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A few thoughts: Events at work would be way easier with wireless comms. Unfortunately the boss will never go for a commercial system (reasonably so) It would also be a neat project to show off when applying for internships. And a distraction from studying for exams (not necessarily a good thing tbh) Some goals / design requirements: Cost | $10ish per unit, at scale. ----------------------------------------------------------------------------------------------------------------------- Range | 500 - 800m LOS. Depending on the need for certification obvs, this is OSHW & I'm a student. | The system should function in a crowded room & I'd expect coverage around the ground floor of | where I live / work. ----------------------------------------------------------------------------------------------------------------------- Protocol | TBD. Some sort of mesh system would be a good idea. A chain topology is not suitable, as it makes | the whole thing very fragile. [2] ----------------------------------------------------------------------------------------------------------------------- Processor | TBD And some things that have already been decided: Power source | LiPoly battery or similar. Minimum 8hr battery life. ----------------------------------------------------------------------------------------------------------------------- Connectivity | USB C charging built in. Exposed serial port or JTAG for programming. Perhaps both? Should use | standard 10pin header for use with a BlackMagic probe. RJ45 could be an option for serial. [1] | | Headset, Microphone & PTT on 3.5mm jacks. Mini XLR could be explored? ----------------------------------------------------------------------------------------------------------------------- UI / UX | Ease of use is a top priority. The whole thing should be set and forget. | An OLED display and a rotary encoder / pushbutton can do a lot. | Must haves: | Battery indicator w dedicated pushbutton | A way to display the band & connection strength if that's important to the protocol chosen | "PTT active" display. Control on the unit as well as through the external connector [1]: Future things to explore: Wired Networking? Could be of interest for wider situations or RF noisy enviroments. Possiblity of a base station for future expansion. I have an RPi Pico with a WizNet SPI-10/100 ethernet chip on it that could be handy [2] I'm taliking out my ass here. No idea what I'm going to use but it'll come down to the chipset chosen / cost / range / licensing / etc etc etc Possible architecture: ----------- ----------- -------- | TX & RX | ------ ? ------| -------------------- |----- SPI ----- | W51000s | --- ETHERNET --- | RJ45 | ----------- | | | | ----------- -------- |----------- | | -----------| | RP2040 | |----------- | | -----------| -------------- ----------- | | | | ---------------- | MICROPHONE | ------ | CODEC | ------ ? ------| -------------------- |--------------- | PUSH TO TALK | -------------- ----------- | | | ---------------- | | | | ---------------- | | | | | AUDIO OUTPUT | ----------| ----------------- -------- | ---------- -------- ---------------- | 10 PIN HEADER | -------- | JTAG | | | SERIAL | --- RS-485? --- | RJ45 | ----------------- -------- | ---------- -------- | |----------------------------- USB 1.1 ----------------------------| | --------- ------------------- ----------- -------------- | USB-C | ----- | BATTERY CHARGER | ----- | BATTERY | ----- | REGULATORS | --------- ------------------- ----------- -------------- Part table: RADIO | | BATTERY CHARGER | ----------------------------------------------------------------------------------------------------------------------- PROCESSOR | RP2040 [3] | BATTERY | ----------------------------------------------------------------------------------------------------------------------- MICROPHONE | | REGULATORS | ----------------------------------------------------------------------------------------------------------------------- AUDIO CODEC | | | ----------------------------------------------------------------------------------------------------------------------- ETHERNET INTERFACE | WIZNet W5100S [4] | | ----------------------------------------------------------------------------------------------------------------------- [3] I'm choosing this processor because I have a devboard for it sitting on my desk :) [4] The RP2040 dev board is a W5100S-EVB-Pico by WIZNet which has this IC on it. It's an SPI connected 10/100 Ethernet controller / MAC
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