Fragmentation has sometimes been a challenge on Android, with hardware from different manufacturers.  There are two steps in the Bluetooth transmissions.  First, the Android device needs to detect your Wind Instrument.  This only needs to be done once, and after that the Wind Instrument remembers your Wind Instrument (usually takes around 30 seconds or less).  The second step is the Bluetooth connection (time varies by phone, but could take 1-2 minutes). It is often simplest to open the API and set down the phone while getting the boat ready.  When Version 2 of the SailTimer API went into the Play Store, the connections became much more consistent and fast across a range of Android devices.  If needed on certain devices, shutting the phone/tablet off and on again should (a) allow the API to connect faster, and/or (b) display values for the icons such as battery level and send data to the Wind Gauge app.

If you see dots where your userid should be entered, there is a simple solution. Delete the API, get it again from the Play Store (https://play.google.com/store/apps/details?id=com.windinstrument.api) and log back in.  Then do not log out.  There is no reason to log out;  the API is designed so that you log in once, and just stay logged in.  Then you don’t need to worry about having a password or an internet connection when you are out in the boat.

In Android 6 (Marshmallow), Location Services needs to be turned on in Settings -> Location in order to use Bluetooth 4/LE.   Then when you open the API and scan for the Wind Instrument, it should be detected.

“Battery optimization” in Settings may be disconnecting background apps to save battery power.  Try turning that off, by selecting “don’t optimize”.

No, the Wind Instrument does not need PIN codes, and they are not asked for on iOS or most Android phones/tablets.  But if yours does give a message not asking for a PIN code, that may be because it also has hardware to connect to older Bluetooth devices. Here are some suggestions for trying to bypass a request for a PIN code.  Some are simple and some are more detailed…
First, for the basics: does your Android phone/tablet support Bluetooth 4?  The version of Android needs to be greater than v. 4.4.

The PIN code is not something required by the Wind Instrument, and is being generated by something in your phone, not by the SailTimer API. If the message is not disconnecting the Bluetooth connection, are you able to ignore or cancel that message in the API and go to a different app for viewing the wind data? (Or is the message in all apps, showing that it is from the operating system itself?)

To use the Wind Instrument, you should not do anything with Bluetooth in Settings (other than have Bluetooth turned on).  Restart the phone by powering it off completely then on, and open the API.  That is the best way to try the connection, without any other apps or settings interfering.

Don’t try to do the Bluetooth connection through system settings rather than through the SailTimer API.  Here is an example from Sprint with the Samsung Tab E, using PIN codes (which does not work with Bluetooth 4). https://support.sprint.com/support/tutorial/Pair-with-Bluetooth-Samsung-Galaxy-Tab-E/WScenario_542_62138_771_en_17-dvc9750001prd  This is not the correct method with the SailTimer Wind Instrument, but as you can see, Sprint tries to do a Bluetooth connection without using the API, directly in settings with PIN codes. That does not work with Bluetooth 4, only older devices from around 2012 or earlier.

Here is another obsolete explanation about PIN codes from Samsung regarding the Galaxy Tab E:  http://www.samsung.com/us/support/answer/ANS00050839/ . They say that: “If you are connecting to an older Bluetooth device, you may be asked for a PIN. The default PIN for many devices is four zeros—0000. Some devices have PINs specific to the device. The PIN will be in the device’s documentation.”

PIN numbers are not used with Bluetooth 4, only with older devices from around 2012 or earlier.

This may be a useful work-around to try…  Turn off Bluetooth in Settings.  Then open the API.  That will probably trigger a notification panel, saying “An app wants to turn Bluetooth On for this device – Deny / Allow”.  That is a message about Bluetooth 4.  That may start everything correctly, without any PIN request.

You may want to un-pair the Wind Instrument in Settings to try to cancel any previous setup like that. Go to Settings > Bluetooth > Turn On and wait for your list of devices to populate. Select your Wind Instrument on the list and then select Un-pair. You’ll be free to attempt to pair it again from the API.

You could also try clearing your phone’s Bluetooth cache. Turn off Bluetooth, then Go to Settings > Apps > All and clear the cache for Bluetooth Share anything else that says Bluetooth.  Tap “Force Stop,” then “Clear Cache,” then “Clear Data”.  Then restart the phone and turn Bluetooth back on. This should give you a fresh chance at it.

Let us know what works for you, and we’ll continue to update other users.