I have a second doorbell because the one in the living room is too far away to hear from the computer - especially with music playing - but it uses up AA batteries far too quickly and I don't easily notice that it's no longer ringing with the main one. So I connected it up to a USB port instead...
January 2008 Archives
I've finally finished putting together the parts to connect multiple NTP reference clocks to the same serial port...
It uses three reference clocks - one GPS receiver and two radio clocks (DCF77 and MSF).
![[USB powered doorbell]](http://simon.arlott.org/photos/thu/2008_01_27_19_24_45.jpg)
![[Inside of box]](http://simon.arlott.org/photos/thu/2008_01_19_22_45_57.jpg)
![[MSF receiver]](http://simon.arlott.org/photos/thu/2008_01_19_22_47_46.jpg)
![[DCF77 receiver]](http://simon.arlott.org/photos/thu/2008_01_19_22_56_17.jpg)
![[GPS receiver]](http://simon.arlott.org/photos/thu/2008_01_19_23_15_30.jpg)


