thanks a lot. I am looking for the longest time to get temperature sensors for the various radiators of our house's heating system (temperature of pipes entering/leaving each radiator plus room temperature, wall temperature). I found no suitable ready-made Zigbee sensors and developing my own seemed like a daunting task. Your setup looks like a very realistic option for my project.
That's a cool use case. You should be able to use several DHT22 sensors per unit without too much trouble. If I were you, I'd consider mounting the unit on the wall near your radiator, then running some flexible 3 wire cable to all your various sensors.
I'd say the strength of my project is that it's fully open source and designed for casual hackers. The code is only a few hundred lines, and the hardware is all cheap commodity stuff.
The downside is that you'll need to get your hands dirty to set it up. But, there's a big upside in that you'll never get locked in to a proprietary service.
