Sending serial data form Arduino to Arduino

Hey guys,

I know what you're all thinking. This guy did not read the forums, because there are enough posts about serial data transfer.

Well, I did and it did not make my project easier.

The thing is, I want to have an Arduino to send data to another arduino when I turn them on. I don't want to have my laptop connected to the Arduino's. Instead I'll have a 3.5" TFT LCD on one of them.

I have a protocol for sending and recieving data. And with my laptop connected they both work, but when I disconnect my laptop and connect the Tx from the sending Arduino to the Rx of the recieving one. As well as the Rx to Tx ofcourse. Nothing happens. Whilst my code is simply telling te arduino to send data at a frequency of 10 Hz or so.

I would like to know what I am doing wrong or forgetting. I've set-up the connection like I'm supposed to. Serial.begin(115200) and such things are all included.

When I connect the sending Arduino to my laptop, it does not send anything until I open the serial monitor! So I'm assuming it wants to see a reciever first. how do I do that on the Recieving Arduino?

...ZweedNaat

A diagram of your wiring and the code for the transmitter and receiver is, I think, necessary to help us help you. Please read the how to use the forum stickies to see how to format and post code. And this link will explain how to post images.

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data.

...R

ZweedNaat:
I have a protocol for sending and recieving data. And with my laptop connected they both work, but when I disconnect my laptop and connect the Tx from the sending Arduino to the Rx of the recieving one. As well as the Rx to Tx ofcourse. Nothing happens.

Just to be sure: serial needs three wires. Tx/Rx, Rx/Tx and Gnd/Gnd. Do you have a shared ground?

When I connect the sending Arduino to my laptop, it does not send anything until I open the serial monitor!

No that is wrong, it can send stuff if nothing is connected.

Do you know that when you open the serial monitor the Arduino will reset due to the Auto reset circuit.

Code and schematics posted and then we can tell you what you are not doing that you think you are doing.