I'm doing a home automation system which uses a RF transceiver(nRF24L01+) paired with an arduino to control the relays. Since these require low power DC to run I was researching on ac to dc when I came across capacitative power supplies. This type of supply is needed as there isn't enough of space to throw in a transformer in a back box.
My only concern here is if such a power supply is safe, cause I don't want my house burning down.
This is the circuit I've found so far : http://www.circuitsgallery.com/2012/07/transformer-less-ac-to-dc-capacitor-power-supply-circuit2.html