Please visit our campaign XRange (RF module sx1272 with STM32L152)   at Indiegogo.com 

Last year our team at netblocks worked with several FR modules from different manufactures to accomplish a home automation project. But we had not been satisfied with the performance of RF part because they cannot achieve  the communication distance that we needed. When we had learned about the new LoRa™ technology from Semtech, we decided to try it. At that time there was only one kit available with LoRa™ SX1272DVK1CAS-ND but the price of the kit ($689) was above our budget, so we decided to build it ourself. We downloaded design files for SX1272RF1BAS-ND and produced the PCB board.

Next we spent three weeks to order and collect all parts for the board. We connected the STM32LVDISCOVERY to SX1272RF1BAS.

Here is the result:

Schematic of the connection between the boards:

sx1272-discovery – Schematic

Connection description:

	SX1272 PCB conector	STM32LVDISCOVERY
1	SCK	PA5
2	3.3V	3.3V
3	MOSI	PA7
4	GND	GND
5	DIO1	PB1
6	DIO3	PB4
7	NSS	PA4
8	MISO	PA6
9	DIO5	PB6
10	RESET	PB8
11	DIO4	PB5
12	DIO0	PB0
17	DIO2	PB2
20	FEM_CTX	PB7
22	3.3V	3.3V

 

Source code can be downloaded at GitHub:

Conclusion:

The performance of LoRa transceiver exceeded our expectations.

The results are over 12km of usable range in rural environment, connection from the sixth floor of solid building to the basement ,  over 1km in dense urban environment.

We at netblocks decided that LoRa RF technology adds powerful tool which can satisfy wide range RF communication needs of many designers of embedded systems.

We also designed a RF communication module called XRange based on SX1272 and STM32L152.

You can contribute to our project at Indiegogo

When the XRange is ready we will publish the schematic of module  and source code of the firmware, so you can easy reuse the LoRa technology in your next project.

For more information please check the EEVblog

NetBlocks team.