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ATMega328 LoRaWAN Node

From MakerVan Labs

Revision as of 21:29, 9 January 2021 by Severin (talk | contribs) (→‎Parts)
     
ATMega328 LoRaWAN Node

Release status: experimental [box doku]

Description A LoRaWAN node based on the ATMega328 and the RFM95 LoRa module.
Last Version  0.4 (2021-01-03)
Platform  ATMega328
License  CC BY-SA 4.0

The ATMega328 LoRaWAN Node is the successor of the ProMini LoRaWAN Node. As the ProMini version, it is powered by an ATMega328, running at 3.3V and 8Mhz, but instead of using an Arduino ProMini board, it uses a barebones ATMega328. This removes the issues of the ProMini board such as weird pin layout for the I2C pins, the always-on LED, and the power regulator. There have been some additional fixes to the ProMini Node board, such as:

  • Reordering the power pins so you can solder in screw connectors as well
  • Strain relief holes next to the power pins
  • Two mounting holes
  • No more voltage measurement for the 3.3V/Vcc bus, as this can be done internally on the ATMega

Parts

Note: Antenna and LoRaWAN module are dependent on the local frequency band used for LoRaWAN. The selected items are meant for 868Mhz, which is the frequency band for Europe

Part Partnumber Amount Source Notes
PCB ATMega328 LoRaWAN Node PCB v0.4 1 -
Microcontroller ATMega 328P-PU 1 Reichelt
IC socket 28pin 1 Reichelt
Quartz 8Mhz, HC49U-S 1 Reichelt
Resistor R4: 10k 0805 1 Reichelt
Capacitors C4, C5: 22pF 2 Reichelt
C6, C7: 100nF 2 Reichelt
Reset button SW1 1 Reichelt
Voltage regulator for >3.3V input
Voltage Regulator U3: 3.3V, LDO, TO-92 -> LP2950-3.3 1 Reichelt
Capacitor C2, C3: 4,7µF Elko, >16V 2 Reichelt
LoRa Modem section
Antenna 868Mhz SMA 1 DigiKey
Amazon US
Amazon DE
AliExpress
Antenna Connector SMA Edge mount 1 DigiKey
Amazon US
Amazon DE
AliExpress
u.FL surface mount DigiKey To connect an SMA antenna, you will need a matching pigtail
LoRa Module RFM95 868Mhz DigiKey
Amazon US
Amazon DE
Input voltage measurement
MOSFET Q1: BSS 84 1 Reichelt
Resistors R1: 100k 0805 1 Reichelt
R2: 150k 0805 1 Reichelt max input voltage for this R2/R3 combination: 16V
R3: 10k 0805 1 Reichelt
Capacitor C1: 100nF 1 Reichelt
Connectors
ISP J1: 2x3, 2.54mm 1 Reihelt 2x4 connector is much cheaper than 2x3, but you can simply cut off one section
Pin headers P3, P5, P6, P9, P10 (many pins) Reichelt Just get one long row, and cut off those you need
Screw terminals (Power In) P2 (outer pins): 2 pole, 5.08mm 1 Reichelt only if using voltage regulator
Misc
Battery Holder 2x AA AliExpress
Case Abzweigdose 75x75 Hardware store [1], [2]

License

  • Licensed under Creative Commons Attribution-ShareAlike 4.0 Unported License (CC BY-SA 4.0)