Sigma Designs has opened up its Z-Wave protocol to developers, allowing them free access to the Z-Wave Interoperability Specification and the Z-Wave Security Specification, which were previously only available to Z-Wave Alliance members under non-disclosure agreement. It’s a big move that looks likely to gain Sigma and Z-Wave a lot of momentum in the smart home space, ahead of what looks to be a busy holiday season if the expected Apple and Google smart home announcements arrive this month. With the move, Sigma is significantly opening up its Z-Wave technology since both the hardware and protocol needed to create Z-Wave products have become far more accessible to developers looking to adopt a low power mesh protocol for smart homes and…