Fighting with computers

There are multiple ways of learning what is the IP address your Raspberry Pi is obtaining from a router. The most obvious one is to use the router's DHCP client list. Another one is to use a HDMI display as your RPi will report its IP address while booting. The former requires administrative access to the router, which may not be possible on certain networks and the latter is only possible if you can connect the display to the RPi and you have a display available. What I am going to propose requires no special rights over the network gear not any additional hardware. One of the things you can do over a network is to broadcast a message (in fact this is the foundation of the DHCP protocol for a computer to find a suitable DHCP sever over the network without previous knowledge of it). Sending a UDP broadcast message allows any other system on the network to hear it. And if that message is received each receiver knows immediately the sender's IP address. So here is what I

I am working on a project that required some computing power and commanding an Arduino UNO running GRBL. Things have changed quite a bit from original plan, so because radio reception was awful, the original plan of using dump1090 with a USB dongle had to be ditched. Of course I only learned that once I have it working nicely on the Raspberry Pi 3. Plan B would be to use the Ethernet network interface. Once that was working we realized it was not possible on our target installation. Plan C was to use wifi. And while it is really simple to get it working with stock Jesse, I found a way to waste my time when I added spaces in between variables and equal signs in /etc/wpa_supplicant/wpa_supplicant.conf . So now you have been warned. # Include files from /etc/network/interfaces.d: source-directory /etc/network/interfaces.d auto lo iface lo inet loopback iface eth0 inet manual auto wlan0 allow-hotplug wlan0 iface wlan0 inet dhcp wpa-conf /etc/wpa_supplicant/wpa_supplicant.