I have a Nokia 6610 LCD, which is connected to an Arduino Mega.
When the Arduino Mega is powered with USB from my laptop, the LCD connected to Mega plus everything else work well.
As soon as an external power supply is connected to the Mega, the LCD does not work at all!
When I say external power supply I mean a L7809CV voltage regulator.
Why is this that with USB everything is fine but not with the voltage regulator?
Any help is very much appreciated.
Regads,
M.
When I say external power supply I mean a L7809CV voltage regulator.
It takes more than a 7809 to make a power supply. What other components are you using and how are they connected?
Don
I am only using a L7809CV, nothing else.
I have done exactly the same setup by using the same LCD and an Arduino Mega + an L7809CV and everything worked fine! But not this time for some reason!
Hope you can help.
Regards,
M.
I am only using a L7809CV, nothing else.
Then you are missing two capacitors and some sort of source of electricity.
Don
Which caps do I need and where do I need to connect them?
My source of electricity is my car.
So you think if I add the caps the problem will be solved?
M.
Which caps do I need and where do I need to connect them?
You haven't provided a link to the 7809 datasheet that you are using so I can't refer you to the appropriate figure. Look for a section with typical designs and look for a 'fixed output regulator'. It's usually the first design since it is the simplest.
The electrical system in a car is just about as noisy as they come. The power supply capacitors may not be all you need to fix your problem but it is not likely you can get away without them.
Don
Here is the datasheet:
Thanks.
matinzk:
Here is the datasheet:http://www.farnell.com/datasheets/76220.pdf
Thanks.
Did you find what you needed?
Don
Figure 4 on page 4 might be the solution?
Just add 2 caps to the circuit?
M.
Just add 2 caps to the circuit?
That is where you start. As I said before the power supply capacitors may not be all you need to fix your problem but it is not likely you can get away without them.
Don
I have tested the Arduino Mega with an external 12 volts, 1 amp power supply. The LCD does not work at all!
As mentioned before, when connected to a USB cable to my laptop, everything works fine!
Any ideas?
A 7809 is a +9v regulator, are you sure you have this right?
Are you feeding the 9v to the Arduino regulator?
Yes, 7809 is a +9v regulator and I have this correctly, and also correctly connected to the voltage jack input of the Arduino.
Is that what you mean?
It's all sorted now.
The cables from LCD to Arduino were too long.
Thanks.