RisingHF’s RHF76-052 module is an economical choice to connect with KotahiNet’s network. It is a transceiver and therefore needs the MCU to run the LoRaWAN network stack. A quick way to evaluate the module and test connect with KotahiNet is to use their standalone RHF3M076 which is a USB LoRaWAN AT Modem that can be plugged into a computer.
In small quantities, the RHF76-052 is US$16 (about $24) and RHF3M076 is US$ 43 (about $63).
Connect the RHF3M076 to a PC using a USB cable. It should set up automatically as a serial device. Use any serial terminal to connect. Settings are default- 9600 bps, 8 bits, no parity, 1 Stop bit, no flow control. All commands need to be terminated with <CR><LF> and any replies will also be terminated by the same sequence. Turn screen echo on.
Configuring the RHF3M076 uses AT commands and is somewhat similar to configuring the Microchip RN2483 with mac commands.
If you find that entering AT into the serial terminal immediately leads to a response “+INFO: Input timeout, start parse” making it impossible to enter any AT commands, type AT+UART=Timeout,0 in a notepad and then copy and paste that into the serial terminal. This disables the timeouts.
// Disable timeouts
+INFO: Input timeout, start parse
+UART: TIMEOUT is disabled
// Set Device EUI. Note this is for testing only. Contact KotahiNet for your own credentials
+ID: DevEui, 11:11:aa:aa:00:00:00:aa
// Set App EUI. Note this is for testing only. Contact KotahiNet for your own credentials
+ID: AppEui, be:7a:00:aa:be:7a:00:aa
// Set Application Key. Note this is for testing only. Contact KotahiNet for your own credentials
+KEY: APPKEY F7 70 E4 72 95 4F C4 F5 A4 FA F2 50 AA FD C8 14
// Configure channel 0. Default data rates are OK.
// Configure channel 1
// Configure channel 2
// Configure channel 3
// Configure channel 4
// Configure channel 5
// Configure channel 6
// Configure channel 7
// Configure channel 8. Set bandwidth to 250 kHz, Spreading Factor 7
// Set RX Window 2
// Set transmission power to maximum
// Set Adaptive Data Rate on
// Set join mode to Over The Air Activation
// Connect to network
+JOIN: NORMAL, count 1, 0s, 0s
+JOIN: Network joined
+JOIN: NetID 4C5254 DevAddr a8:19:32:27
// Send confirmed hexadecimal test message
+CMSGHEX: Start LoRaWAN transaction
+CMSGHEX: TX “12 34 56 ”
+CMSGHEX: Wait ACK
+CMSGHEX: ACK Received
+CMSGHEX: RXWIN1, RSSI -109, SNR 1.75