ESP8266 based Spotify currently playing track display

This is an ESP8266 based Spotify client built with 256x64 (or 128x64) OLED display. The main purpose is to retrieve information about the currently playing track and show it on the display. ESP8266 connects directly to Spotify, so no third-party proxy services are used.

Application uses Spotify Web API and implements OAuth 2.0a authorization as described here. Currently-playing endpoint is used to retrieve the track information and play, pause and next endpoints are used to control the playback.

Unicode is supported. Glyphs for all characters found in Arial Unicode MS font are embedded in the binary. The glyphs are regular and bold variants with the sizes of 10 and 13.

Building the hardware/software

There are two options for hardware: either a custom build with SSD1322 based 256x64 OLED or a Wemos Nodemcu 1.3" 128x64 OLED board. For the custom hardware please see schematics and instructions from my other project ESP8266 Twitter Client. If the Wemos board is used, please uncomment WEMOS_NODEMCU_OLED_BOARD define in hwconf.h file.

Please see the instructions for software building and binary flashing from the Twitter Client project.

Usage

Device settings can be changed through the serial interface (921600/8-N-1). The following syntax should be used:

parameter:value<CR>

At least the following parameters must be set by the user:

• ssid - WiFi SSID
• pass - WiFi password
• client_id - Spotify app client id
• client_secret - Spotify app client secret key
• auth_code - Spotify app authorization code

In order to obtain Spotify app client id and secret key, user must create a new Spotify app with her own account:

1. Go to https://developer.spotify.com/my-applications/#!/applications/create
2. Fill the form. Set Redirect URIs to http://httpbin.org/anything and other fields to values of your choice.
3. When the app is created, copy Client ID and Client Secret values into the device.

Next, we need to obtain the authorization code:

1. In the following URL replace <client_id> with your app client id and open the URL with your browser. https://accounts.spotify.com/authorize/?client_id=<client_id>&response_type=code&redirect_uri=http%3A%2F%2Fhttpbin.org%2Fanything&scope=user-read-private%20user-read-currently-playing%20user-read-playback-state%20user-modify-playback-state
2. Authorize the app and you will be redirected to httpbin.org/anything.
3. Copy the code (without quotes) into the device. The code can also be copied from browser address bar.

The device should now be able to login to Spotify with the user's account and display the currently playing track. By default the device will poll Spotify server every 10 seconds. Poll interval can be changed with poll parameter (value in seconds). Please see the config.c file for additional supported parameters.

Custom hardware contains two buttons: one for pause and resume the playback and another for skip to the next track. On Wemos board there's only one button: short press for pause/resume and long press for skip to next track.

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