Before you can connect your ANT+ Garmin Device to your tablet / phone, you need to install some additional piece of software and set up a few things in your watch. Here is a detailed explanation of each step. 
A couple of notes first:


- Please read this tutorial to the end, including the "tweaking" section. 99% of people having transfer problems simply didn't follow the advice in that chapter. Please do.

- If you have an HTC or LG phone running Lollipop (android 5) make sure that you get version 4.14 of the ANT+ radio service from google play, because earlier versions don't work on your device. 

Some android devices have an internal ANT+ chip. A list is being maintained by dynastream here. Note that minor model differences matter: the S4 has a working internal ant+ receiver, the S4 mini and active don't. 

If your device is in that list, you can skip Step 1, as you won't need the ANT+ USB dongle. In Step 2, you need only the Radio Service (don't install other stuff). In most cases, it will come preinstalled. However, you have to set the "force ant+ scan" option in my app.

If your device is not in that list, chances are it does not come with a big, size A usb port, so you might wonder how to plug in your ant+ dongle. The answer is quite simple: you need an OTG cable like this:

in some [rare] cases, the android device is not bringing power to the usb, so the ant+ dongle won't be powered, and unsurprisingly it won't work. Please read Step 2 on this other tutorial to learn how to supply power. In this case, a y-cable is normally safe as well as the hub.

A small number of Android devices (mostly the Sony Xperia family) come with an internal ANT+ chip. In this case, you don't need the Garmin USB key. In every other case, you need the ANT+ USB key that you're already using with your computer. Before you go further, check the key version on the bottom: it should read USB2. USB1 keys are not supported at this time.
The app is also known to work with the Suunto Movestick and with the newest "mini" ANT+ garmin dongles.

In the end, I decided to base Sportablet on the ANT+ services from Dynastream. Unlike the Garmin ANT+ Agent you install on your PC, those ANT+ services don't know about your Garmin device, but know about the ANT+ hardware (the USB key, the internal chip on Xperia, etc). This should make my app a bit more future-proof (read: I shouldn't have to implement low-level drivers for new keys). We'll see :-). Meanwhile, that means you have to install two free apps (Android services actually) from Google Play:
- The ANT Radio Service (which deals with ANT+ channels)
- The ANT USB Service (which deals with the USB key). If you have an internal ANT+ chip (like the Xperia) you don't need this. See here for details on using an Xperia.

   Go ahead and do it! 

Note that those apps require your Android device to be properly classified by Google Play as one with USB Host capabilities. Some devices, which are host-capable, are not properly classified in Google Play. In that case, unfortunately, the ANT+ services will result "incompatible" with your device and you won't be able to download them. As they're provided by Dynastream, there is little I can do about it - you'll have to find an alternative way to obtain and install the APK (or convince Dynastream to drop the USB HOST requirement from their manifest, as I did for Sportablet). 

Insert your USB key. If you have a micro-usb connector, remember that you need to use a USB OTG adapter. This dialog should pop up from the ANT+ Service:

of course, you have to accept.
If the dialog does not pop up, your USB key is not being recognized by the ANT+ Service. That's not part of Sportablet, so I can't really help you much on this side. Please check the Google Play page for the two ANT+ Service apps, as there are quite a few hints from users in the comments section.

Now, if you want to double-check that it works, and you have a chest strap that you use with your Garmin, you can also download the free ANT+ Demo from Dynastream. It's a simple app that can connect with a chest strap or a scale and show you some values (it won't connect with your Garmin, just with the HR belt). If the ANT+ Demo works, everything has been set up properly. If you don't have a chest strap, just skip this step.

It's time to fiddle with the bezel a little and make sure ANT+ is properly set up. Although you've probably done this before to pair your Garmin with your PC, you have to do this again to enable pairing with your Android device, and to make sure that all the activities in your watch will be sent. The following pics are based on a Forerunner 405.

Choose Settings > ANT+ > Computer

Make sure that:

Run Sportablet. Don't click on Get new yet. First, make sure that your watch is not in stand-by, by clicking the top button. I've found that the watch transmits more reliably while in Time mode:

note: this part is no longer necessary with the latest version, I'll remove it as people upgrade:
UPDATE (July 2014). Due to a new version of the Dynastream Service, before you click get new please get into the options, scroll down to the ANT+ section, scroll down to the last entry (it should read "Force Claim Interface") and turn that ON. This is usually needed only if you use the ANT+ USB dongle, and not necessary if you have a built-in ANT+ chip in your phone.

Now click the Get new button. You may see that the app is trying to connect on different frequencies: that's ok as it's part of the ANT+ protocol. After a while, the app will ask you to accept pairing on your device:

do so by clicking the top button on your watch. After that, it should proceed as usual: Runs are downloaded, then Laps, then Tracks. At the end, the dialog will report how many new activities you got. Click Done to get back to your main screen. 

NOTE: if you're using an Xperia or another device with internal ANT+ chip, remember to click options, and set "Force ANT+ scan" on. This will force the app to try using the internal chip.


NOTE: it is often necessary to set up a few options in the app, as well as to set up your tablet / phone properly. So, if the process fails or times out, please read the following section. It is *very* important that you turn off wifi / data / 3g / etc on your android device.

ANT+ has very delicate timings, which can be easily disturbed by background processes, especially in a smartphone. So if you experience problems, the first thing you should do is turn off the GPS, Bluetooth, WiFi, data connection on your phone. This is known to help a lot, and honestly, is basically mandatory.

ANT+ is not particularly good at transferring long sequences of data, and the protocol Garmin adopted on top of it for the 405/410 family does not allow to retry on failures, so the combination is a little flaky on some devices. If you have any problem downloading long activities, Sportablet and the Uploader provides a few settings that you can try (under "options")

- First, make sure that diagnostics is turned off. ANT+ is very time sensitive, and on some devices even the time spent on logging seems to cause problems.
- Next, just enable "Delay Ack". Leave all the other ANT+ options off. This should give the watch a little more time to synch with the tablet during long bursts.
- If that still fails, turn "Boost TX power" on.
- If you still have problems, get in touch. The other settings are not effective for a 405/410.

It took me quite a while, but we're finally here. The first batch of ANT+ Garmin devices to be supported in Sportablet is the 405 / 405CX / 410 family. Version 2.9 includes beta-level support for this family. The Uploader for Garmin, version 2.1, is also bringing ANT+ support to small tablets and smartphones.

To use ANT+, you have to install a couple of services on your tablet. My previous post explains the entire procedure in full details. Please take the time to go through it.

Support is still in beta, which means:
- There is no graceful error handling if you do not install the required ANT+ services (again, see my previous post).
- There seems to be timeout issues inside the Dynastream service. There are a few knobs you can turn inside "options". Again see my previous post for full details. 

The beta is fully functional and safe to use. No data is ever written to the forerunner, so it's always risk-free. If the app ever hangs for any reason, the watch may stay in the "upload" mode for a dozen seconds or so, but will revert to standby or time mode in a short while.

Please send me a log if you try out the beta. I really need to check what is going on with different Garmin models and tablets / phones. The ANT+ log is very detailed and can get a little too long for some email apps, so:

- try the app with device diagnostics off, just to check that it works.

- if the app works, enable device diagnostics (under "my options"), turn on the watch again, and enable everything on your watch as you did before. The app will see that there are no new activities and will stop earlier. Send me that log with the red button, thanks :-).

- if the app does not work for your device / tablet, enable device diagnostics, set up your watch as described in my previous post, try to upload. The app will retry for a long while, so at some point you may want to stop it and send me the log.