Infrastructure & Assembly

We used the following components to build up our client infrastructure. Note that links provided are just proposals for your convenience, other components will also work.

• a FLARM device
• a ​Raspberry PI
• Power supply:
  • As Flarm is running on 12V and to ease use of a mobile flarmradar gound station powered by a 12V battery, we recommend a 12V power supply for the flarmradar ground station (FGS)
    • Use a standard power converter (e.g. ​RS-Online) if an electical outlet is available to power the FGS
    • For battery powered FGS, use a 12V battery as used in most gliders
    • To connect the FGS to external power supply or battery, use a connector, which is protected against polarity reversal (e.g. ​RS-Online)
    • To protect your Flarm against over current, a 500mA fuse should be installed in the power supply route to the Flarm (e.g. ​RS-Online)
    • To connect your Flarm to the FGS, we recommend installing a RJ45 connector on the FGS front panel and to use a short network cable to connect the FGS to the Flarm
    • For pin assignment of the RJ45 please consult ​Flarm Installation Manual
    • Wiring instructions: 12V DC In --> Flarm fuse --> RJ45 connector --> network cable --> Flarm
    • Alternative way of Flarm power supply: ​update cable
  • Raspberry is running on a 5V power supply therefore the 12V power supply must be converted to 5V for the Pi.
    • Power conversion can be performed using DC/DC converter. Make sure the DC/DC converter can deliver at least 1A.
    • To protect your Pi against over current, a 500mA fuse should be installed in the power supply route to the Pi (e.g. ​RS-Online)
    • Use a Micro-USB connector to feed the power into your pi
    • Wiring instructions: 12V DC IN --> Pi Fuse --> DC/DC converter --> Micro-USB connector --> Pi
    • Alternative way of Pi power supply: A USB charger to power the Raspberry, just make sure it can deliver at least 1000mA
  • All in one power supply: The Mean Well power converter ​ADD-55A offers 12V and 5V power output which can be run on standard power supply (88-264VAC) when available. If no power line is availble the device features a battery connection, which serves as backup power source.
• Flarm <--> Pi Data connection
  • Flarm delivers RS232 signal on its data port. To feed this signal into the Pi, there are presently two alternative ways of doing:
  • RS232-USB-cable
    • Buy a RS232 to USB converter cable. Preferable one which uses the FTDI chipset (e.g TBD). If you use a different chipset, this may not be supported by default by the Pi operating system.
    • Attach the converter to your Flarm and to one of the USB connectors on the Pi
  • Serial-In of the Pi
    • The Pi features a serial interface (UART) on its GPIO pins.
    • Pi's serial interface works on 3.3V. Hower, Flarm supplies higher signal levels. DO NOT CONNECT THE FLARM DATA LINES DIRECTLY TO THE PI'S GPIO PINS!!!
    • Buy a RS232 to TTL level shifter (e.g. ​E-Bay - costs less than 2 EUR)
    • Solder Flarm's TX, RX and ground (coming from the RJ45 jack) onto the RS232 side of the level shifter. Most level shifters have well labeled soldering pads
    • Solder 4 wires to the TTL side of the level shifter. Ground, +3.3V, TX and RX need to be connected
    • Buy a 2x13 IDC connector which attaches to the Pi's GPIO pin headers (e.g. ​RS-Online)
    • Connect the four wires coming from the TTL side of the level shifter to the IDC connector. Pin layout depends on the version of your Pi. See ​GPIO Pins. If you have a revision 2 Pi, this is the pin connection: Pin1=+3.3V, Pin6=GND, Pin8=TX, Pin9=RX.
    • Disable console output and boot messages on the serial interface. See ​here

• optional, recommended for a stationary installation: we use currently an ​external antenna

Knowledge & Troubleshooting

• Raspberry PI specific issues are collected on a separate page