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--- loramessenger:project [2021/07/11 02:01] – neilhao
+++ loramessenger:project [2023/02/11 17:30] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Lora Messenger ======
+====== Compact Lora Messenger ======
-Neil Hao
+== - Optimized RF Design for Maximum Coverage ==
+[[http://uniteng.com/index.php/about-me/|Neil Hao]]
+Starts from 2021/Jul/09 to ~~LASTMOD~~ (Last Modification)
--Jul-2021
 ===== Overview =====
-This project aims to design a Lora Messenger which does not depend on Internet or Cellular network. In other words, users can chat with others by using this credit card size Lora device and a smartphone with Bluetooth without Internet and Cellular network.
+This project aims to design a credit card size Lora Messenger which does not depend on Internet or Cellular network. In other words, users can chat with others by using this credit card size Lora device and a smartphone with Bluetooth without Internet and Cellular network.
-For the hardware design, a high efficiency compact Lora PCB Antenna and an ultra-low noise figure amplifier had been designed to maximum the communication range.
+For the hardware design, a high efficiency compact Lora PCB Antenna and an ultra-low noise figure amplifier had been designed for maximum the communication range.
 For the software design, a simple Lora half duplex communication protocol had been implemented by about 600 lines of C++ code.
@@ Line 15: / Line 18: @@
   - Command Parser for executing user commands through Bluetooth.
-The coverage of this credit card size Lora device was tested. In the experiment (TX:14dBm, Freq:915Mhz, Spreading Factor:12), 1500m communication distance had been tested, no timeout or re-transmitting occurred.  According to the link budget, this system could reach far further than 1500m.
+The coverage of this credit card size Lora device was tested in the urban area. In the experiment (TX:14dBm, Freq:915Mhz, Spreading Factor:12), 1500m communication distance had been tested, no timeout or re-transmitting occurred.  According to the link budget, this system could reach far further than 1500m.
+[[https://www.youtube.com/watch?v=Rsd4tXtQQUE|Demo Video (YouTube)]]
+----
-[[https://www.youtube.com/watch?v=Rsd4tXtQQUE|Demo Video]]
 ===== Hardware Design =====
@@ Line 40: / Line 47: @@
-For the LNA which was designed based on SiGe NPN RF Transistor, it performs not only acting as a LNA but also as **Band pass filter**, **RF power limiter** and **impedance matching circuit**.
+For the LNA which was designed based on SiGe NPN RF Transistor (Q2 in the {{ :loramessenger:lora_messenger_schematics.pdf |}}), it performs not only acting as a LNA but also as **Band pass filter**, **RF power limiter** and **impedance matching circuit**.
 According to the EM simulation of the SX1276 official demo board:
@@ Line 71: / Line 78: @@
 {{ :loramessenger:lora_pcb_antenna_xy.png?direct&400 |}}
 XY Plane
+----
 ===== Software Design =====
 |Evaluation Firmware|{{ :loramessenger:lora_esp32_evaluation_firmware.zip |}}|Version: 08 Jul 2021|
+|Android App | [[https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&hl=en_US&gl=US|Serial Bluetooth Terminal]] |Retrieved Jul 11, 2021|
 ==== ESP32 PIN Assignments ====
 ^ Description      ^ PIN        ^
@@ Line 124: / Line 135: @@
 {{ :loramessenger:lora_receiving_process.png?direct |}}
 Note: Lora Receiving Process will be called consecutively.
+----
 ===== Resource =====
 |Schematics|{{ :loramessenger:lora_messenger_schematics.pdf |}}|Version: 25 May 2021|
@@ Line 129: / Line 142: @@
 |Note| PCB substrate: FR4|Thickness: 1.6mm|
 |Evaluation Firmware|{{ :loramessenger:lora_esp32_evaluation_firmware.zip |}}|Version: 08 Jul 2021|
+|Android App | [[https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&hl=en_US&gl=US|Serial Bluetooth Terminal]] |Retrieved Jul 11, 2021|
+----
 ===== Reference =====
 [1] Richard Wallace. Design Note DN024: Monopole PCB Antenna with Single or Dual Band Option . Retrieved Jul 11, 2021, from https://www.ti.com/lit/an/swra227e/swra227e.pdf?ts=1625872783255