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README.rst

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RAK811 based open/close sensors LoRa node

LoRa node can be used as a 4 button remote control, or a mix of different kinds: float switches, reed switches, vibration, inclination, etc.

Features

  • up to 4 digital i/o
  • led indicator for Join Ok and Tx ok
  • periodic transmission time configurable via downlink
  • enable/disable sensors and led via downlink
  • sleep between transmissions

Hardware setup

  • Tie a 470k pull-up resistor for each of used RAK811 input pins: 3 (PB14), 4 (PB15), 14 (PA15), 16 (PB5)
  • Tie each of the used sensors between their respective input (3,4,14,16) and Gnd
  • Tie a led between pin 8 (PA12) and Gnd with a 470 Ohm resistor
  • Make a voltage divider ( 1.6 M | 1 M ) to monitor battery voltage to pin 20 (PA2)

Behavior

Every time a sensor changes its state open-to-close or close-to-open the module leaves sleep, transmit a packet, and goes to sleep again. The minimum transmission time between successive sensor status change is 5 seconds. The module also transmits sensor status in a periodic way

Data frames

Data frames were based on cayenne LPP V2.0

Uplink fport 1

1 byte 1 byte 1 byte 1 byte 1 byte 2 byte
0x01 0x00 Digital Input status 0x02 0x02 Battery voltage (0.01v) units

Digital Input status bits 0-3: pin logic level value

Digital Input status bits 7-4: wich of the input pins caused the interupt

Downlink fport 11

1 byte 4 byte
0x02 periodic transmission time (1 second) units

Downlink fport 14

1 byte  
I/O pins enable/disable mask  

I/O pins enable/disable mask bits 0-3: Digital input pins

I/O pins enable/disable mask bit 7: Led output

bit value 0 = input/output disabled bit value 1 = input/output enabled

Disable an input is only recommendable when a sensor has a mechanical failure, giving false readings, and isn't possible to physically unplug it.

After sending a downlink config frame, the next transmission of the node will be a config response frame.

Provisioning

As the code was derived from a RAK Wireless existing product, it uses de same AT commands for provisioning using UART. Here is the manual with the complete AT commands.

Power consumption

RAK811 module current in sleeping mode is around 10uA. Every closed sensor adds approx 5uA in sleep mode. So the worst case scenario with all 4 switches closed in sleep mode will be around 30uA.

Tested environment

  • RAK RUI version 1.0.0 beta
  • FIRMWARE V 3.0.0.14.H
  • Bootloader 3.0.4
  • RAK Device Firmware Upgrade Tool v1.4 for Ubuntu Linux

License

This is an Open Source project and is licensed under a MIT License