Perfecting The Open Source RC Controller

Over the last few months we’ve seen an influx of homebrew RC controllers come our way, and we’re certainly not complaining. While the prices of commercial RC transmitters are at an all-time low, and many of them can even run an open source firmware, there’s still nothing quite like building the thing yourself. How else are you going to get exactly what you want?

For this entry into the 2019 Hackaday Prize, [Vitor de Miranda Henrique] is working on his own version of the ultimate open source remote control. His design follows some of the trends we’ve already seen in terms of outward design and hardware expandability, but also branches off into some new territory with features such as dual integrated displays.

Why does your controller need two displays? The top 4.3 inch TFT is linked up to a 5.2 GHz video receiver, which makes it perfect for controlling vehicles in “first-person” view, such as drones. The lower screen is a 2.8 inch touch screen from Adafruit, which is intended to be used for navigating through menus and options once the firmware is fully fleshed out.

Powering the controller is a ESP32 and dual MCP23017 GPIO expanders to connect up to the array of input devices available to the user. The current iteration of the controller has ten switches, two encoders, some buttons, and a pair of scroll wheels for good measure. Oh, and of course there are a couple of joysticks in the mix as well. All the devices terminate at a custom PCB in the back of the controller which looks to make modifying and adding input devices simple and neat.

We’ve previously seen the Alpha V1, an open source controller with a fairly similar setup, albeit without the dual displays. If even that one is a bit more complex than you’d like, you can always just do it with an Arduino.

Blynk With Joy

Last time, I talked about how my storage situation and my cheap nature led me to build an RC joystick controller with a cell phone app and an ESP8266. The key to making this easy was to use the GUI builder called Blynk to make a user interface for an Android or Apple phone. Blynk can communicate with the ESP8266 and makes the project relatively simple.

ESP8266 and Arduino IDE

The ESP8266 Blynk code is straightforward. You do need to set up the Arduino IDE to build for the ESP8266. That can vary by board, but here’s the instructions for the board I was using (from Adafruit; see below).

adaesp

Depending on the type of ESP8266 device you are using, you may need a 3.3 V serial cable or some other means of getting the firmware into the device. For the Adafruit device I had, it has a 5 V-tolerant serial connection so a standard USB to serial dongle plugs right in. There’s also two switches on my device. To get into bootload mode, you have to push the one button down, hold it, and then press the reset button. Once you release the reset button you can release the other button. The red LED half-glows and the device is then waiting for a download.
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