My Home Control Project

  • I'm already well into a project, detailed here and updated here

    As you'll see I work with Intra red output, using the DHT and Dallas sensors, controlling outputs, running timers, Android interfacing and more. A problem I have had from day one has been reliance on the NRF24L01 radios which have incredibly poor range in stone buildings or when surrounded by access points and cordless phones etc. A bigger problem for me is reliance on the RF24NETWORK - which has not moved on for some time. Because of the way it is designed and uses fixed units as relays - this means that if a unit goes down there is the possibility of most of the network going down. It is important for my purposes to control everything from the master unit - as simultaneous communications can result in data loss.I found this out the hard way. I also need to poll stations rapidly to update the status of a given input for the mobile phone to maintain status.

    I have hopes that the network layer presented here is better. I have now a light board, relay board and gateway talking to a simple serial terminal and the only thing I've not figured out is how to rapidly poll a particular unit for status. I can see a deep understanding of the mysensors code is going to be needed soon.

    Of interest, I long since gave up on the 328 chips except for the simplest boards. I spent more time struggling to keep within the available RAM etc. The Atmega1284 chip is relatively cheap, compatible with these projects, is DIP so easy to use and has a ton of memory. Most of my new boards use this chip. As an example, take a simple board, put Ethernet onto it, add SD and already you're approaching the limits... use a 1284 and you've used less than 25% of available space at that point. For more info on that, look up "Manicbug 1284" on Google. All very exciting stuff. Something you'll not see here is use of the watchdog. This can be set for up to 8 seconds before it resets the chip. Handy for making boards that much more reliable.