Setting up a headless Pi for a workshop.

For the Gnome Street Gnome event I wanted to be able to run the workshop without the need for lots of HDMI monitors and keyboards. I also wanted the simplest set-up possible as I knew I'd likely need to do it multiple times. The organiser provided me with a pile of Pi3, each with an SDcard containing noobs.

I used the latest full Raspian image and flashed it to the SDCards using my laptop and Win32DiskImager. The image contains all the software needed pre-installed so saved me downloading more.

The raspberry pi 3 will happily run without a keyboard and monitor but I needed to configure the WiFi adapter before we could connect to them. The easiest way to do this would be to use a keyboard and monitor to do the setup.

As I did not have this, I used the console which can be accessed via a serial connection attached to the TX and RX pins on the Pi's header. I used a USB to TTL module, checking that it was 3.3v compliant. Mine was a CH340 based module and seemed to work fine. I connected TX, RX and GND, and powered the board from a second USB port or supply. Some boards also provide 5v power so check your documentation. On the PC you run a serial terminal such as Putty and connect it to the serial port, you can then access it in the same way you'd do from a command prompt on screen or SSH remotely.

To configure the WiFi I edited the wpa-supplicant config file, I then used the raspi-config tool to change the host name.

Node-red was already installed so it was set to run on boot using:

sudo systemctl enable nodered.service

Finally the boards were rebooted and we ready for use.

To make accessing the node-red designer straightforward, I installed the Bonjour software on the Windows laptop. This allows connection via http://raspberrypi.local:1880 rather than needing to know the IPAddress, this should not be needed if you are accessing via a Mac, Linux PC or tablet. The service part of this capability is already installed in the image.

Whilst researching this, I realised that there's quite a few steps that have been improved over the years which made my job a lot simpler than first thought.

I also tried the Raspian Jessie Lite version, that also works but you will need to install Node-Red and it's dependencies.

It was a good thing that I did not have to install anything during the workshop as the art centre WiFi required you to accept terms and conditions. I only realised this when we tried to play a WAV file of a police siren and all we got was noise. We had downloaded the file directly onto the Pi using WGET. I opened the file to see if it was corrupt and realised it was HTML! We got around this by downloading the files on PC and coping them over using WinSCP.

Summary

• Install Raspian on SDcard
• Configure to connect to WiFi
• Set unique host name
• Configure Node-Red to auto start

Reference

Writing SDcard

Access via serial port

Configuring WiFi via Command Line

Change Host Name

Node-Red on Pi