12
votes
Accepted
16x2 LCD showing blocks under text
The row of white blocks is what you get before the screen's initialized. It's normal.
The shadow behind the characters is because you have the contrast turned up too high. Adjust it down a little.
- 106k
11
votes
Request for help condensing code and saving memory
You have a huge switch...case here to decide the name of the file that
should be played. This costs a lot of code space, but also data space,
because every single literal string in this portion of ...
- 45.1k
7
votes
Accepted
Hooking up LCD screens reclaimed from old camcorders to Arduino
This is likely a type of TTL LCD interface. But it is nearly impossible to describe more as there are so many variations both in hardware and in timing.
Likely a steady stream of Red Green & Blue ...
- 7,503
7
votes
Accepted
Implement two processes at the same time
Think of an Arduino as a circus clown spinning plates. It has to spend very little time on any one plate, and then it can keep a lot of plates spinning, moving quickly from one to the next.
That's how ...
- 5,752
6
votes
Print output on 16x2 LCD and Serial Monitor
If you are using clasical UNO, then pins 0 and 1 are Serial. Declaring lcd(1,... make LCD use the pin 1 too, so Serial is confused and garbled.
Use other pins for lcd and adjuct the wires acordingly.
- 1,466
6
votes
Accepted
Simple LCD countdown timer
instead of 9, it printed 90
No, it didn't: it printed “9”. However, it did not erase the previous
value before printing “9”. Before printing the 9, the LCD had:
┌────────────────┐
│time left │
│...
- 45.1k
6
votes
Accepted
Read serial with header and end marker
The short answer to your question is “yes, there is a way”. Multiple
ways actually. You could write a blocking function, which follows more
or less the logic of the example you show, blocking while ...
- 45.1k
6
votes
Accepted
lcd.createChar() only allows for 8 custom characters
These displays only allow up to 8 custom defined characters. The hardware just only has the character RAM for at most 8 characters. They will be mapped to char codes 0 to 7 and 8 to 15. The character ...
- 1,306
5
votes
How to show the º character in a LCD?
Some displays have different characters above 128. It is best to make your own character.
That is what @dannyf ment with "CGRAM". The custom characters are stored in CGRAM. There is no need to read ...
- 3,276
5
votes
Accepted
Flip text in LCD screen
It's not possible. The text is a simple ASCII character set that is encoded in ROM. It can't (other than a few user-defined characters) be changed. And being simple ASCII it doesn't support any ...
- 106k
5
votes
Accepted
I2C sensors not working when I connect to LCD 20X04
Welcome to Stack Exchange!
I can spot a few problems with the circuit. As @hcheung said, the I2C pull-up resistors should only be wired between SDA>3.3V and SCL>3.3V (in parallel), not in series ...
- 126
4
votes
Adding an LCD to Uno but not enough pins left
You are using 8 GPIO pins for your existing modules. That leaves 12 left for an LCD (assuming you aren't using the serial port).
An LCD can work from as few as 6 pins (4 data, E and RS) - WR can be ...
- 106k
4
votes
Accepted
Compatibility between shields
Its not just a question of the stackability of the shields and the clash of pins you also need to consider what the shields do.
Stacking the GSM shield under the LCD is going to restrict is tx/rx ...
- 5,652
4
votes
Hacking old car dvd monitors with arduino
I realize this is an ancient question, but just in case someone else has one of these things, I'll share what I know. I have one of these Sharp LCDs that I typically use as a monitor for a Commodore ...
- 41
4
votes
Accepted
Can I generate 5 sec delay within an interrupt program?
You don't need interrupts for any of that. Your main loop just needs to test the switch, eg.
void loop ()
{
if (digitalRead (button) == HIGH) // assuming LOW means pressed
return;
// ...
- 38.9k
4
votes
Accepted
Resistors on LCD - does a small difference matter?
No, it doesn't matter. That resistor is just for the backlight LEDs. The larger the resistor the dimmer the backlight will be. As @VE7JRO suggests, you can always put two 330Ω resistors in parallel, ...
- 106k
4
votes
Accepted
My brand new LCD screen doesn't display anything, even though there is no code errors?
Turns out that the diagram was wrong. Needed to move the potentiometer 1 pin to the right, now it works!
- 39
4
votes
How to make an arduino button to forget his past purpose?
What you likely need is a state machine. The behavior of the actions depends on the state the program is currently in.
In your case, the state machine might look like this:
What does it mean?
black ...
- 1,058
4
votes
How to convert my Arduino setup to a PIC setup?
The PIC32 has full (or nearly full) support for the Arduino API through the chipKIT project. If you want to use one of the smaller PIC chips (PIC16 / PIC18 etc) then you're out of luck. There just ...
- 106k
4
votes
Accepted
Multiple Push buttons to one input
Michel Keijzers pointed out the issues you have in your code. But then
there is also an issue with your circuit: if you press any of the push
buttons, the analog input pin gets connected to one of the ...
- 45.1k
4
votes
Accepted
Why is my liquid crystal display not showing any output?
Your breadboard is one of those which have the power/GND lines interrupted between columns 31 and 33. I also once fell into this trap. If you look closely, you see that the blue and red lines are ...
- 1,306
4
votes
Request for help condensing code and saving memory
As a minor addendum to Edgar Bonet's excellent answer, you could simplify your code further and save even more memory by renaming your files.
In particular, instead of storing a list of character ...
- 141
4
votes
LCD displays more digits than serial monitor
The additional "6" seems to come from one of the first values. Maybe the first value printed is just a rogue value and all the following values are correct.
The point is that this rogue ...
- 16.6k
4
votes
Accepted
LCD I2C connection problems
Some common problems with LCD displays which incorporate an I2C backpack include:
Not using the correct I2C address for the I2C backpack. Use an I2C scanner to discover the correct address.
Mixing ...
- 1,192
3
votes
Can I control a cellphone's lcd (+touch screen)?
No. For two reasons:
You will struggle to find the pinout of the TFT (or even identify the model). It will have most likely been custom made for the phone.
The Arduino doesn't have a GPU to drive it. ...
- 106k
3
votes
Accepted
How to use a coma as the decimal separator?
Print the integer part, print a comma, then print the value minus the integer part.
float value = 123.45;
int ival = (int)value;
int frac = (value - ival) * 100;
Serial.print(ival);
Serial.print(",")...
- 106k
3
votes
Moving a character around an LCD screen - is there a better way?
You could encapsulate the logic of detecting a button release into its
own function:
// Return the button that was just released, or btnNONE.
int releasedButton()
{
static int last_button = ...
- 45.1k
3
votes
I2C LCD Serial Interface Board not displaying text
This can be due a lot of reasons, among:
Most common:
Backlight is set too low (there should be a small dial)
Circuit problem (recheck), and post it.
The I2C address is wrong, there are sketches to ...
- 13k
3
votes
Accepted
When the TX and RX pins for Bluetooth are connected the LCD screen will not update. Why is that?
You connected the LCD module to serial hardware pins 0 (RX) and 1 (TX).
When you receive the data from the Bluetooth module, through the software serial, you send it to the hardware serial.
if(...
- 1,682
Only top scored, non community-wiki answers of a minimum length are eligible