA7 for using ADC.
Here is a sample picture displaying the name of the pins and their features:
For STM32 Blue Pill with Arduino Core, digital pins are named based on its port and pin number, such as PB1, PA10.
There is no A10, I assumed that you mean PA10 (which was marked on the Blue Pill PCB as "A10" (for Port A Pin 10) due to limit space on the PCB.
To use it as a digital pin, simply use PA10 to address it, that is:
pinMode(PA10, OUTPUT);
or because PA10 internally happened to be referred as D10, you can also use:
pinMode(10, OUTPUT); //not recommended
For better understanding of all the pin assignments for STM32F103 Blue Pill, please take a look at the source code here and here.
I am new to electronics, and trying to get my 1602 LCD to work with an I2C adapter.
I got my backlight to work, but I can't get text to show.
This is my current code:
#include <LiquidCrystal_I2C.h>
#include <Wire.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
lcd.init();
lcd.backlight();
lcd.setCursor(5, 0);
lcd.print("HELLO");
}
void loop() {
lcd.backlight();
delay(2000);
lcd.noBacklight();
delay(2000);
}
I checked for the I2C address with the scanner and it is 0x27.
I Googled a bit and came past this post where someone posted this:
Simple test
Apply +5v / GND to LCD - display - and than apply background LED power ( sometime marked A/K) to the LCD module.
No other connections ( data etc.) are necessary for this power up test.
You should be able to discern ALL chatterers fields, but connecting contrast pot will make it easier.
It MAY not be totally visible but the module will initialize ( internally) on power up and ALL characters fields should show.
Of course by now you know you need basically three "power" connections to the LCD - LCD itself, contrast and backlight.
Sure looks as the main LCD power is missing - hence no intelligent data can be processed / displayed.
I did this test aswell and came to these results:
When providing 5V to the backlight, it shows up bright.
When providing 5V to both the backlight and the LCD itself the backlight gets darker but nothing else shows up.
I then accidentally put the I2C adapter upside down, but that did give me the text blocks.
How could I get the text to show? What am I currently doing wrong?
Minor point, have you tried trimming the pot? I suspect that this sets the contrast, and I forgot this and I had a blank display.
Yours Simon M.
Your I2C Adapter turns serial data into parallel output to the LCD pins.
Are you sure this is done to the pins you expect ?
Especially if you mix any I2C adapter to any 16 pin LCD module, you should check which signals you put where ...
If required, there are LiquidCrystal_I2C constructors where you can specify the LCD pins, if the default won't fit.
I am a beginner to ARDUINO. My connections i guess is fine. But LED does not blink. Green and Orange light is blinking on ARDUINO. Anode to pin 13 with 320K resistor and Cathode to ground
Code is as follows
const int LED=13;
void setup()
{
// put your setup code here, to run once:
pinMode(LED,OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
digitalWrite(LED,HIGH);
delay(1000);
digitalWrite(LED,LOW);
delay(1000);
}
Looks like you plugged one of the legs in ground and one in Another slot.
Check your connections and if it doesn't work, try using another led, and switching the polarities.
The problem here in that you haven't connected anything to pin 13!
Also, a 320K ohm resistor is a little overkill. Usualy, a 220 ohm resistor is enough.
Also, the flat side of the led is the negative side. It is more reliable then if you are following the pins size which isn't always constant.
You need a resistor even if using pin13.
The led in the shield has it's own resistor but if you plug your own you need a resistor.
Take a look at this post:
https://electronics.stackexchange.com/questions/66992/pin-13-do-i-need-a-resistor
hello you can try removing the 320K resistor and replacing it with 220 ohms resistor or directly connec t LED to pin 13 because the onboard resistor is on
I am running out of pins. I used the pin that I use in LCD as output for a LED however the led is not turning off its always even my code is like this
void setup() {
lcd.begin(20, 4);
pinMode(7 , OUTPUT);
digitalWrite(7, low);
}
Plug off the LCD for a while to see whether your led blinking program is correct.
Anyway, you can't use the same pin for different functions, it's good chance that they will
disturb each other (say, the led will flash silly when you send something to the LCD),
kick out each other (as we see it in your case).
I am using an arduino uno and I am trying to control a motor with two inputs which I found in a small car I used to have as a child.
I connected the first pin of the motor to the arduino ground and the second one to the VCC and the motor started turning.
However, when I write the following code the motor doesn't work.
void setup() {
pinMode(8,OUTPUT);
digitalWrite(8,HIGH);
}
void loop() {
}
(I have connected the first pin of the motor to the ground and the second one to pin 8 of arduino).
Does anybody know why that happens?
You can only get a certain amount of current from an Arduino output pin. In general, you can light an LED with a direct connection to an output pin, but motors require more current. A detailed discussion is here.
To control a device such as a motor which needs more current than the output pin can provide directly, you can use an external transistor. You can buy circuits that implement this idea, such as this Motor Shield for Arduino.
This is not how Arduino is supposed to work with power consuming stuff (like mhopeng said, you may use LED in such a scheme, but not something more consuming): a motor should be between GND and 5V and if you want to control it, you have to use a transistor connected to an output pin.
I had a similar question once, it may be of help, too. Also, it may be a good idea to ask further questions at arduino.SE.