On Windows, use Firefox, Opera, or Chrome
On Mac, use Firefox, Opera, or the lastest version of Chrome (64-bit Chrome 39)
When you navigate to the 'Track Smiles' page, check the accept box on this pop-up and choose 'Run'
This means it can't access your webcam. Make sure you have allowed it webcam access at the top of your browser, and that you are not using Safari
If you are using Chrome on Mac, you may need to update Chrome to the latest version, from here
Press allow/approve/accept on any pop-ups that appear asking you about the Java plugin
Make sure you are logged in when tracking smiles
If you added https://smiletracker.herokuapp.com to your security exceptions list, make sure you are on the https:// version of the site, and not http://smiletracker.herokuapp.com
SmileTracker captures a smile when your smile intensity passes a threshold. This threshold is set adaptively based on your observing your smile intensity over time. If the threshold gets too high, you can refresh the page to reset it.
SmileTracker works best in even lighting. If there are too many shadows on your face, it might get confused!
If you have multiple tabs open in the same window as SmileTracker, the performance may suffer and it could miss one of your smiles. Move it into a separate window to get the best performance.