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LoRa parts with RPi

Tue Apr 19, 2016 2:32 am

I'm surveying LoRa devices and assessing their suitbility for use with RPi. Adafruit have recently released a series of devices that are a board with a RFM9x part attached, both 433MHz and 900MHz. Link:

There is also a dedicated RPi expansion board with the exact same RFM9x part attached from Uputronics. Link: ... duct_id=68

I have concrens that the Adafruit board lists the following in the details:

> ~100mA peak during +20dBm transmit, ~30mA during active radio listening

This far exceeds the RPi GPIO design limits of 16mA/pin (or 51mA total). Thus, would this make Adafruit's device unsuited to be powered by the RPi GPIO?

How is the FRM9x part in the Uputronics being powered without damaging the RPi since it's being directly connected to the GPIO header? Furthermore, the Uputronics product allows two (2) FRM9x parts to be attached on the same board. So isn't that double the current (I) requirements?

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Re: LoRa parts with RPi

Tue Apr 19, 2016 2:51 am

The board has two 'slots' for the RFM95... CE0 & CE1;

Apparently PI in the Sky Systems only work with the RPi with the module in the CE1 position. The RFM95_6_7_8 modules are used by the PI in CE1 slot on the expansion board. Contact the distributor, but I suspect that they have the interfacting correct.

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