Here’s what I posted back in July, in another thread, regarding implementing cellular.
… don’t wait to proceed until you can get h/w enhancements from Rachio (LCD screen face, other things mentioned above, etc.) There’s no reason to not proceed now.
I work in energy monitoring and reduction areas. For our real time energy monitoring, we use a ‘black box’ approach exactly as Rachio does. The ‘black box’ has connected wires, it does processing, and it needs an Internet connection to function properly.
For the internet connection most of the time we connect our ‘black box’ to the customer’s Internet. But sometimes, the customer won’t allow for this, or there isn’t an Internet connection available. In this case we use a Wi-Fi to/from cellular communications ‘box.’ Work fabulously well.
We use CradlePoint’s COR IBR600 Series units - https://cradlepoint.com/products/cor-ibr600-series3 . We don’t bother with external antennas - performance in metropolitan cities where you have Verizon, AT&T, Sprint, T-Mobile, etc. is excellent.
We buy our units through distribution so I don’t know cost on retail market. I looked on Amazon - https://www.amazon.com/CradlePoint-COR-IBR600LE-VZ-Router-Verizon/dp/B00BCLCSJW1 - $645. A bargain for HOAs and commercial properties and areas where there’s acres and acres to be watered.
Slip in a SIM card, spend 5 minutes configuring the WiFi to ‘talk’ to the Rachio Iro, and you too are now in the business of running a sprinkler controller network without any wires. And it’s doable this moment - …
Put the Rachio in ‘automatic’ mode (flex daily), configure the Rachio, and 'let ‘er rip.’