/Mini-LoRa

Arduino Mini Lora Battery/Sensors Board

Primary LanguageEagle

Mini Lora Node, Arduino Mini LoraWAN sensor

At the begining this PCB has been created to help wiring between Arduino Mini and RFM95 Lora module and to be able to put the whole thing powered by various Batteries type (AA, 18650, A, ...).

Then I decided to add some funky stuff like:

  • Easy to build and solder, 0805 or PTH components
  • I2C connector (or grove) to be able to add internal/external sensors such as BME280, SI7021 or HTU21D
  • Footprint for Lora RFM95
  • Footprint for a Microchip 24AA02E64T EUID
  • RBG Led
  • Optionnal Tactile Switch
  • Various Battery Connector and type AA/A/18650/CR123
  • Two A4/A5 pins position so you can use different Mini Clone (see BOM)

Detailed Description

No specific documentation for now, it's just a kind of wiring helper as follow

 Arduino Mini   RFM9x Module
 A0          <----> RST
 MISO  (D12) <----> MISO
 MOSI  (D11) <----> MOSI
 SCK   (D13) <----> CLK
 SS    (D10) <----> SEL (Chip Select)
 D2          <----> DIO0
 D7          <----> DIO1
 D8          <----> DIO2

 Arduino Mini    Shield PCB
 D3          <----> Push Button (Has Pull Down)
 D9          <----> Led Red
 D6          <----> Led Green
 D5          <----> Led Blue
 SDA (A4)    <----> I2C SCL Connector
 SCL (A5)    <----> I2C SDA Connector

Installation

If you're using Battery clip connector, please isolate the A4/A5 and FTDI (V1.0 only) pads from clip because it will do shorts and prevent I2C to work.

I'm Using the LMIC stack as his with custom sketch, this one is under NDA for Ultra Low Power, So I can't provide it but you can use the one in example of LMIC.

You may need to disable debug of LMIC stack if missing.

I'm also changing the Bootloader to use optiboot and win 1.5K of flash code and setup the Brown Out Detect to 1.8V to be able to works under 2.7V. Please see this Pro-Mini-ICSP-FTDI repo if you need to flash your Arduino Pro Mini with this bootloader. You'll see in bootloader folder, I've compiled some for various Speed and for 8MHz and 16MHz Crystal (I use the 250KBPS one, it's fast and reliable).

Schematic

Boards

Top & bottom side

Top & bottom side Grove

You can order PCBs of this board at PCBs.io

PCBs.io give me some reward when you order my designed boards from their site. This is pretty good, because I can use these rewards to create and design new boards and order boards for a discounted price, so if you don't care about PCB manufacturer please use PCBs.io.

Assembled boards with sensors

Fully assembled with sensors

Sensors values en Cayenne Monitoring with external sensors

Bill Of Material

Nothing fancy, all components are 0805 and/or PTH and can be ordered almost anywhere (digikey, mouser, radiospare, ...). use only what you need dependings on what you want to do.

  • Arduino Pro Mini (just take care your board has A4/A5 at the correct place, some clone are not)
  • RFM95 (check Frequency)
  • Microchip 24AA02E64T EUID
  • Common Anode RBG Led, search diffused 5MM RGB LED common anode on ebay
  • C&K Tactile Switch
  • Battery Connector format
  • Batteries
    • 3.0V Lithium CR123
    • 3.6V Lithium Thionyle Chloride 2600mAh
    • 3.6V Lithium Thionyle Chloride 3600mAh

License

Creative Commons Attribution-NonCommercial 4.0

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License
If you want to do commercial stuff with this project, please contact CH2i company so we can organize an simple agreement.

Misc

See TTN dedicated post and news and other projects on my blog