WiFi

I wrote about the reasons for using WiFi in my previous post. Let me cover it in more details.

The Pros

1. WiFi is already present in most homes, the only thing you need is a wireless router.

2. Security can be taken care on a network level, no need for additional security on the end devices.

3. Simple interface from the PC/mobile to the end device (no need for bridges or border routers)

4. It is quite easy to extend the range by adding more routers to the network level.

The Cons

1. No mesh network, the end devices are directly dependent on the router

2. Slightly higher power consumption than in 802.15.4 network

The Hardware

I have set the following goals for the electronics; the circuit should be easy to build, it should contain little or no SMD components (two layer PCB board is acceptable), the circuit size should fit inside some standard size wall boxes (the largest should go inside Gewiss GW 48 003 junction box)

The use of a WiFi module was a logical choise and I spent quite a lot of time searching for the right one, until I stumbled upon this one:

It is called openPicus and it is a spin-off project of Eikon company.  It features 22 I/O pins, which can also be remapped to different functions. The default config has 5 digital input, 5 digital output and 4 analog ports, but this can be changed. It is based on a PIC microcontroller and uses the Microchip TCP/IP stack.

The team has prepared a wizard based development environment, which "hides" the complexity from the developer. You can find more about it at: http://www.openpicus.com.

The first PCB board I will build will support 5 blinds with commands, so the board will feature 10 digital inputs (5xUP and 5xDOWN) and 10 digital outpus (via Solid State Relay).

The schematics and the PCB are already designed. When I get the boards, place the components and test them, I'll publish the designs for the hardware.