Websockets!

connection

(normal)

esp32 <--- wifi ---> Wifi AP <--- network ---> computer C <--- data transfer via websocket protocol ---> webpage websocket server client client wifi server client

(setup) esp32 <--- wifi ---> computer webserver client

features ideally

• real time data to webpage via websockets (stream or packet?)
• fast fourier transforms to get frequency
• wifi setup and settings storage in eeprom
• multiple clients?
• data storage / file save?

what works currently

• esp connects to wifi AP
• esp can be websocket server
• esp sends accelerometer data every second to newest client asas

stuff for esp32

https://randomnerdtutorials.com/esp32-wi-fi-manager-asyncwebserver/ <- manage wifi with creds stored in eeprom https://www.mischianti.org/2020/06/04/esp32-integrated-spiffs-filesystem-part-2/ <- you have 4 mb https://randomnerdtutorials.com/esp32-web-server-microsd-card/ <- but you can serve files off sd card [done] me-no-dev/ESPAsyncWebServer#1085 <- manual fix for ESPAsyncWebServer (arduino update broke it :/) [done] https://makeradvisor.com/tools/sd-card-module/ <- cheap af reader https://lastminuteengineers.com/handling-esp32-gpio-interrupts-tutorial/ <- interrupts might be useful https://forum.arduino.cc/t/using-millis-for-timing-a-beginners-guide/483573 <- use this instead of delay! [done] https://github.com/me-no-dev/ESPAsyncWebServer#async-websocket-event <- use integrated websocket event from ESPAsyncWebServer! [done] me-no-dev/ESPAsyncWebServer#504 <- oh no :( can only send 15 readings over websocket per second...

TODO

• use integrated websocket thing in ESPAsyncWebServer to hopefully speed things up. currently rather slow [done]
  • still slow, max messages per sec is about 15 for esp32, fix:
    • batch messages together (may fill heap fast)
    • events? (not bi-directional...)
• read wifi connection data from sd card
• rgb status led for charge, wifi conn, ...