Here are the three options I mentioned in clearer form…
Using the one with the Linux server and the USB device.
Using the one with the NodeMCU and LUA (@heythisisnate solution)
Using the one with the NodeMCU and Arduino IDE/C++ (@ogiewon solution)
(this solution also supports various Arduino boards as well as the NodeMCU)
Your old keypads won’t work with options 2 and 3.
Your requirements will help you decide which path to choose. Please note that using SmartThings as a home security system (i.e. Smart Home Monitor app) has some limitations as compared to your old alarm panel.
- No entry and exit delays
- No keypad support
- Uses the cloud for all processing = less reliable than dedicated alarm panel hardware
- Uses “Presence Detection” to arm/disarm the alarm. Presence detection is not 100% reliable and can therefore lead to false alarms or failure to alarm scenarios.
Most people feel that if you really need a reliable home alarm system, use a dedicated home alarm system.
If you like to tinker and do not expect 100% uptime, SmartThings as an alarm system is better than nothing. I have friends who had no home alarm system at all before ST. They are happy because they now have a solution that provides +95% more coverage than what they had previously (i.e. 0%) with no monthly fee and no expensive hardware.
There are a lot of forum discussions regarding using ST as a home alarm system. I recommend you spend some time reading to come up with a game plan.