Today we will look at the remote control unit for the Robotic Toy Car – Part 6.

The project is close to being completed, and as such, there are quite a lot of final things that need to be taken care of.

One of these will definitely be the final coding, which I will release in the final part of the project, so with that in mind, let us take a look at the remote control unit.

Remote Control Unit, designed to be used with ESP-Now

I have decided to do something completely different from standard remote control units, being that I will use ESP-Now, a protocol developed by Espressif.

ESP-Now runs on the Wifi hardware of the ESP8266 or ESP32 and is basically a peer-to-peer protocol, that does not require Wifi but can co-exist with it on the same device. Outdoors, ESP-Now has a range of about 100m, which should work very well for my intended use.

The Remote control, as designed, will have 4 dedicated buttons: forward, reverse, left and right, divided into two groups to make two-handed control easier, similar to a standard game controller. No input on either of the two groups will result in stopping the vehicle, in the case of forwards and backwards, and centring the steering, in the case of the left-right axis.

a 3D Rendered Image of the PCB, motion axis on SW1 and SW2, steering axis on SW3 and SW4

As I always try to make my designs somewhat reusable for other purposes, I have also broken out most of the unused GPIO pins to header pins, with also adding a jumper on GPIO16 to make deep-sleep wakeup mode possible., You can also re-use the switch pins for other purposes, just remember to first remove the 10k pull-up resistors at R14, R15, R16, and R17…

SW4 -> R16 , SW4 = GPIO4

SW3 -> R17 , SW3 = GPIO5

SW2 -> R15 , SW2 = GPIO13

SW1 -> R14 , SW1 = GPIO12

GPIO16 can be reused as well, just remove the jumper, but remember that it is pulled up through a LED and a 470ohm resistor…

There is no USB-to-serial converter onboard, I have been having quite a lot of headaches with them over the last few months, with almost all CH340G chips that I have purchased, being fake, or dead-on arrivals that don’t work… Sending them back to the suppliers, unfortunately, results in unpleasantries, because even placing them in verified working circuits, still proves them to be not working… This is however not an issue, as it is quite easy to upload the board with an external adapter.

The Schematic

Schematic Diagram