People living with dementia (PLWD) often have sleep disturbances, which can cause substantial care challenges and may be related to dementia progression. However, collecting ecologically valid data on sleep disturbance in naturalistic settings has been difficult. As a result, sleep assessments in PLWD are generally limited to short studies in sleep laboratories or data collection from wearables, where compliance is problematic. In this talk, we will demonstrate how we use passive internet of things (IoT) sensors to monitor the effects of dementia on nocturnal behaviour and physiology.