If all you want is a bluetooth/wifi solution, then there's tons of "solutions" on the market for this. See our "comparison" table on CrowdSupply for some options:

* https://www.crowdsupply.com/alt-shift/buskill

When I designed BusKill, I intentionally avoided wireless solutions.

BusKill is designed for situations where the risk is extremely high, and you'll find that the radio-based solutions aren't very secure. They're faulty and have huge surface areas of attack.