Hi community
I have a spare Truebner SMT100 soil moisture sensor RS485 lying around. Recently I discovered the Dragino LoRa-sensor RS485 LB
After doing some research I stumbled across this cool blog-post SMT100 with LoRaWAN (TheThingsNetwork) and Dragino | The whole world of electronics and gardening.
I am bit confused about following sentence: Please make sure that the USB TTL cable has 3.3 V level …The switches on the LoRa module must be set to 5V and Flash.
I am not sure if she is talking about the SW2 switch which does the following as per the Dragino wiki: SW2 defines the voltage level of BOARD_RX and BOARD_TX pins. It should match the external sensor voltage level.
question: As a 3.3V USB-TTL cable is recommended, why should I change the SW2 to 5V? The soil-sensor only gets connected to A,B, +5V and GND on the screw-terminals.
I dont want to fry anything, hence any clarification is highly appreciated
Best,
Andrew