Connecting RAK13010 & RAK5802 to RAK19007?

WisBlock
1

Hello everyone,

I would like to use the RAK19007 base board with the RAK4631 core module.

I plan to connect three sensors: some using RS485 (via the RAK5802) and others using SDI-12 (via the RAK13010).

Is it possible to connect one module to a sensor slot and the other to the IO slot on the RAK19007? Or do I need a board that has two IO slots?

Also, considering my sensors have a peak current consumption of 500–700 mA, do you think the internal power supply for SDI-12 will be sufficient, or should I use an external power supply (e.g., battery + boost converter + MOSFET)?

Many thanks in advance for your help with my project!

Best regards,
Julia

2

Welcome to the forum @Julia

RAK5802 and RAK13010 are both IO modules, so you need the RAK19001 Dual IO Base Board to use them together."

For the power, the 12V on the RAK13010 is capable of only 300mA, you need to use the external 12V supply option of the RAK13010 to supply your sensor.
For RS485 sensors, it is the same, there is no 12V output on the RAK5802, so you need an external 12V supply for them.

3

Hello beegee,

Thank you very much for your quick and helpful response!

I think I’ll stick with SDI-12 communication for now.

For the external power supply, is a boost converter (3.3V to 12V from a LiPo battery) enough? Or would you recommend using a MOSFET switch to optimize power consumption?

I’d like to add an RS232 sensor, but I can’t use the second IO slot since I need it for an SD card module for data storage.
Do you think it would be possible to connect the sensor via the board’s UART port (J10 connector) besides my two SDI-12 sensors on the IO slot ?

Best regards,

Julia

4

For the external power supply, it depends on your needs. For up to 700mA on 12V, you will need something powerful. I doubt that a battery will last long with that power consumption.

For the serial connection, the UART on J10 is 3.3V only. You can use it, but make sure the voltage levels match. The SDI module does not use a serial port, it is using two GPIO’s for the communication.

5

For the external power supply, the consumption peaks at up to 700 mA (for a few milliseconds) for each of the three sensors.

For the RS232 sensor, I’m planning to use a level converter (such as the MAX3232).

Thanks again for your quick reply!

6

I forgot to mention that I plan to use the RAK12002 RTC. Does it duplicate the function of a MOSFET switch for powering my sensors?

7

The RTC is nothing like a MOSFET. It is a battery backup-ed clock that gives your system a precise time and keeps the time updated even if you switch off the power.

8

OK ! Thank you for the clarifications, I’ll think it all over.