So, we decided to try and make a reusable wireless module for all the DigiSpeaker products. The idea is to FCC certify this single module and then reuse that certification in all our products.

The module is based on the MC13224 from Freescale. There isn't much to it. I tried to bring out a wide selection of the pins so it would be useful in a number of places. The module is a little large (1" x 1.4") but it does fit into a Dimmer design. It has two antenna configurations. The first one is a standard Inv-F PCB antenna. The second is simply a hole where a wire-whip can be soldered. Notice that the whip can be soldered on the top or the bottom of the module. The idea was that we might solder a whip to the bottom of the module and run it up through the front board of the dimmer and have it bend into the plastic faceplate of the dimmer.

The board is castellated. It turns out, that any board shop can do 40mil holes on 100mil centers when castellating. However, this design calls for 20-35mmil holes on 60mil centers. This is just on the edge of what a normal board shop can do. If it turns out that the modules are significantly more expensive than regular boards, then it won't make sense to use a module. Instead we will just place the radios in each design and swallow the FCC costs. I am in the process of bidding this design now.

The schematic is here.
The BOM is here.

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