Older people with dementia often decline in short-term memory and forget what to do next to complete their activities of daily living (ADLs), such as tea-making and toothbrushing. Therefore, they need caregivers to remind they what to do to complete these activities. However, the steady growth of aging population makes the (relatively) shortage of traditional care resources more and more serious. In this paper, we propose a prototype called CoReDA (Context-aware Reminding system for Daily Activities) to help elderly with dementia complete different ADLs instead of caregivers. By using the wireless sensor node - PAVENET, CoReDA can obtain elderly people?s information of tool usage in different ADLs. Based on this information, CoReDA uses TD (\lambda) Q-Learning technique to provide elderly people their personalized guidance to complete ADLs.