Making a littleBits DIY Doorbell | attempts at using tech effectively in education
SURNICE Self-Powered Wireless Doorbell, No Battery Required Push Button, Waterproof Door Bell Chime Kit, up to 300m/1000ft Range with 38 Chimes, 4 Volume Levels & LED Flash, DIY Name Plate - Amazon.com
Wireless Doorbell using 433 MHz Reciever and Transmitter module
Making a Wireless Doorbell Circuit | Homemade Circuit Projects
Build a Wireless Doorbell Pager for the Deaf | Nuts & Volts Magazine
Wireless Doorbell Chime,Waterproof Plug in Door Bell Chime Kit Operating at 1300 feet,36 Chimes,DIY Name Plate Suitable for Home Office Classroom,White - Amazon.com