EspNowSkip: Difference between revisions
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The ESP-now protocol is connectionless, you don't need to set up a session/get an ip-address to communicate between nodes. | The ESP-now protocol is connectionless, you don't need to set up a session/get an ip-address to communicate between nodes. | ||
== Hardware == | |||
The hardware is based on ESP8266, they are cheap and ubiquitous. | |||
The sender/slave/skip button is wired such that the actual physical button just wakes up the ESP8266. | |||
The receiver/master is connected to a raspberry pi or similar, receiving packets over ESP-Now, sending received data over serial to the raspberry pi. | |||
== Software == | |||
=== Source code === | |||
I plan to store source code here: | |||
* https://github.com/bertrik/EspNowSkip | |||
=== Proposed EspNowSkip protocol === | === Proposed EspNowSkip protocol === | ||
It could work something like this: | |||
* there are two roles: | * there are two roles: | ||
** a single central "master" node | ** a single central "master" node | ||
| Line 31: | Line 44: | ||
** the slave node keeps both wifi channel and MAC address in (emulated) EEPROM and goes back to sleep | ** the slave node keeps both wifi channel and MAC address in (emulated) EEPROM and goes back to sleep | ||
== References == | |||
* [https://esp-idf.readthedocs.io/en/latest/api-reference/wifi/esp_now.html Read-the-docs] about the low-level IDF ESP-Now API | * [https://esp-idf.readthedocs.io/en/latest/api-reference/wifi/esp_now.html Read-the-docs] about the low-level IDF ESP-Now API | ||
* [https://github.com/yoursunny/WifiEspNow WifiEspNow project on github] | * [https://github.com/yoursunny/WifiEspNow WifiEspNow project on github] | ||
Revision as of 21:08, 5 May 2018
| Project EspNowSkip | |
|---|---|
| 350px | |
| Muziekskipknop op basis van ESP-now protocol | |
| Status | Initializing |
| Contact | bertrik, jelly |
| Last Update | 2018-05-05 |
Introduction
This page is about using the ESP8266/ESP32 ESP-Now protocol in the music skip button.
A music skip button has some tricky requirements:
- you want it to react reasonably quickly, with little latency between pressing the button and skipping to the next song
- the skip button should be mobile, so it is battery powered and has to conserve power
The ESP-now protocol is connectionless, you don't need to set up a session/get an ip-address to communicate between nodes.
Hardware
The hardware is based on ESP8266, they are cheap and ubiquitous.
The sender/slave/skip button is wired such that the actual physical button just wakes up the ESP8266.
The receiver/master is connected to a raspberry pi or similar, receiving packets over ESP-Now, sending received data over serial to the raspberry pi.
Software
Source code
I plan to store source code here:
Proposed EspNowSkip protocol
It could work something like this:
- there are two roles:
- a single central "master" node
- one or more "slave" skip-buttons
- when the skip button is pressed, it wakes up from deep sleep and sends an ESP-now "SKIP" message to the last known channel and address of the central node
- if the skip button doesn't receive an ACK from the central node, it starts a kind of discovery to re-establish the channel and address of the central node
- the central node sets up an AP by name (e.g. "espnow-revspace") and broadcasts an ESP-now packet regularly (say every 10 seconds).
- the discovery procedure tries to find the central node by name, this AP name is the only thing that needs to be agreed upon in advance between master and slave code
- from the AP name, the slave node can determine the wifi channel to use
- from the AP broadcast packet, the slave node can determine the master MAC address to send to
- the slave node keeps both wifi channel and MAC address in (emulated) EEPROM and goes back to sleep
References
- Read-the-docs about the low-level IDF ESP-Now API
- WifiEspNow project on github