urgent !! help me please

2 DAYS only left for my graduation project ! BUT I still have a problem with ARDUINO DUE !

the board is powered using 12Vdc through the power jack.. it control LCD 4*16 through 4 bit data pins .. and also control the speed of three pumps through chopper circuit ( two of them controlled by PWM and the other by digital pin)

her is the problem ! the LCD work perfect alone .. but when I connect any of the pump to the arduino the LCD become completely unstable :(

pleaaaaase heeeeeeeeelp me please

You got this assignment last Wednesday, right ?

Did you try fully isolation of the pump controller ?

If you are in a hurry, why don't you tell us all there is to be told ? Now you have to tell your story over and over again until all relevant information to be able to help, is known. That doesn't help if you don't have time, does it ?

all the story is when i connect the pumps to arduino LCD become unstable ?

Are the pumps working off the same 12V supply as the Arduino?

Could you problem be due to transient voltage spikes on the 12V supply generated by the pumps?

The electrical noise from the pumps is resetting the Arduino.

You need an external power supply for the pumps - connect only the grounds and control wires - and make sure there is a diode across the motor to clamp the back EMF (it should have the band towards the positive side, so it won't normally conduct).

You certainly cannot have pumps powered through the regulator on the board, if that's what you were trying to do.

Have you tried a bigger power supply or separate power supplies? When you connect the components together do you create a short?

I don't think this type of problem has ever come up before, except maybe yesterday, or the day before, or last week, or May 14, or last month, or all of the above. Have you looked through any of the previous posts?

Try a search (in the upper right corner of the page) for topics that include LCD along with garbled, weird, strange, unstable, etc.

Don

Note: This answer was in response to the particular cross-post that was in originally the 'Displays' section of the forum.

arduino and pumps supplyed by the same 12Vdc battary .. i will try to supply each of them with seperate battary

Hi, to help us help you quickly.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Can you please post a copy of your sketch, using code tags? Please use code tags.. See section 7 http://forum.arduino.cc/index.php/topic,148850.0.html

Tom.... :)

A circuit would be good.

If the problem only happens when you run the pumps, it is probably due to electrical interference.

Use 0.1uF capacitors across the pump connected to the digital output.

The PWM causes a lot of interference but I am not sure of the best capacitor to use.

Weedpharma

How are all of these other devices powered? Please draw a schematic.

The backlight on most LCDs is too much for the regulator on the Arduinos. The Due is better than the others but not by much. The backlight should be powered from a regulator which can deliver the current required.

Do the pumps actually work and it's just a display problem?

Can a Mod please merge the cross-post that ended up in the Due folder? (There may be more.)

arduino and pumps supplyed by the same 12Vdc battary .. i will try to supply each of them with seperate battary

This is really not a good idea at all. You would need a lot of add capacitance (at least 1000uF ) across the 12V and the 5V lines (especially the 5V lines) to prevent the issue you are having. As mentioned, you really need separate batteries.

Another cross-post. The version in "Project Guidance" seemed to be getting more answers than any other copy.

Do not cross-post. Do not cross-post. Do not cross-post.

Do not cross-post again!

Threads merged.

Hi. Please so we can help, Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

We need this to help us, help you.

Tom...... :)

MorganS: How are all of these other devices powered? Please draw a schematic.

The backlight on most LCDs is too much for the regulator on the Arduinos. The Due is better than the others but not by much. The backlight should be powered from a regulator which can deliver the current required.

Do the pumps actually work and it's just a display problem?

all devices is powered using 12Vdc battary and 5 volt regulator (7805)

...

yes, the pump work and it's just a display problem

No it is not.

Take the advice given and stop cross posting!.

I'm done here.

Just an aside here - apart from the foolishness of cross-posting - but ...

What on earth makes you think that titling an enquiry here "urgent !! help me please" will in any way whatsoever encourage people to assist you.

Especially when it demonstrates that you have totally ignored the instructions on how to use the forum (item 6).

He has obviously not read how to use the forum (item 13) so he probably doesn't even know (or care) about what cross-posting is.

Don