(DIFFICULTY LEVEL: ADVANCED) Page added 28 Feb 2014
Running the rPi in “headless” mode – no monitor, no mouse, no keyboard.
“Headless” operation is NOT a class project. Many of you may choose to go this way, to avoid bringing a HDMI screen to class, but setting this up is up to you. If it’s too difficult, then use a HDMI screen and keyboard & mouse “like you were supposed to”.
It can be possible to use a laptop as the screen for your rpi. It requires some advanced skill. And there will still be times when you will need a REAL screen and keyboard.
The “BS1″ version of OS for SCCC (and later versions) has remote access included, using vnc. (But not the regular Raspbian!)
The screen’s pixel size is whatever you are displaying on your real physical screen, even if your physical screen is missing. So you hdmi screen folk might have screen at perhaps 1920×1080 or similarly huge. If you use an old AV screen it might be more like 640×480, or lower. If you have no screen plugged in, it defaults to AV mode.
A “vnc server” is already active and waiting on your rPi. You can run programs on the rpi looking at “virtual” version of the screen on your laptop. The laptop software is a “vnc viewer” or “vnc client”, and there are several flavours, but they all work.
The following is how to access the screen from your laptop.
- Both rpi and laptop need to be on your wired LAN. (Yes, it CAN run by wifi. That’s another level of complication.) Both machines will get assigned an IP number on network.
- You need the RPI’s identity (hostname or IP number).
- You run vnc viewer software on the PC, nominating:
- the IP or hostname of your rpi
- the password that I assigned for remote access (On BS1, I have set 123123)
Possibly, your vnc viewer may find your rpi directly by hostname (ie the rpi’s computer name as it appears on a network). Hostname is originally “raspberrypi”. But you should use utility raspi-config (root terminal, run “raspi-config”, select advanced, hostname – use keyboard, no mouse function) to set a unique hostname for your rpi, otherwise all the rpi’s in the class will have the same name!
If finding your rpi by hostname (on vnc) fails on your network (it varies by network, or by router), you must alternatively identify your rpi to vnc by its IP number.
Alternative: Finding IP number:
What IP number did the rPi get on the network? If you initially set up the rPi with monitor & mouse & keyboard still connected, you can use the network icon to the right of the red memory-usage icon in the tray. (That applet has its days. Sometimes we can read IP address from it.)
Or open a terminal and type ifconfig. Look for eth0 inet addr: It might look like 192.168.1.6 or 10.0.0.6 or 172.something.
BUT … the intention was to dispense with the rPi physical monitor! We want the LAPTOP to interrogate the rpi.
Perhaps a “ping raspberrypi” or “ping rpi-bl1″ (or whatever you named as the hostname) from the PC at a command prompt may find the rPi for you. Try it. Otherwise we need a more formal way to “scan” your local network. Solution is an “IP SCANNER” utility on the laptop.
Two (free) options are:
http://angryip.org/w/Download (32 bit Windows executable) Slower, but I like this better. but it uses java that some folk don’t like. (Make sure your java is up to date – V7)
Hint: Configure your scanner to not show “dead” hosts.
We can see the IP for this RaspBerry Pi. It’s 192.168.1.10 for my network (today). Probably you will just have your router/modem, your home PC and the rPi.
A vnc viewer:
Download from www.realvnc.com/download/get/1293/
Get the windows 32 or 64 bit REALVNC VIEWER as your pc needs.
Probably 32 bit unless you know you use a new 64bit machine. Free.
(If your laptop is linux, Remmina is a better choice of vnc viewer. Even your BS1 rpi has Remmina: view one rpi from another!!)
Realvnc-Viewer program on Windows executes immediately you click it, it doesn’t install.
You name the “vnc server” like this:
192.168.1.10 (IP address)
or like this:
rpi-bl1 (hostname) or raspberrypi (not case sensitive) if you haven’t renamed it, as above
Password is 123123.
… and BINGO – you’re in.
(Hint: huge pixel screen works slower in vnc.)
Subject: Raspberry Pi on an Android Tablet
Date: 27/04/14 23:04
Regarding “headless” mode – using no monitor (& maybe no mouse, no keyboard) on rPi.
Setup of headless mode requires some computer skill. Headless operation has NOT been part of our class instruction. But you are welcome to try it if you are game. Consider it an “optional extra”. Some of you do already use headless mode – and I use it in the tutorial room. Instructions for Headless Mode are given on our class website.
Now, note that the rPi screen can be displayed on to a tablet in lieu of to your laptop. Here is my setup for that:
- Remember to use raspi-config on your rPi to set a unique “hostname” to your rPi.
- I use an android, not iPad, but similar apps ought be possible with iPad. My android is the Harvey Norman $78 generic 7 inch one – it’s fabulous!
- I installed 3 free apps to my tablet: Net Scan, Fing, and AndroidVNC. The first 2 do a similar job, and just one of those will do: they are network scanners. Fing is more likely to identify the rPi’s hostname fully on your network, but either will find IP addresses. SEE FOOTNOTE
- AndroidVNC is the VNC client to view the rPi on. SEE FOOTNOTE
- Make sure your rPi is on your home network (or the SCCC club network)
- Make sure your tablet is on your wifi on same network.
- From the tablet, use Fing (or the other) to find rPi IP address.
- Use androidVNC to contact your rPi. Try for full colour. Remember VNC password of our SD image is “123123”
- On a tablet there is no right-click, but double tap often does that job. So opening by “double-tap, open” can start most things like a program icon.
- “Menu/Send Text” on the vnc viewer on the tablet can (awkwardly) send text to the rPi.
Eg “cd Desktop <return> sudo python blink12.py <return>”
can be entered and submitted to start a python script. (Dont forget those carriage returns)
- Generally tablet finger works different from a real mouse, and secondly tablet text sending is clumsy.
- But using REAL mouse & keyboard on the rPi can be used quite successfully with a tablet VNC screen, though. “Semi-headless?”
FOOTNOTE ADDED APRIL 2015:
Windows: an alternative IP scanner is http://www.advanced-ip-scanner.com/ Otherwise the instructions above for Windows are still essentially intact.
On my debian linux I definitely prefer angry ipscan as net scanner. It wasn’t in my repository, so …
I fetched the “deb” package file from http://angryip.org/download/#linux and it installed with gdebi.
On Android tablet I now use Network Discovery as preferred net scanner and Real-VNC as preferred VNC client. It’s GREAT as a proxy display, and quite serviceable even for key & mouse entry.