The AffectButton is a thouroughly evaluated interface component for affective labeling and feedback on three dimensions Pleasure, Arousal, and Dominance. It is interactive, easy to use and embed in your code, and we have performed a series of evaluation studies showing that its measurements are valid and reliable. It has been used to gather affective feedback in for example the following settings: perceived mood in music, preferences, perception of virtual characters and robots, person's mood, situational descriptions and affective words. It is downloadable in Java, HTML5 (Jquery also for mobile devices), and Python.
AffectButton: Towards a Standard for Dynamic Affective User Feedback
Joost Broekens, Willem-Paul Brinkman (2009). Affective Computing and Intelligent Interaction (ACII) 2009.
AffectButton: a method for reliable and valid affective self-report
Broekens, J., & Brinkman, W.-P. (2013). International Journal of Human-Computer Studies, 71(6), 641-667.