Hello,
I am using humidity and temparature sensors and controlling relays with datas which i got from them. But my all my LCD screen flickering. Can i prevent it with a common solution or do i review codes line by line ? By the way i couldn't share my codes due to the project's privacy policy.
Thank you.
We don't need to see the code from your project but it would be helpful to see some code that reproduces the problem.
The title (and ONLY the title) claims that the flickering is due to the millis() function. This is unlikely unless your code is abusing the millis() function. What makes you think that the millis() function is causing your LCD to flicker?
vaj4088:
We don't need to see the code from your project but it would be helpful to see some code that reproduces the problem.The title (and ONLY the title) claims that the flickering is due to the millis() function. This is unlikely unless your code is abusing the millis() function. What makes you think that the millis() function is causing your LCD to flicker?
When i delete the millis() the LCD flickering is stopped.
Thank you.
EGUVEN:
By the way i couldn't share my codes due to the project's privacy policy.
Then, it seems like you have two choices:
gfvalvo:
Then, it seems like you have two choices:
- Pay someone to fix your problem after they sign an NDA.
- Create an MCVE that you can post and demonstrates the problem.
Yes, hiring a freelancer for it will be my last step but before to do it i want to know if i could do something.
EGUVEN:
Yes, hiring a freelancer for it will be my last step but before to do it i want to know if i could do something.
That would be option #2 write a code demonstrating the problem that you can post. Perhaps someone reading here in the forum could suggest a solution.
A flickering LCD display is often caused by clearing the display then having a short delay before writing new information to the display. The problem is made worse by updating the display unnecessarily, when there is no change in what is displayed. For something like a temperature/humidity display, the common solution is to only update the display when the temperature or humidity changes, and then do not clear the entire display, but instead position the cursor at the proper location and overwrite only the temperature or humidity, as applicable.
david_2018:
A flickering LCD display is often caused by clearing the display then having a short delay before writing new information to the display. The problem is made worse by updating the display unnecessarily, when there is no change in what is displayed. For something like a temperature/humidity display, the common solution is to only update the display when the temperature or humidity changes, and then do not clear the entire display, but instead position the cursor at the proper location and overwrite only the temperature or humidity, as applicable.
With this perspective i searched lcd.clear and lcd.begin .Deleting just 2 of them solved my problem 
it's working realy good now :). I think the "common solution" way of problems to direct developers right direction. Thank you.
I guess you putted a lcd.clear() function in the beginning of your loop, instead, put the lcd.clear() right before lcd.print(), this way the gap between clearing the display and writing new info on it will disappear.
instead of this:
lcd.clear();
//code
//code
//code
//code
//code
lcd.print("somthing");
Do this:
//code
//code
//code
lcd.clear();
lcd.print("somthing");
//code
//code
//code
Setrik_aZ:
I guess you putted a lcd.clear() function in the beginning of your loop, instead, put the lcd.clear() right before lcd.print(), this way the gap between clearing the display and writing new info on it will disappear.
You can still get a noticeable flicker if the majority of the screen stays the same. When you are displaying something where most of the screen is a fixed image or text, and only a small portion changes, it is much better to overwrite only what changes.
david_2018:
You can still get a noticeable flicker if the majority of the screen stays the same. When you are displaying something where most of the screen is a fixed image or text, and only a small portion changes, it is much better to overwrite only what changes.
Usually I design my LCD pages to be like several menus, but in both menu pages and normal pages (like showing all the info on one single screen), I put all the LCD related codes ( lcd.write , clear, print etc...) at the very end lines of the sketch (as much as possible).
I used to have the same flickering problem but after I found this methods I don't have any issues with flickering anymore.
But I suggest to write a one single line of code in an sketch with no delay to see if anything is wrong with the LCD itself or not.
It is good practice to write to the display only when the value to be displayed changes and even then to only write the new value to the display rather than clearing it and writing everything again
EGUVEN:
With this perspective i searched lcd.clear and lcd.begin .Deleting just 2 of them solved my problem
I'm glad that you found a solution that way, but rarely is that the case. You just got lucky. You have to mentally reverse the roles and read your question as if it were someone else's question, and consider the infinite range of causes that might lie behind a generally expressed issue. Especially, because there are many novice coders here, and only occasionally wave a big sign that says, "new experimenter". If you hang out here for a while and read many questions, you will discover that the norm is that most people consistently overestimate the quality of information that they post, to describe the problem.
UKHeliBob:
It is good practice to write to the display only when the value to be displayed changes and even then to only write the new value to the display rather than clearing it and writing everything again
Can you explain how to write only one thing on the screen? is there a way to clear just a few segments of the LCD?
for example, you have this written on your screen:
Temp: 26°C
then the temperature drops to 8°C, if you print the new value on top of the last value you'll get this:
Temp: 86°C
the last thing written on the screen wont be cleared, how can you fix that without clearing the whole screen and writing everything again?
I would say, instead of using lcd.clear() function, use lcd.print() with needed number of white spaces,
for example, in the problem I said, you need to clear segments [7,0], [8,0], [9,0] and [10,0] before printing the new value,
I would do this:
lcd.setCursur(7,0);
lcd.print(" "); //4 spaces
lcd.setCursur(0,0);
lcd.print("Temp: ");
lcd.print(value);
lcd.print("°C");
Is this the right way to do it or is there any more standard way?
Can you explain how to write only one thing on the screen? is there a way to clear just a few segments of the LCD?
Print the text just once in setup()
Position the cursor to where you want to print the value
Print enough spaces to erase the previous value
Position the cursor to where you want to print the value
Print the value
Note that you only print the text once, not every time the temperature changes. You are only printing it when it changes, I hope
UKHeliBob:
Print the text just once in setup()
Position the cursor to where you want to print the value
Print enough spaces to erase the previous value
Position the cursor to where you want to print the value
Print the value
Is some cases, you can also:
Position the cursor to where you want to print the value.
Print the value.
Print enough spaces to pad out the field.
EGUVEN:
I am using humidity and temparature sensors and controlling relays with datas which i got from them. But my all my LCD screen flickering. Can i prevent it with a common solution or do i review codes line by line ? By the way i couldn't share my codes due to the project's privacy policy.
Aren't LCDs supposed to flicker?