We present in this work a Lightweight Transaction Protocol (LTP) for enabling constrained embedded devices’ interaction with multiple types of blockchains via the LoRaWAN communication protocol. The proposed protocol provides the benefit of interacting with multiple blockchains with only 13.5% decrease in battery life. The protocol also includes a gateway module API that connects to blockchains and generic smart contracts to authenticate end devices and store their data. The study points out that, in the worst case, end-device data can be stored in blockchains with a latency of 20.3 seconds for Substrate and 6.8 seconds for the Hyperledger Fabric blockchain.