XBee Time Broadcast Clock

XBee Broadcast Time as received by Luscious Electric Delight – click for movie
(L.E.D. created by Leif Krinkle with Rob Faludi and Benedetta Piantella)

The real-time clock which broadcasts time to the entire ITP floor via XBee ZigBee radio is now complete. Its time signal can be picked up by any project on the floor that incorporates standard 802.15.4 radios, and used for anything from time display to inter-project synchronization. The XBee Time Broadcast Clock code is written in PIC Basic Pro. It now incorporates regular updates from NIST servers. Time is stored and maintained locally on a DS1307 real-time clock chip, available on a convenient breakout board from Spark Fun.

Schematic of XBee Broadcast RTC Clock (essential components)

To pick up the signal at ITP, simply set the PAN address on your XBee to C or CC (the c is for clock). The signal is simultaneously broadcast to all 65,534 addresses within that network. PAN C is in a human-friendly format and PAN CC is formatted to be easily machine-readable. Here’s sample Arduino code for reading and parsing the real-time clock broadcasts.

This project is the first in a planned series of objects that will create an “information landscape” at ITP. Each object will provide information that other projects and objects can use, along with publishing actions which are publicly available so that the object can be externally controlled.