MakerSpace Send Raspberry Pi and Arduino notification messages to your desktop You've Been Notified

If you use sensors with a Raspberry Pi or Arduino in your home network, you may want to get desktop notifications on your Linux PC whenever some interesting event is detected. You can send messages via SSH or through simple TCP connections and display them with notify-send.

- By Pete Metcalfe

There are some great libraries and techniques that let you pass sensor data from micro- controllers to centralized data servers and IoT dashboards. If you spend a lot of time on your laptop or behind a Linux desktop PCs, there are also some simple options that you can use to push notifications from Raspberry Pis or Ar- duino modules to the Linux desktop. Two techniques that I like to use are

• Running a remote command via an SSH login

• Sending a message to a small TCP socket server script on my laptop (Figure 1)

Both of these approaches have their pros and cons. For a Raspberry Pi or a similar machine running a full Linux system, it's a simple task to log in to your desktop via ssh and execute some notification com- mand. Unfortunately, however, most Ar- duino modules don't support SSH. Also, depending on what you're doing on your local machine, you may not want to let ex- ternal devices log in via SSH.

The TCP socket server method offers more security, but it requires a small, four-line Bash script that you will need to run on your desktop. TCP client librar- ies exist for both Python and C/C++, so all wireless Arduino modules and, of course, all Raspberry Pi models support this approach.

notify-send and Zenity

The first step in getting remote notifica- tions working is to install a notification application. Two commonly used com- mand-line notification programs are Notify-send (a tool in the Libnotify package) [1] and Zenity [2]. Zenity is a great general-purpose dialog creator, whereas notify-send just does desktop notification messages.