A recent news story about the 50th anniversary of WWVB got me to thinking about building my own WWVB receiver. I Googled “wwvb kits” and came up with the following:
- WWVB NIST Radio Time Receiver Kit
- WWVB Chiming Clock Kit
- WWVB 60 kHz Time Receiver Module with Antenna
Unfortunately, all of these kits use a little PC board made by a company called C-MAX, and the company has either discontinued making the IC that powers this module or simply quit selling this module in the U.S. As recently as a couple of years ago, Digikey actually sold this module for about seven bucks.
There are several Web pages that show how to interface the CMMR-6 module to an Arduino or a PIC processor. Here are two:
A couple of companies in the UK seem to still have the modules in stock. The price from a company called Earthshine is only six pounds, but that doesn’t include shipping, of course.
There are some plans that don’t use the C-MAX chip, but, of course, they’re much more complex. One guy designed his own receiver, but it’s quite a bit more complex than simply using a single chip. There are also several commercial receivers available, but the cheapest one I found is $220.
There are several Web pages that describe how to use the WWVB receiver modules from “atomic clocks.” One of the projects scavenges the WWVB module from a Sony clock. The second uses the module from an Atomix 13131. The Atomix 13131 costs as little as $13.
So, I’m still unsure which way I’m going to go here, but it looks as though hacking an existing clock might be the way to go, especially if I can find one at a thrift shop or garage sale.