EspNowAudio

Project EspNowAudio
Status	Initializing
Contact	bertrik
Last Update	2020-03-15

What

The idea is to experiment a bit more with ESP now, in particular in combination with audio transfer.

Stuff to learn:

• ESP now broadcast mode: does it really work? https://github.com/espressif/ESP8266_NONOS_SDK/issues/8#issuecomment-419774432
• ESP now throughput: https://hackaday.io/project/166868-my-attempt-at-an-esp-now-mesh/log/166398-072419-maximum-transmission-throughput-of-esp-now
• ESP now packet loss when used continuously
• Audio over IP protocols, e.g. VBAN
• Possibility to transfer even ultrasonic audio?

Possible end result: A kind of zero-standby power intercom. When you press the button, an ESP8266 is powered up. It immediately starts transmitting audio from a digital I2S microphone over ESP now. The receiving end will probably be an ESP32, that receives the ESP now audio and converts into a standardized audio-over-ip protocol, e.g. VBAN.

Plans:

• build an Arduino playground project so I can access the API from the command line and play with it
• start with an ESP32 + INMP441

Related interesting stuff:

• https://www.hackster.io/julianfschroeter/esp32-voice-streamer-52bd7e
• ESP audio playback https://github.com/earlephilhower/ESP8266Audio
• VBAN specification https://www.vb-audio.com/Voicemeeter/VBANProtocol_Specifications.pdf

Result

ESP NOW broadcast just seems to work fine (not sure what prevented me from making it work earlier). I've set the WiFi channel to 1.

On the receiving side, I use an ESP32. On the sending side, I use an ESP8266:

• init the esp now library
• add the broadcast address as a peer
• send a message
• that's it!

References

• https://www.espressif.com/sites/default/files/documentation/esp-now_user_guide_en.pdf