If you have about 10 hours to kill, you can use [Edje Electronics’s] instructions to install TensorFlow on a Raspberry Pi 3. In all fairness, the amount of time you’ll have to babysit is about an hour. The rest of the time is spent building things and you don’t need to watch it going. You can see a video on the steps required below.
You need the Pi with at least a 16 GB SD card and a USB drive with at least 1 GB of free space. This not only holds the software, but allows you to create a swap file so the Pi will have enough virtual memory to build everything required.
The build step not only has to create TensorFlow but also Bazel, which is Google’s Java-based build system. There are dependencies between the version of TensorFlow and the version of Bazel so you have to make sure the versions match as explained in the video.
The video is based on some older instructions on GitHub, but those instructions are not up to date and the changes required are covered in the video.