audi-no
audi-no
0
Project description
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
