Configuring the Firmware using Bluetooth for ESP32

Quick access:

IMPORTANT: Cale Android App. and Arduino ESP32 bluetooth Firmware is not anymore maintained in favour of ESP-Rainmaker.

Please use the IDF Firmware and the Rainmaker branch to send your WiFi credential to your display boards. We are currently in the process of reshaping and making the Firmware configuration easier. The Android app is now oficially the default way to set up your display. But we will always keep the possibility to have also a version that uses a hardcoded C configuration since there are many use cases where the user does not have Android, or just wants to have a configuration like this per se, keeping in mind that ESP8266 has no bluetooth.



Configuring a Screen and WiFi

In 3 steps make a demo Screen

  1. Logged in CALE Admin section "WiFi"
    Add 2 access points where the display can get online (ex. home WiFi, mobile hotspot)
  2. Add an API
    Just add your Google Calendar or to start a HTML API with an image or title as content
  3. On the Screen config, select what WiFis you are going to use
    This will generate a JSON configuration string.
    In Screen Content partials add the API that you created in point 2

Send this configuration with Bluetooth to your ESP32 display

Configuring the firmware boils down to 2 steps:

  1. Install the Android app
    As a first step connect it with CALE scanning the QR code.
    In the Backend: User Api QR code
  2. Select the Screen and the ESP32 Bluetooth target to configure in the app
    Check that the JSON config is there and Send it to your device
Make sure that before point 3, the display is connected, and waiting for Bluetooth configuration.

CALE Android application


Please download the APK with your mobile browser and give it permissions:

CALE Android in Play store

CALE Android APK Releases Please use this version to get the latest APK if your version is < 1.1.3 and it does not come automatically from the Play store

CALE Android app Step 1: Connect App with cale.es scanning QR CALE Android app Step 2: Select your Screen CALE Android app Step 3: With bluetooth open select ESP32 CALE Android app Step 4: Send and DONE! Your Eink should refresh

Repository with the Bluetooth version of the Firmware

https://github.com/martinberlin/eink-calendar - master branch

Ready to be be configured using CALE ANDROID APP
  1. Receives 2 WiFi APS, screen_url and bearer token
  2. Saves this on preferences for next restart

How to reset preferences

 Once WiFi is connected, Bluetooth is disconnected, since the ESP32 uses the same Antenna for both. So if we want a reset method, you have two options, either get out of your WiFi area with your Epaper display. Or if you want to reset it because you are compiling the Firmware for someone else, you can do a preferences.clear() 
     // Uncomment to force delete preferences
     // preferences.clear();
But don't forget to leave it commented on the final compilation. Otherwise it will never save the WiFi credentials.


Sending the Config using Bluetooth

To connect the Android up just scan the QR Code provided in the Backend (Top menu User Api QR) The App will take care of listing your Screens and prepare the JSON configuration to send to the ESP32.
As a preamble, to make sure you have the essential things set up, you can log in the CALE BACKEND and check that:

  1. Use the WiFi section you need at least one WiFi access point so your Epaper can get online (Ex. home/office)
  2. Go to Screen and on the list click on Config.
  3. The Bluetooth tab is the default and in a mobile request will come at the top.
  4. First two WiFi access points will be preselected, this is already send by the Android App automatically, no need to copy and paste
So to summarize, you need a Screen configured to use a display, and to have at least one WiFi access point so it can get online.

CALE Bluetooth config After the last update to the Android app is now easier to configure. Provided the QR is already scanned this is the way to set up one new Epaper display:
  • Start the Eink Display, in the CALE ANDROID APP select the Bluetooth starting with CALE_*
  • Accept Android pair request
  • Click Send Config in the last step

That's it! The Epaper display should restart, connect to WiFi, and render your Screen.

Config optional settings

If you want to use an ESP32 Tinypico as the Epaper display controller, we used unexpected maker library to get the minimal consumption. Please uncomment this define in Config.h to lower the deepsleep consumption to 0.08 mA/hour:

        //#define TINYPICO

Bluetooth user flow

CALE user flow for Bluetooth config