Sending UDP mesages- working on Photon but not Electron

I’m trying to send a UDP message to a nodejs server that I wrote. I am not expecting the server to send a reply back.

This is working on my Photon but not my Electron.

Top of my .ino:

UDP Udp;
IPAddress remoteIP(54, 149, 36, 255);
int port = 9000;

and inside my loop:

                String udpString = String::format("B%.1f", fuel.getSoC());
            	int str_len = udpString.length() + 1; 
                char buffer[str_len];
                udpString.toCharArray(buffer, str_len);
                if (Udp.sendPacket(buffer, sizeof(buffer), remoteIP, port) < 0) {

My electron is publishing “Error”.

Any ideas? The IP address / port is public & open to the world (go ahead and try it :)). My Photon can publish to it no problem.

Where are you calling Udp.begin()?


You need to call Udp.begin() after Cellular.ready() returns true. In the default automatic with system thread disabled, setup() is fine. However, if you are using SEMI_AUTOMATIC or MANUAL or are using threading, you’ll need to add additional checks.

Aah - I just realized that in my Electron code, I wasn’t calling Udp.begin() at all!

Will confirm tonight but I’m sure that will fix it. Thank you!