Receiving garbage data between 2 system with softSerial

Using Arduino Programming Questions
#1

Im receiving alot of garbage data between my 2 systems, which is connected via a wire, as you can see on the picture of my project. Im 90% sure that the problem why i receive all that garbage data is from the wire cause the problem disappears when i disconnect the wire from the LCD system (on the left). I know a wire can act like an antenna but it haven’t been this bad before that I cant send anything from my keypad system to my LCD system because of all the noise its receiving. So do anyone know how i can fix it? :wink:

This was made in a school project and I wanted to finish it after.

106896413_3005310966255547_4345566371461544037_n.jpg
106896413_3005310966255547_4345566371461544037_n.jpg1728×792 160 KB

#2

Please post a wiring diagram. It's impossible to see how things are connected. Also schematics, since you must have made them before making PCB's. :slight_smile:

#3

here you go its not 100% the same but there have been some fixes to the keypad from pin 0 and pin 1 to the communication cable. Its in danish

projekt.pdf (144 KB)

#4

GOT this too :smiley:

Schematic_Diagram_2020-07-11_21-43-47.pdf (98.8 KB)

Schematic_Diagram_2020-07-11_21-43-36.pdf (98.8 KB)

#5

You need to connect the grounds between the two boards. Also, please post your code in tags.

#6

Will it fix it if i just use the same power supply?

#7

matti1999:
Will it fix it if i just use the same power supply?

Yes, assuming the power supply ground is the same as the module ground. Usually it is.

#8

It seems to have worked. How can it be that not having the same ground can make so much noise?

#9

matti1999:
It seems to have worked. How can it be that not having the same ground can make so much noise?

Think "antenna".

Paul

#10

matti1999:
It seems to have worked. How can it be that not having the same ground can make so much noise?

A voltage signal without a reference (i.e. ground) is completely meaningless. There's absolutely no way to get valid data from a voltage signal without a common reference/ground.

#11