WMBE Raspberry Pi mobile router

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Wikimedia Belgium owns a WMBE Raspberry Pi mobile router since August 2017.

This SoC appliance (a black box–literally) can be used as a mobile Wi-Fi accesss point to e.g. give Wikipedia training on remote locations that do not have a fixed internet connection, or when the local Wi-Fi is not available/reachable. It can be used for other occasions as well: conferences, board meetings, hackathons, edit-a-thons and other activities.

Because mobile roaming (billing) in Europe has been revoked in the summer of 2017 (thank you, EU) we can use the device in any European country. We can use up to 5 GB data per calendar month. This allows for up to 4 edit-a-thons with 5 participants during 2 hours (± 40-50 person-hours in total at 100 MB per hour).

The only requirement is a decent 4G connection.

Contacts[edit]

Functionality[edit]

The device delivers the following functions:

  • Mobile router (meaning you really can use it anywhere; even in places where there is no fixed internet)
  • (built-in) Wi-Fi access point with private DHCP
  • NAT router, and firewall (private WLAN security - the device can be connected to a local LAN uplink)
  • Could be used as a Wi-Fi relay (in case the local Wi-Fi access point is too far away)
  • Minimum hardware: Raspberry Pi, a mobile 4G USB stick, power supply (possibly from USB)
  • Operating system: Linux (Raspbian)
  • Can be powered from mains via adapter, or from USB battery (possibly UPS)
  • Mobile stick: send and receive SMS (no voice)
  • Internet backhaul connection (plug-and-play) – very flexible – you can transparently choose between:
    • Mobile 4G/3G data connection (using the USB data stick)
    • Ethernet LAN connection (using a LAN cable in an office)
    • WLAN uplink (requires an extra USB Wi-Fi dongle)
    • USB thetering (e.g. using a micro-USB cable from a smartphone)
Optional hardware
  • USB micro-Keyboard with built-in mouse
  • Normal USB keybourd and mouse
  • External USB disk
  • HDMI cable to connect to a flatscreen
Optional software

Components[edit]

Mobile router and Wi-Fi access point components
Subsystem Component Description
Main system Raspberry Pi 3, or higher Built-in Wi-Fi access point1,2
Micro-USB power supply3 Main(s) power, USB battery
USB 4G-stick4 Mobile internet, with data subscription
Alternative power supply5 Micro-USB cable Power from laptop
USB console cable (serial) System console via PuTTY or screen for system maintenance/troubleshooting
Optional GUI Mini keyboard and mouse pad6 Console or X Windows
Mini-USB cable To charge the keyboard battery
HDMI cable 5 m to connect a flat screen or an external projector
Optional fixed network Ethernet cable7 5 m to connect a laptop, or switch
Network switch Network ethernet hub
Ethernet cable(s) One for each client
Optional mobile network Smartphone, micro-USB cable Mobile USB tethering8
Optional video HDMI Can be used to connect a flatscreen to allow for demos
Notes
  1. The Raspberry Pi 3 has a 2,4 GHz Wi-Fi network with a limited speed of 15-20-30-40 Mbits/s depending on the local interference, and the client system
  2. The Raspberry Pi 4 supports highspeed 5 GHz Wi-Fi (up to 150 Mbit/s)
  3. It can use channel 1 or 11 (channel 6 is not advised due to HT40 conflict) with a bandwidth of 1×20 MHz HT20 (typically 30 Mbit/s)
  4. Normally a standard micro-USB AC power adapter can be used (Raspberry Pi 4 requires a high powered USB-C)
  5. The mobile 4G data stick has normally a speed of 15 Mbit/s (under good network conditions) to be shared amongst all connected devices
  6. The AC adapter could be replaced by 2 USB power cables connected to a laptop with AC power (alternative power supply)
    • One laptop USB port can only sustain 100 mA. Therefore you need 2 ports to power the Raspberry Pi
  7. You could connect a normal USB keyboard and mouse as well
  8. The fixed ethernet speed is limited to 100 Mbit/s (internal USB 2 interface). Gigabit ethernet for Raspberry Pi 4.
  9. Speed can be much higher (above 60 Mbit/s), when the hosting device supports mobile channel bonding

How to use[edit]

  1. Plug in the mobile USB stick in the Raspberry Pi
  2. Connect the Raspberry Pi to the power supply:
    • Option 1: connect an external power supply, or
    • Option 2: connect two USB cables from laptop (connect black first, blue as second)
  3. Connect the client laptop(s) to the Wi-Fi network WMBEGVP

The system should be ready within 1 minute. The red-LED (power indicator) inside the Raspberry should be steady-on, and not flashing. When the mobile network is ready the cyan-LED on the mobile stick should be ON (and no longer flashing).

Shutdown[edit]

  1. (preferably) Shutdown the operating system (wait for the internal green CPU LED to flash 10 times)
  2. Remove the mobile USB stick
  3. Remove the power cable(s) (when using USB from laptop: first the blue console cable, then the black power cable)

Technical details[edit]

Mobile network status LEDS[edit]

Data stick status
LED Status
Off (power) Off
Flashing Connecting or error
On Connected
Network status and speed
LED color Status Speed
Green 2G 100 kbit/s
Blue 3G 1 Mbit/s
Cyan 4G 10-15 Mbit/s

The network that is used depends on the local coverage. 4G internal coverage might be limited. Place the device near a window when you do not get a proper signal.

Power supplies[edit]

  • Connect the external USB power supply adapter to mains (simplest solution)
  • Or connect the black USB power cable and the blue USB console cable to a laptop (can run on battery) ⇒ you are completely mobile!
  • In that case you should power your laptop from mains, if possible, to have a longer autonomy

Wi-Fi access point[edit]

  • SSID: WMBEGVP

When to use[edit]

You are on a location where there is no internet. You want to provide internet to multiple devices via Wi-Fi. Possibly at sites where there is no electricity. You might need additional batteries and/or an UPS system.

Examples:

  • Meeting
  • Wikipedia training
  • Wikidata conference (limited number of transactions per IP address)
  • Training OpenStreetMap
  • Demo MediaWiki
  • When you are travelling and you do not have a smartphone
  • Can be used in Switzerland (no roaming cost with Scarlet)
  • Use a local data card, when you are in a non-European country

Caveat[edit]

  • Do not use it in non-EU countries[1] (prohibitively huge roaming cost; depending on your mobile operator)
  • The appliance contains a built-in DHCP server for the Wi-Fi hotspot WLAN only; you can use an ethernet LAN switch, or a second Wifi USB dongle, to connect to an uplink internet connection (no LAN IP conflicts)
  • You must have a decent power supply (internal red LED should be always on)
  • The cyan LED light on the data stick should stay ON; if not there is either a mobile network problem, a power supply, a SIM card, a mobile subscription problem, or coverage problem

Troubleshooting[edit]

Sharing IP address[edit]

  • You can only create a limited number of new Wikimedia user accounts from the same IP address. Ask the participants to create a user account from home.
  • For Wikidata there is a maximum number of transactions per minute from the same IP address. You might ask other participants to use their own USB or Wi-Fi tethering.

Verify the 4G data stick on Windows[edit]

When you might have problems, use a Windows laptop to troubleshoot.

  1. Connect the data stick to a Windows laptop
  2. Goto Windows Explorer
  3. Click on setup.exe (run it)
  4. Configure the device
  5. Click on connect/disconnnect as you wish

Now you can remove the data stick and connect it again to the Raspberry Pi

System check and setup[edit]

The mobile gateway on the 4G data stick is 192.168.8.1/24.

The WLAN IP address of the router is 192.168.40.1/24.

Via PuTTY SSH connection when connected to Wi-Fi:[edit]

You can login to the mobile router:

ssh wmbe@192.168.40.1

If the Wi-Fi network would not work, you need to connect via the console.

Via Windows PuTTY to COM port[edit]

Connect the blue USB console cable.

  1. Lookup the COM port on Windows configuration -> computer -> devices
  2. Connect to the serial COM port; speed 115200

On Linux via USB console cable:[edit]

  • Connect the USB console cable
  • Verify the USB device
ls /dev/ttyUSB?

Output:

/dev/ttyUSB0

or

/dev/ttyUSB1
screen /dev/ttyUSB0 115200

or

screen /dev/ttyUSB1 38400

Now you can login and verify or configure the device.

To close the session: Ctrl-a k y

Start the access point manually[edit]

Normally the Wi-Fi access point should start automatically via /etc/rc.local. In case there is a technical problem, or a reconfiguration, you can verify any errors via:

hostapd /etc/hostapd/hostapd.conf &

Configure a Wi-Fi uplink[edit]

vi /etc/wpa_supplicant/wpa_supplicant.conf

Check Wi-Fi hardware configuration[edit]

iw list

If necessary, adapt the hostapd.conf file, e.g. to change the Wi-Fi channel to avoid radio interference.

Verify the access point[edit]

Use Wifi Analyzer to visualize if the access point is really available, and to avoid any interference from other access points.

If necessary choose another (non-conflicting) channel.

Invoicing[edit]

The hardware costs 227 euro (including 80 euro for the USB 4G data stick). The monthly mobile subscription is 15 euro for 5 GB. Out-of-bundle traffic costs 50 euro / GB! Roaming is 10000 euro / GB... Luckily EU-countries are no longer applying a roaming tariff.

  • You can verify the data usage online
  • When the bundle forfait is reached we get a warning e-mail and SMS

Data usage: approximately 100 MB/user/hour. A typical edit-a-thon can easily use 1 GB for 5 users during 2 hours... so we could organise 4 sessions per month. A monthly postpaid invoice has to be settled.

Software upgrade[edit]

  • To update the Linux operating system, connect to a local LAN, and perform apt update + upgrade.
  • To upgrade the 4G firmware on the stick: connect the USB data stick to a Windows laptop and follow the instructions.

Notes[edit]

  1. Noorwegen, IJsland, Liechtenstein en Zwitserland are part of EU roaming with Scarlet