Technology Tips from Thomas Eng: Direct Wi-Fi Pairing

Our new FIRST Tech Challenge control system requires that your Driver Station (DS) device be �paired� with your Robot Controller (RC) device.  The FTC apps use Wi-Fi Direct technology to establish this connection between the two devices.

If you are having problems pairing your devices, here are some tips:

1.  Make sure you pair the devices using the FTC Driver Station app.  

Users should not try to pair the devices from the Android Wi-Fi Direct screen.  Instead they should use the Settings->Pair with Robot Controller screen on the FTC Driver Station App.

     2. Make sure your devices are not connected to any other wireless networks.  

     If you are having difficulty pairing your devices, make sure your devices are not connected to any other Wi-Fi or Wi-Fi Direct networks.  You can use the Android Wi-Fi and Wi-Fi Direct screens to forget any �remembered� groups, then restart the devices and reattempt the pairing process. 

      3. Make sure your WiFi Direct names do not have a newline character in them.  

     There is a bug in Android Kit Kat which can cause problems during 

     a Wi-Fi Direct scan if it encounters a device name that has a newline 

     (i.e., a RETURN) character in it.  If a user inadvertently puts a newline character in the device�s name (for example, because their finger accidentally hit the RETURN key on touchscreen keyboard), this can cause problems during the pairing process.When you type in your Wi-Fi Direct name, make sure you do not have any newline characters included:

Figure 1 � For this device the Wi-Fi Direct name has a newline character before the �018�.  This can cause pairing problems. 

4. Are there a large (20 or more) number of pairs of devices trying to connect? 

If you are in a venue where there are a large number of devices trying to pair simultaneously, it could affect your Driver Station�s ability to find and connect to its matching Robot Controller. If there are a high number of devices attempting to pair at the same time, it might be helpful to remove your pair of devices from the immediate area and pair the devices in isolation. Once your devices have been paired, they should stay connected, even if your wireless environment has a fair amount of wireless interference in the background.

For detailed information about troubleshooting the Wi-Fi Direct pairing process, please visit the following thread in the FTC Technology forum:

http://ftcforum.usfirst.org/showthread.php?4690-Technology-Tip-WiFi-Direct-Pairing-(LONG)