Lora Relay

From MakerFabsWiki
Revision as of 07:50, 24 June 2020 by Charlin (talk | contribs) (Features)

Jump to: navigation, search


Lora Relay 01.jpg

Warning: If Lora Relay is used for controlling AC110V/AC220V Devices, be aware of safety.

This is a relay module that could be controlled by Lora, with max current 30A/240V. Based on RFM98W, it support max 4~5 km Lora communication.
This Lora relay module is preloaded Arduino Pro mini(3.3v 8M) bootloader and simple demo firmware Lora Relay V1.1, the users could freely change/update the firmware with Arduino IDE, with a common UART tool (Note that if there no DTR in your UART tool, you will need to press reset button to reset the controller Mega328P manually).
Lora Relay transceivers feature the LoRa long range modem that provides ultra-long range spread spectrum communication and high interference immunity.
Lora Relay offers bandwidth options ranging from 7.8125kHz to 500 kHz with spreading factors ranging from 6 to 12, there are three choices of the working frequency.
Item Lora Module working frequency
Lora Relay 433M RFM98W-433MHz/SX1278 433MHz
Lora Relay 868M RFM95W-868MHz 433MHzcommunication is established.
Lora Relay 915M RFM95W-915MHz 915MHz

Lora Soil 01A.jpg
Free ISM bands world Wide(come from TI)
Lora Relay based on the Arduino, users can program it with Arduino IDE, which is very easy especially suit for the none-programmers. There are also guide for users to learn how to create the first IoT project with this board, with which the starters can learn the hardware and programming skill quickly.

Required Materials

1. Lora Relay 2. Maduino Lora Radio 3. USB-to-UART tool 4. DC12V Adapter(at least 200mA) 5. microUSB Cable 6. PC

Lora Relay 02.jpg

This guides help you how to use a Maduino Lora Radio transmit messages to control the Lora Relay switch on or off. You can get Maduino Lora Radio from:

Lora Relay 03.jpg

This Lora Relay can be used to switch the AC bulb light on or off. We integrated the 30A current relay, which will give you a wide use for large current device. Notice: Maduino Lora Radio and the Lora Relay must have the same work frequency. Otherwise, it receive nothing from another.


• ATMEL Atmega328P: High Performance, Low Power Atmel®AVR® 8-Bit Microcontroller
• Speed Grade:20Mhz
• Flash:32Kbytes
• RAM: 2KBytes
• EEPROM: 1KBytes
• DC12V input
• Max Switch current:30A
• Max Switch Voltage: 250VAC
• Max Switch Power:7200VA
• Relay Contact form: SPDT
• Relay Coil Rated voltage:12V DC
• Relay Coil Rated current:75mA
• Relay Coil Rated resistance:160Ω±10%
• Relay Coil Pick-up Voltage: 75%Max
• Relay Coil Dropout Voltage: 10%Min
• Relay Coil Maximum voltage: 130%Max
• Mechanical Service life: 100,000 operations min. (at 1,800 operations/hour)
• Electrical Service life: 10,000,000(at 1,800 operations/hour)
• Temperature Range: -40C to 85C

Certified rating Lora Relay 04.jpg

Interface Function

Lora Soil 2.jpg
②J1:UART interface
④ISP: used for download bootloader
⑤RST:Reset button
⑥Lora Module

⑧Antenna interface


Required Materials

1. Lora Soil Moisture Sensor
2. Maduino Lora Radio
3. USB-to-UART tool
4. 2*AAA battery
5. microUSB Cable
6. PC

Lora Soil 03.jpg
System diagram
Notice: Maduino Lora Radio and the Lora Soil Moisture Sensor must have the same work frequency. Otherwise, it receive nothing from another.

Lora Soil Moisture Sensor requires a USB-to-UART tool to upload firmware to it, you can get it from:
Install the CP2102 driver from:

Hardware Connections

Lora Soil Moisture Sensor USB-to-UART Tool
3V3 3V3

Lora Soil 05.jpg

After a Arduino IDE installed, there is a default package to support Lora Soil Moisture Sensor(Arduino Zero ), From the top Arduino IDE menu, select Tools-> Board-> Arduino Pro or Pro Mini

Lora Soil 06.jpg

From the top Arduino IDE menu, select Tools-> Processor->Atmega328P(3.3V,8Mhz)
Lora Soil 07.jpg

After inserted the USB-to-UART tool to you PC, select the related Port. In my PC, there is COM7 that may different in your PC.
Lora Soil 08.jpg

Download the RadioHead file, click Add.ZIP.Library, select RadioHead.
Lora Soil 09.jpg

Open LoraTransmitterADCAHT10.ino, verify and upload the firmware to Lora Soil Moisture.
Modify the frequency macro according to your board is 433Mhz or 868Mhz or 915Mhz.
If your Lora board is 433MHz:

#define RF95_FREQ 433.0

If your Lora board is 868MHz:

#define RF95_FREQ 868.0

If your Lora board is 915MHz:

#define RF95_FREQ 915.0

Tips: Lora Soil Moisture designed as a product, so it not integrates the USB-to-UART on board. If you upload the firmware fails, press and hold the Reset button before upload the firmware. When the IDE shows below, then release the button that may helped to upload the firmware success. That’s we need a reset the MCU when upload the firmware.
Lora Soil 10A.jpg

Install the AAA*2 batteries and put the Lora Soil Moisture aside, now we need to make the Lora Radio Receiver.

2. Lora Radio Receiver.
Plug the Maduino Lora Radio to PC via microUSB cable.
Lora Soil 11A.jpg

Open the code LoraReceiver.ino
Select the Arduino Pro or Pro mini

Lora Soil 12A.jpg

Select ATmega328P(3.3V,8Mhz)

Lora Soil 13A.jpg

Verify and upload the firmware.

Lora Soil 14A.jpg

Lora Soil 15A.jpg


The Lora Soil Moisture will send messages via Lora Radio frequency. And the Maduino Lora Radio will receive the result and print them in the Serial Monitor.
Lora Soil 16.jpg

We can see it gets the air humidity and temperature and soil moisture from the Lora Soil Moisture Sensor.
Lora Soil 17.jpg


You can list your questions here or contact with support@makerfabs.com for technology support.