Merge remote-tracking branch 'refs/remotes/origin/master'

Author: sh123

README.md

@@ -3,9 +3,9 @@
 ## Introduction
 ⚠ **Please note that this device is experimental and lacks any form of certification. The author holds no responsibility for any fines incurred due to spectrum misuse, legal violations, or damages caused during its use. As with any experimental project, it is essential that you fully understand what you are doing and use it at your own risk.**
 
-This project is a hobby/amateur/toy/educational radio ESP32 based LoRa/FSK Codec2/OPUS DV 3d printed handheld trasceiver a.k.a. walkie-talkie, which is using 1W/2W E22-400M30S/E22-400M33S (SX1268) radio module (UHF, 70cm band) or optionally 100mW RA-01/RA-02 (SX1278) module. 
+This project is a hobby/amateur/toy/educational radio ESP32 based LoRa/FSK Codec2/OPUS DV 3d printed handheld trasceiver a.k.a. walkie-talkie, which is using 1W/2W `E22-400M30S/E22-400M33S` (SX1268) radio module (UHF, 70cm band) or optionally 100mW `RA-01/RA-02` (SX1278) module. In theory, it could also be used with `E22-868M30S/E22-900M30S` (SX1262) modules (UHF, 868/915 MHz), but not tested.
 
-It functions like a standard FM walkie-talkie and, for simplicity, does not utilize any communication protocol. Instead, it transmits audio codec frames using pre-configured digital radio modulation.
+It functions like a standard FM walkie-talkie and, for simplicity and traffic optimization, does not utilize any communication protocol. Instead, it transmits audio codec frames (DV) using pre-configured digital radio modulation, such as LoRA or FSK. There are ideas to add voice over AX.25 and perhaps M17 protocol support in the future.
 
 Overall components cost for this project is about 15-20$.
 
@@ -29,12 +29,42 @@ Supports next features:
 - Output power tunable from settings from ~1mW (for ISM toy usage) up to 2W (for amateur radio experiments)
 - Experimental no warranty privacy option for ISM low power usage (⚠ **check your country regulations if it is allowed by the ISM band plan before experimenting as it might be illegal in some countries**), it is based on [ChaCha20-Poly1305](https://en.wikipedia.org/wiki/ChaCha20-Poly1305) stream cypher provided by [rwheater/Crypto](https://github.com/rweather/arduinolibs) library, it is comparable to AES256, uses 256 bits key, provides message authentication, but should have lower CPU requirements and power usage.
 
+Planned features/ideas:
+- Frequency split repeater mode, where two transceivers will be linked using espnow, so one will receive voice on RX frequency and then send packet using espnow to second transmitter which will receive packet using espnow and re-transmit it on TX frequency, this way receiver and transmitter could be positioned further apart with separate antennas thus eliminating need for duplexer
+- Bluetooth headset pairing to use with hands free, so can use headset instead of i2s speaker/mic when needed
+- Voice over AX.25, so meta data such as callsign could be included and visible on the other end
+- M17 protocol support
+
 ## Build instructions
 - Modify `include/config.h` if needed
 - Install platformio
 - Build with platformio
 - Upload with platformio
 
+## BOM
+Bill of materials (BOM) for the new board constuction (credits to n0p and his club members for collecting it)
+```
+ESP-WROOM32 30pin - https://es.aliexpress.com/item/1005005953505528.html
+Modem LoRa E22-400M30S (SX1268) - https://es.aliexpress.com/item/1005003122961059.html
+I2S speaker module MAX98357A - https://es.aliexpress.com/item/1005005383121121.html
+4ohm 3w speaker (40mm diameter) - https://es.aliexpress.com/item/1005006684947554.html
+I2S microphone INMP441 - https://es.aliexpress.com/item/1005007889064664.html
+Rotary encoder with push button - https://es.aliexpress.com/item/1005008091948369.html 
+Small OLED display SSD1306 128×32 - https://es.aliexpress.com/item/1005008096924594.html
+Uses combined charge + 5v boost controller - https://es.aliexpress.com/item/1005008657948784.html
+
+18650 Cell
+Botón switch tactile SKHH angled - https://es.aliexpress.com/item/1005005369415986.html
+SMA-J-P-X-ST-EM1 Edgemount - https://es.aliexpress.com/item/10000000835065.html
+R1 - 100k 0603 - https://es.aliexpress.com/item/1005005677654015.html
+R2-R7 - 10k 0603 - https://es.aliexpress.com/item/1005005677654015.html
+C1, C3-C8, C10, C11 - 100nF 0603 - https://es.aliexpress.com/item/32371454429.html
+C2 - Elec 100uF SMD 3×5,3 - https://es.aliexpress.com/item/1005006724593986.html
+C9 - 47uF Radial D4 mm P2 mm - https://es.aliexpress.com/item/1005005022177024.html
+
+GPS - OPTIONAL - UNSUPPORTED ON WALKIE FW - CONFLICTS WITH ON BOARD SERIAL PORT PROGRAMMER - https://es.aliexpress.com/item/1005008733474270.html
+```
+
 ## Pictures
 
 Two fully 3d printed prototypes were built based on `esp32_loraprs` modem board.