Bluepad32 support for Arduino and CircuitPython

It is now possible to use Bluetooth gamepads both in Arduino and CircuitPython projects.

This means that you can use your PlayStation (PS3, PS4, PS5), Nintendo (Wii, Wii U, Switch) and Xbox One S gamepads in your electronics project: control a robot, home-automation, video games, etc… everything controlled from your favorite gamepad.

The catch is that not every Arduino or CircuitPython boards are supported. In fact, only a few of them are supported.

For Arduino, the boards that have the NINA-W10x (ESP32) co-processor are supported, like:

And similar for CircuitPython, the boards that have the AirLift (ESP32) co-processor are supported, like:

With the additional benefit that you can use any CircuitPython board by attaching the stand-alone AirLift module:

How does the co-processor work

Before describing how Bluepad32 works, it is better to first describe how WiFi works on NINA and AirLift co-processors (ESP32).

Both Arduino and CircuitPython use the co-processor mostly as WiFi modules. In order to use WiFi, you would use:

These two libraries (WiFiNINA and ESP32SPI) have the same functionality. In fact they are compatible. The only difference is that WiFININA is written in C++ , and ESP32SPI in Python.

The co-processor (ESP32) comes pre-flashed with the Arduino NINA firmware.

The ESP32 (A) connects to the internet using WiFi. And then sends the data back to the main processor (B). It uses a protocol that has some predefined messages like:

  • Open HTTP connection and get data
  • Enumerate SSID networks
  • Connect to SSID network
  • etc.

How does Bluepad32 work

Now that we know how WiFi works, it is easier to explain how Bluepad32 works. Similar to WiFi, Bluepad32 has two main parts:

The gamepad connects to the ESP32 (A) using Bluetooth. And the ESP32 (A) sends the gamepad data to the main processor (B). It uses the same protocol used by the NINA firmware, but with some extended messages like:

  • Get gamepad data
  • Set rumble on gamepad
  • Set player LEDs on gamepad
  • etc.

Bluepad32 firmware has the following features:

Bluepad32 library has the following features:

How to use it in Arduino

Bluepad32 library is part of the official Arduino library registry, so, you can install like any other Arduino library:

Arduino IDE -> Tools -> Manage Libraries -> Search for “bluepad32” and install.

And it comes already with an example that shows how to use it:

Arduino IDE -> File -> Examples -> Bluepad32 -> Gamepad

To flash the Bluepad32 firmware in your Arduino board, please follow these instructions:

How to use it in CircuitPython

Bluepad32 library is part of the official CircuitPython Community Library Bundle. You can install it like any other CircuitPython library. Install circup and then do:

$ circup install bluepad32

This example shows how to use Bluepad32 library for CircuitPython:

And to flash the Bluepad32 firmware in your CircuitPython board, please follow these instructions:

NINA vs AirLift vs ESP32

NINA-W10x are ESP32 modules. They are similar in functionality to the ESP32-WROOM-32 modules. Although the NINA modules are built by u-blox, and not by Espressif (do not confuse a ESP32 module with the ESP32 chip).

u-blox, in addition to the NINA-W10x modules, makes other modules that are not ESP32-based. But for the sake of simplicity, in this article, when we mention “NINA”, we talk about the NINA ESP32-based modules.

The NINA modules come pre-flashed with the Arduino NINA firmware, and in order to talk to them, you use the the WiFiNINA library.

Makes sense, it is consistent:

AirLift modules, on the other hand, are ESP32-WROOM-32 modules. I guess “AirLift” was created as a marketing name. But what is confusing is that they come pre-flashed with a fork of the Arduino NINA firmware, and the library name is called ESP32SPI.

It is confusing:

(Adafruit, if you are reading, I’d rename them to “AirLift firmware”, and “AirLift library”).

Whether it is a NINA-W10x, an AirLift module or an ESP32-WROOM32, all of them have the ESP32 chip inside. And all of them can run the NINA firmware, or the Bluepad32 firmware, or mostly any other ESP32 firmware that are out there.

So, if all of them are ESP32-based, and if WiFiNINA and ESP32SPI library are compatible, why did Adafruit fork Arduino’s NINA firmware? So far, the only incompatibility that I found, is that the MOSI pin (from SPI) is different.

GPIO 12 is strapping pin, and at boot time it is used internally by the ESP32. It seems that it was causing some interference with some modules.

And just because of that change (different MOSI pins) I needed to create a “Bluepad32 firmware for NINA” and a “Bluepad32 firmware for AirLift”.

Published by ricardoquesada

cocos2d, unicyclist, commodore 8-bit

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