emojis as research

As part of my search for instant and ongoing research during a presentation, I realized emojis might be a solution.  But the host needs to be able to control the emojis.  For example, I just need 3 to 5.  The rest are just confusing.  And, I need a way to record the emojis over time and/or by participant.  Trying to understand how meeting participants are reacting to the content/slides.  Thank you.