Informal caregivers take care of someone (usually a close family member) who suffers from a chronic illness. In this stressful situation, caregivers have a high risk of depression or loneliness, because their social network is weakened. Most existing proposals focus on helping caregivers fulfill caregiving tasks, instead of providing support for their mental wellbeing (e.g. identifying early stages of social isolation). We present a prototype ambient interface, called EmoTree, that makes communication frequency tangible by using a metaphor of a tree, and investigate user perception and motivation of use. People found Emotree to be interesting and enjoyable (78%), and useful (54%) unless the user does not suffer some type of problem (69%). Our preliminary results show the interface is easy to use and has an adequate representation of communication frequency. Our next step will make a second assessment with informal caregivers in their real context.