Isn't pin0 used in
Serial.begin(2400); // RFID reader SOUT pin connected to Serial RX pin at 2400bps
Which you are using?
Yes, the RFID reader uses pin 0. So it can't really over lap wit itself, right?
My mistake looks like.
you are not sending to the pc computer, but to the RFID reader. Ok !
I will sleep on that, and maybe tomorrow we can find the bug.
Good night
Good Night, and thank you for your help.
Good morning, (for me anyway).
Looking at the latest sketch, I see:
void setup() {
lcd.begin(16, 2); // set up the LCD's number of rows and columns
lcd.print(" Please Swipe");
lcd.setCursor(0, 1);
lcd.print(" Your Card");
That is the only place you use lcd.print() ,
not in your loop.
So, with this code, what are you seeing on the lcd now ?
Can you tell if the program is still running, or not?
you may blink the onboard light to tell. at the bottom of the loop add:
digitalWrite(13,!digitalRead(13));
What I see on the LCD is the same dark gray text on a blue background, but only for "please swipe etc.". Pin 13 blinks when I add that so the loop is running.
At the right hand side of your display, you can see some white part sticking out.
That is where the backlight is.
Is that lit (enough)?
If not, recheck pin 15 (should be 5 volts) and 16 (GND) of the display.
If you have the means, measure voltage there anyways to be sure your 5 volts doesn't drop too much (maybe because of a too large load).
What if you disconnect the RFID stuff, is the display OK then ?
I unplugged all of the pins that go to the RFID reader and the LCD worked perfectly, then I put the pin in one at a time and found that when the RFID is plugged into pin 2, then the LCD does that, thing.
I tried moving the RFID pin which went to 2, to something else, but it still affects the LCD.
@cole, not to be picky, but, looking at your code, it says
lcd.print(" Please Swipe");
lcd.setCursor(0, 1);
lcd.print(" Your Card");
it does not say "please swipe etc..". If you expect help, please give us correct answers. Did you get both lines, just one line, just the first half of the line?
I'm sorry I didn't specify, the whole block of text, "please swipe your card", both lines, are messed up when the RFID is plugged into the Arduino.
Ok you say it is printing all the characters you send to it, but it is messed up when you attach the card reader.
I assume "messed up " means bad contrast, or no backlight. Which. When it is dark, does it provide a light?
Did you solder the pins to the LCD board?
Is the LCD board plugged into data pin 10 of the arduino board?
Thanks, Jack
That /ENABLE pin is active low.
Disconnect the other pin, connect the power pins of the reader.
Connect the /ENABLE pin to GND.
Do you now have the same effect ?
If so, your power supply is suspected to be the culprit.
Are you powering from USB ?
The RFID reader is specified to take a maximum of 200 mA, i don't know about the LCD background LED.
But USB is some 400 or 500 mA.
Maybe you should try an other power supply in this case.
By the way:
It's not a good idea to disconnect and certainly not to connect anything to your Arduino while it is powered.
Don't do that unless you're absolutely sure you know what you're doing.
I plugged the /ENABLE to ground and now all the LCD's text is a dark gray. I m using usb, should i use a 9v battery instead?
You haven't told us whether you can see the backlight being lit or not, neither have you told us if you're able to do some measurements.
If you are, it will be still interesting to know the voltage you see at pins 15 and 16 of the LCD.
A new 9 volt battery will probably not last very long (but long enough to test).
Best would be to use an external power supply of 9 volts, or one that does a good job at 5 volts.
If you do, you'll still be using the on board voltage regulator of the Arduino, which might act up if you are drawing too much current.
Measuring is the best way to go.
I'm not sure if it's a good idea, but maybe you could use a USB phone charger.
Lots of them offer 1 A.
But i can't tell you how stable those things are.
The back light looks to be running fine. I used my cheap multimeter on pins 15 and 16 of the LCD and I got around 8.5 volts, does that sound right?
No.
It is supposed to be 5 volts.
If for some reason 9 volts would be there, then you would have big trouble.
Apart from that if you are powering from 5 volts, you can't get higher than 5 volts.
You're not putting a separate power on any part of your setup, are you ?
Most likely your multimeter is defective or used wrong.
What Arduino board are you using ?
I rarely use my very cheap multimeter, so the reading was probably wrong. I can try using a 9v battery or I can go and get some aa batteries.