%% Generated by Sphinx. \def\sphinxdocclass{report} \documentclass[letterpaper,10pt,english]{sphinxmanual} \ifdefined\pdfpxdimen \let\sphinxpxdimen\pdfpxdimen\else\newdimen\sphinxpxdimen \fi \sphinxpxdimen=.75bp\relax \ifdefined\pdfimageresolution \pdfimageresolution= \numexpr \dimexpr1in\relax/\sphinxpxdimen\relax \fi %% let collapsible pdf bookmarks panel have high depth per default \PassOptionsToPackage{bookmarksdepth=5}{hyperref} \PassOptionsToPackage{booktabs}{sphinx} \PassOptionsToPackage{colorrows}{sphinx} \PassOptionsToPackage{warn}{textcomp} \usepackage[utf8]{inputenc} \ifdefined\DeclareUnicodeCharacter % support both utf8 and utf8x syntaxes \ifdefined\DeclareUnicodeCharacterAsOptional \def\sphinxDUC#1{\DeclareUnicodeCharacter{"#1}} \else \let\sphinxDUC\DeclareUnicodeCharacter \fi \sphinxDUC{00A0}{\nobreakspace} \sphinxDUC{2500}{\sphinxunichar{2500}} \sphinxDUC{2502}{\sphinxunichar{2502}} \sphinxDUC{2514}{\sphinxunichar{2514}} \sphinxDUC{251C}{\sphinxunichar{251C}} \sphinxDUC{2572}{\textbackslash} \fi \usepackage{cmap} \usepackage[T1]{fontenc} \usepackage{amsmath,amssymb,amstext} \usepackage{babel} \usepackage{tgtermes} \usepackage{tgheros} \renewcommand{\ttdefault}{txtt} \usepackage[Bjarne]{fncychap} \usepackage{sphinx} \fvset{fontsize=auto} \usepackage{geometry} % Include hyperref last. \usepackage{hyperref} % Fix anchor placement for figures with captions. \usepackage{hypcap}% it must be loaded after hyperref. % Set up styles of URL: it should be placed after hyperref. \urlstyle{same} \usepackage{sphinxmessages} \setcounter{tocdepth}{2} \title{Byte Rider} \date{Jul 19, 2025} \release{06\sphinxhyphen{}2025} \author{Alexander B} \newcommand{\sphinxlogo}{\vbox{}} \renewcommand{\releasename}{Release} \makeindex \begin{document} \ifdefined\shorthandoff \ifnum\catcode`\=\string=\active\shorthandoff{=}\fi \ifnum\catcode`\"=\active\shorthandoff{"}\fi \fi \pagestyle{empty} \sphinxmaketitle \pagestyle{plain} \sphinxtableofcontents \pagestyle{normal} \phantomsection\label{\detokenize{index::doc}} \noindent\sphinxincludegraphics{{ESP-IDF_Robot}.jpg} \sphinxstepscope \chapter{OVERVIEW} \label{\detokenize{intro:overview}}\label{\detokenize{intro::doc}} \sphinxAtStartPar At the heart of this project is a customizable remote\sphinxhyphen{}controlled car that responds to real\sphinxhyphen{}time control inputs, capable of handling speed adjustments, directional changes, and even extended features like lights or sensors. The foundational setup uses ESP\sphinxhyphen{}NOW for transmitter and receiver devices, allowing you to wirelessly guide the car’s behaviour. While the design and physical appearance of the RC car can vary wildly depending on your creativity and available hardware, the control system remains elegantly efficient. To facilitate wireless communication between devices, the system employs ESP\sphinxhyphen{}NOW , which is a lightweight and connection\sphinxhyphen{}free protocol ideal for fast, low\sphinxhyphen{}latency data transmission between ESP32 microcontrollers. Though ESP\sphinxhyphen{}NOW is used under the hood, the spotlight remains on the RC car itself. \sphinxAtStartPar An ESP\sphinxhyphen{}NOW\sphinxhyphen{}based remote controller sends control data wirelessly using the ESP\sphinxhyphen{}NOW protocol to the remote\sphinxhyphen{}controlled car. ESP\sphinxhyphen{}NOW enables fast and efficient communication between ESP32 devices without the need for a Wi\sphinxhyphen{}Fi router, network, or pairing. The provided tutorial demonstrates a functional setup where a transmitter sends data to a receiver to define the car’s speed and direction, forming the core communication loop. While the baseline implementation focuses on movement, additional features like lights, sensors, or telemetry can easily be integrated by expanding the source code. This modular design gives users the freedom to customize both the appearance and behaviour of their RC car, resulting in endless creative possibilities. \section{ABSTRACT} \label{\detokenize{intro:abstract}} \sphinxAtStartPar To enable real\sphinxhyphen{}time remote operation of the RC car, the system translates joystick x\sphinxhyphen{} and y\sphinxhyphen{} axis inputs into PWM (Pulse Width Modulation) signals that control the DC motors. These PWM values are stored in a predefined data structure, which is then transmitted wirelessly using ESP\sphinxhyphen{}NOW — a low\sphinxhyphen{}latency, connectionless communication protocol developed by Espressif. Both the transmitter and receiver modules are based on ESP32\sphinxhyphen{}C3 microcontrollers. \sphinxAtStartPar On the transmitter side, the joystick’s X and Y coordinates are continuously monitored and converted into PWM parameters. These values are packed into the data structure and sent via ESP\sphinxhyphen{}NOW to the receiver. \sphinxAtStartPar The receiver module listens for incoming ESP\sphinxhyphen{}NOW packets, extracts the PWM control data, and applies it directly to the DC motors. This communication flow allows the RC car to respond instantly to user input, managing speed and direction without any physical connection between the devices. \sphinxstepscope \chapter{HOW DOES IT WORK?} \label{\detokenize{overview:how-does-it-work}}\label{\detokenize{overview::doc}} \sphinxAtStartPar The BitByteRider RC car is powered by ESP32\sphinxhyphen{}C3 Breadboard \& Power adapter developmemt board. The Schematic and KiCAd PCB board are available on \sphinxhref{https://github.com/alexandrebobkov/ESP32-C3\_Breadboard-Adapter}{GitHub}: \sphinxurl{https://github.com/alexandrebobkov/ESP32-C3\_Breadboard-Adapter} \section{Reserved Pins \& GPIOs} \label{\detokenize{overview:reserved-pins-gpios}} \sphinxAtStartPar The following table summarizes GPIOs and pins reserved for operations purposes. \sphinxAtStartPar The GPIO numbers correspond to those on the ESP32\sphinxhyphen{}C3 WROOM microcontroller. The Pin number corresponds to the pin on the Breadboard and Power adapter development board. \subsection{Reading the Joystick x\sphinxhyphen{} and y\sphinxhyphen{} axis} \label{\detokenize{overview:reading-the-joystick-x-and-y-axis}} \sphinxAtStartPar To determine the position of the Joystick, the BitRider RC car uses ADC to measure voltage on two GPIOs connected to the joystic x\sphinxhyphen{} and y\sphinxhyphen{} axis potentionometers (\sphinxstylestrong{GPIO0} and \sphinxstylestrong{GPIO1}). \subsection{Controlling the Direction and Speed} \label{\detokenize{overview:controlling-the-direction-and-speed}} \sphinxAtStartPar To set any desired speed of BiteRider RC car, the \sphinxstyleemphasis{ESP32\sphinxhyphen{}C3 Breadboard Adapter DevBoard} uses PWM to control the rotation speed of DR motors. Similarly, to set the direction of the RC car, the rotation speed of corresponding DC motors is changed as required. \sphinxAtStartPar Due to the design and limited number of available GPIOs, the \sphinxstyleemphasis{ESP32\sphinxhyphen{}C3 Breadboard DevBoard} can control rotation speed and direction of DC motors in pairs only (i.e. left and right side). Consequently, this means that the four PWM channels used for controlling the direction of the RC car. \sphinxAtStartPar Based on this constraint, the RC car can only move front, back, and turn/rotate left and right. Any other movements are not possible (i.e. diagonal or sideways). \begin{savenotes}\sphinxattablestart \sphinxthistablewithglobalstyle \centering \begin{tabulary}{\linewidth}[t]{TT} \sphinxtoprule \sphinxtableatstartofbodyhook \sphinxAtStartPar PWM of DC Motors & \sphinxAtStartPar Direction \\ \sphinxhline \sphinxAtStartPar PWM(left) = PWM(right) & \sphinxAtStartPar Straight \\ \sphinxhline \sphinxAtStartPar PWM(left) \textgreater{} PWM(right) & \sphinxAtStartPar Left \\ \sphinxhline \sphinxAtStartPar PWM(left) \textless{} PWM(right) & \sphinxAtStartPar Right \\ \sphinxbottomrule \end{tabulary} \sphinxtableafterendhook\par \sphinxattableend\end{savenotes} \begin{sphinxadmonition}{note}{What is PWM?} \sphinxAtStartPar \sphinxstylestrong{PWM} stands for Pulse Width Modulation. It is a technique used to simulate analog voltage levels using discrete digital signals. It works by rapidly switching a digital GPIO pin between HIGH (on) and LOW (off) states at a fixed frequency (often, at base frequency of 5 kHz). The duty cycle—the percentage of time the signal is HIGH in one cycle determines the effective voltage delivered to a device. A higher duty cycle increases the motor speed, and a lower duty cycle decreases the motor speed. This allows for fine\sphinxhyphen{}grained speed control without needing analog voltage regulators. \end{sphinxadmonition} \sphinxAtStartPar A pair of PWM channels are used per DC motor for defining their rotation speed and direction on each side. In particular, \sphinxstylestrong{GPIO6} and \sphinxstylestrong{GPIO5} provide PWM to the left\sphinxhyphen{} and right\sphinxhyphen{} side DC motors to rotate in a \sphinxstylestrong{clockwise} direction. Similarly, \sphinxstylestrong{GPIO4} and \sphinxstylestrong{GPIO7} provide PWM to the left\sphinxhyphen{} and right\sphinxhyphen{} side DC motors to rotate in a \sphinxstylestrong{counter\sphinxhyphen{}clockwise} direction. Changing PWM on each channel determines the speed and direction of the RC car. \sphinxAtStartPar The table below summarizes the GPIO pins used for PWM to control the direction of the DC motors in the remote\sphinxhyphen{}controlled car. \begin{quote}\begin{description} \sphinxlineitem{class} \sphinxAtStartPar break \end{description}\end{quote} \begin{savenotes}\sphinxattablestart \sphinxthistablewithglobalstyle \centering \begin{tabulary}{\linewidth}[t]{TTTT} \sphinxtoprule \sphinxstyletheadfamily \sphinxAtStartPar GPIOs &\sphinxstyletheadfamily \sphinxAtStartPar State &\sphinxstyletheadfamily \sphinxAtStartPar Description &\sphinxstyletheadfamily \sphinxAtStartPar Function \\ \sphinxmidrule \sphinxtableatstartofbodyhook \sphinxAtStartPar GPIO6, GPIO4 & \sphinxAtStartPar PWM & \sphinxAtStartPar Left \& Right DC Motors spin clockwise & \sphinxAtStartPar Forward \\ \sphinxhline \sphinxAtStartPar GPIO5, GPIO7 & \sphinxAtStartPar PWM & \sphinxAtStartPar Left \& Right DC Motors spin counterclockwise & \sphinxAtStartPar Reverse \\ \sphinxhline \sphinxAtStartPar GPIO6, GPIO7 & \sphinxAtStartPar PWM & \sphinxAtStartPar Left DC Motors spin clockwise. Right DC Motors spin counterclockwise & \sphinxAtStartPar Left \\ \sphinxhline \sphinxAtStartPar GPIO4, GPIO5 & \sphinxAtStartPar PWM & \sphinxAtStartPar Left DC Motors spin counterclockwise. Right DC Motors spin clockwise & \sphinxAtStartPar Right \\ \sphinxbottomrule \end{tabulary} \sphinxtableafterendhook\par \sphinxattableend\end{savenotes} \sphinxAtStartPar The following images illustrate various PWM duty cycles registered by oscilloscope (duty cycles 0\%, 48\% and 91\%, resp.). \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics{{ESP-IDF_Robot_PWM_Duty-0}.bmp} \caption{DC Motor PWM duty cycle 0\%}\label{\detokenize{overview:id1}}\end{figure} \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics{{ESP-IDF_Robot_PWM_Duty-50}.bmp} \caption{DC Motor PWM duty cycle 47.6\%}\label{\detokenize{overview:id2}}\end{figure} \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics{{ESP-IDF_Robot_PWM_Duty-95}.bmp} \caption{DC Motor PWM duty cycle 90.8\%}\label{\detokenize{overview:id3}}\end{figure} \begin{savenotes}\sphinxattablestart \sphinxthistablewithglobalstyle \centering \begin{tabulary}{\linewidth}[t]{TTTT} \sphinxtoprule \sphinxstyletheadfamily \sphinxAtStartPar GPIO &\sphinxstyletheadfamily \sphinxAtStartPar Pin &\sphinxstyletheadfamily \sphinxAtStartPar Function &\sphinxstyletheadfamily \sphinxAtStartPar Notes \\ \sphinxmidrule \sphinxtableatstartofbodyhook \sphinxAtStartPar 0 & \sphinxAtStartPar 16 & \sphinxAtStartPar Joystick x\sphinxhyphen{}axis & \sphinxAtStartPar ADC1\_CH0 \\ \sphinxhline \sphinxAtStartPar 1 & \sphinxAtStartPar 15 & \sphinxAtStartPar Joystick y\sphinxhyphen{}axis & \sphinxAtStartPar ADC1\_CH1 \\ \sphinxhline \sphinxAtStartPar 8 & \sphinxAtStartPar 5 & \sphinxAtStartPar Joystick push button &\\ \sphinxhline \sphinxAtStartPar 6 & \sphinxAtStartPar 4 & \sphinxAtStartPar PWM for clockwise rotation of left\sphinxhyphen{}side motors & \sphinxAtStartPar LEDC\_CHANNEL\_1 \\ \sphinxhline \sphinxAtStartPar 5 & \sphinxAtStartPar 3 & \sphinxAtStartPar PWM for clockwise rotation of right\sphinxhyphen{}side motors & \sphinxAtStartPar LEDC\_CHANNEL\_0 \\ \sphinxhline \sphinxAtStartPar 4 & \sphinxAtStartPar 2 & \sphinxAtStartPar PWM for counter\sphinxhyphen{}clockwise rotation of right\sphinxhyphen{}side motors & \sphinxAtStartPar LEDC\_CHANNEL\_2 \\ \sphinxhline \sphinxAtStartPar 7 & \sphinxAtStartPar 6 & \sphinxAtStartPar PWM for counter\sphinxhyphen{}clockwise rotation of left\sphinxhyphen{}side motors & \sphinxAtStartPar LEDC\_CHANNEL\_3 \\ \sphinxbottomrule \end{tabulary} \sphinxtableafterendhook\par \sphinxattableend\end{savenotes} \section{Fusion of Software with Hardware} \label{\detokenize{overview:fusion-of-software-with-hardware}} \sphinxAtStartPar The \sphinxstyleemphasis{struct} for storing motors PWM values. \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k}{struct}\PYG{+w}{ }\PYG{n+nc}{motors\PYGZus{}rpm}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{p}{;} \end{sphinxVerbatim} \sphinxAtStartPar The function for updating motors’ PWM values. \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{c+c1}{// Function to send data to the receiver} \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{sendData}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{void}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{sensors\PYGZus{}data\PYGZus{}t}\PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Declare data struct} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{crc}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{x\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{y\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{nav\PYGZus{}bttn}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;} \PYG{+w}{ }\PYG{c+c1}{// Display brief summary of data being sent.} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Joystick (x,y) position ( 0x\PYGZpc{}04X, 0x\PYGZpc{}04X )}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{x\PYGZus{}axis}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{y\PYGZus{}axis}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{pwm 1, pwm 2 [ 0x\PYGZpc{}04X, 0x\PYGZpc{}04X ]}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{pwm}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{pwm}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{pwm 3, pwm 4 [ 0x\PYGZpc{}04X, 0x\PYGZpc{}04X ]}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{pwm}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{p}{)}\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{pwm}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{c+c1}{// Call ESP\PYGZhy{}NOW function to send data (MAC address of receiver, pointer to the memory holding data \PYGZam{} data length)} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{result}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{esp\PYGZus{}now\PYGZus{}send}\PYG{p}{(}\PYG{n}{receiver\PYGZus{}mac}\PYG{p}{,}\PYG{+w}{ }\PYG{o}{\PYGZam{}}\PYG{n}{buffer}\PYG{p}{,}\PYG{+w}{ }\PYG{k}{sizeof}\PYG{p}{(}\PYG{n}{buffer}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{c+c1}{// If status is NOT OK, display error message and error code (in hexadecimal).} \PYG{+w}{ }\PYG{k}{if}\PYG{+w}{ }\PYG{p}{(}\PYG{n}{result}\PYG{+w}{ }\PYG{o}{!}\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGE}\PYG{p}{(}\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{ESP\PYGZhy{}NOW}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Error sending data! Error code: 0x\PYGZpc{}04X}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{result}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{deletePeer}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{\PYGZcb{}} \PYG{+w}{ }\PYG{k}{else} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGW}\PYG{p}{(}\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{ESP\PYGZhy{}NOW}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Data was sent.}\PYG{l+s}{\PYGZdq{}}\PYG{p}{)}\PYG{p}{;} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \sphinxAtStartPar The onDataReceived() and onDataSent() are two call\sphinxhyphen{}bacl functions that get evoked on each corresponding event. \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{c+c1}{// Call\PYGZhy{}back for the event when data is being received} \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{onDataReceived}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{mac\PYGZus{}addr}\PYG{p}{,}\PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{data}\PYG{p}{,}\PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{data\PYGZus{}len}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{buf}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{p}{(}\PYG{n}{sensors\PYGZus{}data\PYGZus{}t}\PYG{o}{*}\PYG{p}{)}\PYG{n}{data}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Allocate memory for buffer to store data being received} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGW}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Data was received}\PYG{l+s}{\PYGZdq{}}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{x\PYGZhy{}axis: 0x\PYGZpc{}04x}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{buf}\PYG{o}{\PYGZhy{}}\PYG{o}{\PYGZgt{}}\PYG{n}{x\PYGZus{}axis}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{x\PYGZhy{}axis: 0x\PYGZpc{}04x}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{buf}\PYG{o}{\PYGZhy{}}\PYG{o}{\PYGZgt{}}\PYG{n}{y\PYGZus{}axis}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{PWM 1: 0x\PYGZpc{}04x}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{buf}\PYG{o}{\PYGZhy{}}\PYG{o}{\PYGZgt{}}\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{)}\PYG{p}{;} \PYG{p}{\PYGZcb{}} \PYG{c+c1}{// Call\PYGZhy{}back for the event when data is being sent} \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{onDataSent}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{mac\PYGZus{}addr}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{esp\PYGZus{}now\PYGZus{}send\PYGZus{}status\PYGZus{}t}\PYG{+w}{ }\PYG{n}{status}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGW}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Packet send status: 0x\PYGZpc{}04X}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{status}\PYG{p}{)}\PYG{p}{;} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \sphinxAtStartPar The rc\_send\_data\_task() function runs every 0.1 second to transmit the data to the receiver. \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{c+c1}{// Continous, periodic task that sends data.} \PYG{k}{static}\PYG{+w}{ }\PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{rc\PYGZus{}send\PYGZus{}data\PYGZus{}task}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{void}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{arg}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k}{while}\PYG{+w}{ }\PYG{p}{(}\PYG{n+nb}{true}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k}{if}\PYG{+w}{ }\PYG{p}{(}\PYG{n}{esp\PYGZus{}now\PYGZus{}is\PYGZus{}peer\PYGZus{}exist}\PYG{p}{(}\PYG{n}{receiver\PYGZus{}mac}\PYG{p}{)}\PYG{p}{)} \PYG{+w}{ }\PYG{n}{sendData}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{vTaskDelay}\PYG{+w}{ }\PYG{p}{(}\PYG{l+m+mi}{100}\PYG{+w}{ }\PYG{o}{/}\PYG{+w}{ }\PYG{n}{portTICK\PYGZus{}PERIOD\PYGZus{}MS}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{\PYGZcb{}} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \section{Schematic} \label{\detokenize{overview:schematic}} \noindent\sphinxincludegraphics{{ESP-IDF_Robot_schematic}.png} \sphinxstepscope \chapter{DATA STRUCTS} \label{\detokenize{data:data-structs}}\label{\detokenize{data::doc}} \sphinxAtStartPar The struct serves as the data payload for sending control signals from the transmitting device to the receiver using ESP\sphinxhyphen{}NOW. In addition, it may contain additional data such as telemetry, battery status, etc. The \sphinxstyleemphasis{sensors\_data\_t} struct encapsulates all control commands and sensor states relevant to the vehicle’s operation. It’s intended to be sent from a transmitting device (like a remote control) to a receiver (such as a microcontroller on board of the vehicle). \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k}{typedef}\PYG{+w}{ }\PYG{k}{struct}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{x\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick x\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{y\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick y\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{nav\PYGZus{}bttn}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick push button} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{led}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// LED ON/OFF state} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// PWMs for 4 DC motors} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{+w}{ }\PYG{n}{\PYGZus{}\PYGZus{}attribute\PYGZus{}\PYGZus{}}\PYG{p}{(}\PYG{p}{(}\PYG{n}{packed}\PYG{p}{)}\PYG{p}{)}\PYG{+w}{ }\PYG{n}{sensors\PYGZus{}data\PYGZus{}t}\PYG{p}{;} \end{sphinxVerbatim} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k}{struct}\PYG{+w}{ }\PYG{n+nc}{motors\PYGZus{}rpm}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{p}{;} \end{sphinxVerbatim} \sphinxAtStartPar When used with communication protocols like ESP\sphinxhyphen{}NOW, this struct is \sphinxstylestrong{encoded} into a byte stream, then \sphinxstylestrong{transmitted} at regular intervals or in response to user input, and finally \sphinxstylestrong{decoded} on the receiving end to control hardware. \begin{sphinxadmonition}{note}{What is struct?} \sphinxAtStartPar In C programming, a struct (short for structure) is a user\sphinxhyphen{}defined data type that lets you group multiple variables of different types together under a single name. It’s like a container that holds related information — perfect for organizing data that logically belongs together. Structs are especially powerful in systems programming, embedded projects, and when dealing with raw binary data — like parsing sensor input or transmitting control packets over ESP\sphinxhyphen{}NOW. \end{sphinxadmonition} \section{Data Payload} \label{\detokenize{data:data-payload}} \sphinxAtStartPar \sphinxstyleemphasis{x\_axis} and \sphinxstyleemphasis{y\_axis} fields capture analog input from a joystick, determining direction and speed. \sphinxstyleemphasis{nav\_bttn} represents a joystick push\sphinxhyphen{}button. \sphinxAtStartPar \sphinxstyleemphasis{led} allows the transmitter to toggle an onboard LED and is used for status indication (e.g. pairing, battery warning, etc). \sphinxAtStartPar \sphinxstyleemphasis{motor1\_rpm\_pwm} to \sphinxstyleemphasis{motor4\_rpm\_pwm} provide individual PWM signals to four DC motors. This enables fine\sphinxhyphen{}grained speed control, supports differential drive configurations, and even allows for maneuvering in multi\sphinxhyphen{}directional platforms like omni\sphinxhyphen{}wheel robots. \subsection{Why use \_\_attribute((packed))?} \label{\detokenize{data:why-use-attribute-packed}} \sphinxAtStartPar ESP\sphinxhyphen{}NOW uses fixed\sphinxhyphen{}size data packets (up to 250 bytes). The \sphinxstyleemphasis{\_\_attribute\_\_((packed))} removes compiler\sphinxhyphen{}added padding for precise byte alignment. \sphinxAtStartPar As \sphinxstyleemphasis{packed} attribute tells the compiler not to add any padding between fields in memory, this makes the struct: \begin{itemize} \item {} \sphinxAtStartPar Compact \item {} \sphinxAtStartPar Predictable for serialization over protocols like UART or ESP\sphinxhyphen{}NOW \item {} \sphinxAtStartPar Ideal for low\sphinxhyphen{}latency transmission in embedded systems \end{itemize} \sphinxAtStartPar This ensures the receiver interprets the exact byte layout you expect, minimizing bandwidth and maximizing compatibility across platforms. \sphinxstepscope \chapter{TRANSMITTER} \label{\detokenize{transmitter:transmitter}}\label{\detokenize{transmitter::doc}} \section{Configuration Variables} \label{\detokenize{transmitter:configuration-variables}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{receiver\PYGZus{}mac}\PYG{p}{[}\PYG{n}{ESP\PYGZus{}NOW\PYGZus{}ETH\PYGZus{}ALEN}\PYG{p}{]}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{p}{\PYGZob{}}\PYG{l+m+mh}{0xe4}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0xb0}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x63}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x17}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x9e}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x44}\PYG{p}{\PYGZcb{}}\PYG{p}{;} \PYG{k}{typedef}\PYG{+w}{ }\PYG{k}{struct}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{x\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick x\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{y\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick y\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{nav\PYGZus{}btn}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick push button} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{led}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// LED ON/OFF state} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// PWMs for each DC motor} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{+w}{ }\PYG{n}{\PYGZus{}\PYGZus{}attribute\PYGZus{}\PYGZus{}}\PYG{p}{(}\PYG{p}{(}\PYG{n}{packed}\PYG{p}{)}\PYG{p}{)}\PYG{+w}{ }\PYG{n}{sensors\PYGZus{}data\PYGZus{}t}\PYG{p}{;} \end{sphinxVerbatim} \section{Reading Joystick x\sphinxhyphen{} and y\sphinxhyphen{} Axis Values} \label{\detokenize{transmitter:reading-joystick-x-and-y-axis-values}} \section{Sending \& Ecapsulating Data} \label{\detokenize{transmitter:sending-ecapsulating-data}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{sendData}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{void}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{x\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{x\PYGZus{}axis}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{buffer}\PYG{p}{.}\PYG{n}{y\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{y\PYGZus{}axis}\PYG{p}{;} \PYG{+w}{ }\PYG{c+c1}{// Call ESP\PYGZhy{}NOW function to send data (MAC address of receiver, pointer to the memory holding data \PYGZam{} data length)} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{result}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{esp\PYGZus{}now\PYGZus{}send}\PYG{p}{(}\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{o}{*}\PYG{p}{)}\PYG{n}{receiver\PYGZus{}mac}\PYG{p}{,}\PYG{+w}{ }\PYG{p}{(}\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{p}{)}\PYG{o}{\PYGZam{}}\PYG{n}{buffer}\PYG{p}{,}\PYG{+w}{ }\PYG{k}{sizeof}\PYG{p}{(}\PYG{n}{buffer}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \section{Main Function} \label{\detokenize{transmitter:main-function}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}freertos/FreeRTOS.h\PYGZdq{}} \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}nvs\PYGZus{}flash.h\PYGZdq{}} \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}esp\PYGZus{}err.h\PYGZdq{}} \PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n}{app\PYGZus{}main}\PYG{p}{(}\PYG{k+kt}{void}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{c+c1}{// Initialize internal temperature sensor} \PYG{+w}{ }\PYG{n}{chip\PYGZus{}sensor\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{c+c1}{// Initialize NVS} \PYG{+w}{ }\PYG{n}{esp\PYGZus{}err\PYGZus{}t}\PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{k}{if}\PYG{+w}{ }\PYG{p}{(}\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{o}{=}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERR\PYGZus{}NVS\PYGZus{}NO\PYGZus{}FREE\PYGZus{}PAGES}\PYG{+w}{ }\PYG{o}{|}\PYG{o}{|}\PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{o}{=}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERR\PYGZus{}NVS\PYGZus{}NEW\PYGZus{}VERSION\PYGZus{}FOUND}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}erase}\PYG{p}{(}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{\PYGZcb{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{wifi\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{joystick\PYGZus{}adc\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{transmission\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{system\PYGZus{}led\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \sphinxstepscope \chapter{RECEIVER} \label{\detokenize{receiver:receiver}}\label{\detokenize{receiver::doc}} \section{Configuration Variables} \label{\detokenize{receiver:configuration-variables}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{transmitter\PYGZus{}mac}\PYG{p}{[}\PYG{n}{ESP\PYGZus{}NOW\PYGZus{}ETH\PYGZus{}ALEN}\PYG{p}{]}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{p}{\PYGZob{}}\PYG{l+m+mh}{0x9C}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x9E}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x6E}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x14}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0xB5}\PYG{p}{,}\PYG{+w}{ }\PYG{l+m+mh}{0x54}\PYG{p}{\PYGZcb{}}\PYG{p}{;} \PYG{k}{typedef}\PYG{+w}{ }\PYG{k}{struct}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{x\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick x\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{y\PYGZus{}axis}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick y\PYGZhy{}position} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{nav\PYGZus{}bttn}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Joystick push button} \PYG{+w}{ }\PYG{k+kt}{bool}\PYG{+w}{ }\PYG{n}{led}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// LED ON/OFF state} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// PWMs for 4 DC motors} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{+w}{ }\PYG{n}{\PYGZus{}\PYGZus{}attribute\PYGZus{}\PYGZus{}}\PYG{p}{(}\PYG{p}{(}\PYG{n}{packed}\PYG{p}{)}\PYG{p}{)}\PYG{+w}{ }\PYG{n}{sensors\PYGZus{}data\PYGZus{}t}\PYG{p}{;} \end{sphinxVerbatim} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k}{struct}\PYG{+w}{ }\PYG{n+nc}{motors\PYGZus{}rpm}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor1\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor2\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor3\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{+w}{ }\PYG{k+kt}{int}\PYG{+w}{ }\PYG{n}{motor4\PYGZus{}rpm\PYGZus{}pwm}\PYG{p}{;} \PYG{p}{\PYGZcb{}}\PYG{p}{;} \end{sphinxVerbatim} \section{Receiving \& Extracting Data} \label{\detokenize{receiver:receiving-extracting-data}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n+nf}{onDataReceived}\PYG{+w}{ }\PYG{p}{(}\PYG{k}{const}\PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{mac\PYGZus{}addr}\PYG{p}{,}\PYG{+w}{ }\PYG{k}{const}\PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{o}{*}\PYG{n}{data}\PYG{p}{,}\PYG{+w}{ }\PYG{k+kt}{uint8\PYGZus{}t}\PYG{+w}{ }\PYG{n}{data\PYGZus{}len}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}LOGI}\PYG{p}{(}\PYG{n}{TAG}\PYG{p}{,}\PYG{+w}{ }\PYG{l+s}{\PYGZdq{}}\PYG{l+s}{Data received from: \PYGZpc{}02x:\PYGZpc{}02x:\PYGZpc{}02x:\PYGZpc{}02x:\PYGZpc{}02x:\PYGZpc{}02x, len=\PYGZpc{}d}\PYG{l+s}{\PYGZdq{}}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{0}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{1}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{2}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{3}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{4}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{mac\PYGZus{}addr}\PYG{p}{[}\PYG{l+m+mi}{5}\PYG{p}{]}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{data\PYGZus{}len}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{memcpy}\PYG{p}{(}\PYG{o}{\PYGZam{}}\PYG{n}{buf}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{data}\PYG{p}{,}\PYG{+w}{ }\PYG{k}{sizeof}\PYG{p}{(}\PYG{n}{buf}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{x\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{buf}\PYG{p}{.}\PYG{n}{x\PYGZus{}axis}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{y\PYGZus{}axis}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{buf}\PYG{p}{.}\PYG{n}{y\PYGZus{}axis}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \section{Main Function} \label{\detokenize{receiver:main-function}} \begin{sphinxVerbatim}[commandchars=\\\{\}] \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZlt{}string.h\PYGZgt{}} \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}freertos/FreeRTOS.h\PYGZdq{}} \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}nvs\PYGZus{}flash.h\PYGZdq{}} \PYG{c+cp}{\PYGZsh{}}\PYG{c+cp}{include}\PYG{+w}{ }\PYG{c+cpf}{\PYGZdq{}esp\PYGZus{}err.h\PYGZdq{}} \PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{k+kt}{void}\PYG{+w}{ }\PYG{n}{app\PYGZus{}main}\PYG{p}{(}\PYG{k+kt}{void}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{c+c1}{// Initialize NVS} \PYG{+w}{ }\PYG{n}{esp\PYGZus{}err\PYGZus{}t}\PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{k}{if}\PYG{+w}{ }\PYG{p}{(}\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{o}{=}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERR\PYGZus{}NVS\PYGZus{}NO\PYGZus{}FREE\PYGZus{}PAGES}\PYG{+w}{ }\PYG{o}{|}\PYG{o}{|} \PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{o}{=}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERR\PYGZus{}NVS\PYGZus{}NEW\PYGZus{}VERSION\PYGZus{}FOUND}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{\PYGZob{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}erase}\PYG{p}{(}\PYG{p}{)}\PYG{+w}{ }\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{nvs\PYGZus{}flash\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{\PYGZcb{}} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{+w}{ }\PYG{n}{ret}\PYG{+w}{ }\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{wifi\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{n}{esp\PYGZus{}now\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{esp\PYGZus{}now\PYGZus{}peer\PYGZus{}info\PYGZus{}t}\PYG{+w}{ }\PYG{n}{transmitterInfo}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{p}{\PYGZob{}}\PYG{l+m+mi}{0}\PYG{p}{\PYGZcb{}}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{memcpy}\PYG{p}{(}\PYG{n}{transmitterInfo}\PYG{p}{.}\PYG{n}{peer\PYGZus{}addr}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{transmitter\PYGZus{}mac}\PYG{p}{,}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}NOW\PYGZus{}ETH\PYGZus{}ALEN}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{transmitterInfo}\PYG{p}{.}\PYG{n}{channel}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{l+m+mi}{0}\PYG{p}{;}\PYG{+w}{ }\PYG{c+c1}{// Current WiFi channel} \PYG{+w}{ }\PYG{n}{transmitterInfo}\PYG{p}{.}\PYG{n}{ifidx}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n}{ESP\PYGZus{}IF\PYGZus{}WIFI\PYGZus{}STA}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{transmitterInfo}\PYG{p}{.}\PYG{n}{encrypt}\PYG{+w}{ }\PYG{o}{=}\PYG{+w}{ }\PYG{n+nb}{false}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{n}{esp\PYGZus{}now\PYGZus{}add\PYGZus{}peer}\PYG{p}{(}\PYG{o}{\PYGZam{}}\PYG{n}{transmitterInfo}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{ESP\PYGZus{}ERROR\PYGZus{}CHECK}\PYG{p}{(}\PYG{n}{esp\PYGZus{}now\PYGZus{}register\PYGZus{}recv\PYGZus{}cb}\PYG{p}{(}\PYG{p}{(}\PYG{k+kt}{void}\PYG{o}{*}\PYG{p}{)}\PYG{n}{onDataReceived}\PYG{p}{)}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{n}{system\PYGZus{}led\PYGZus{}init}\PYG{p}{(}\PYG{p}{)}\PYG{p}{;} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.}\PYG{+w}{ }\PYG{p}{.}\PYG{p}{.}\PYG{p}{.} \PYG{p}{\PYGZcb{}} \end{sphinxVerbatim} \sphinxstepscope \chapter{WORK\sphinxhyphen{}IN\sphinxhyphen{}PROGRESS WALK THROUGH} \label{\detokenize{progress:work-in-progress-walk-through}}\label{\detokenize{progress::doc}} \section{Finished Work} \label{\detokenize{progress:finished-work}} \noindent\sphinxincludegraphics{{ESP-IDF_Robot}.jpg} \section{Chassis} \label{\detokenize{progress:chassis}} \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics[height=300\sphinxpxdimen]{{chassi-progress_002d}.jpg} \caption{Completed chassis with only DC motor controllers installed.}\label{\detokenize{progress:id1}}\end{figure} \section{Wiring} \label{\detokenize{progress:wiring}} \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics[height=750\sphinxpxdimen]{{chassi-progress_003a}.jpg} \caption{Completed wiring.}\label{\detokenize{progress:id2}}\end{figure} \section{Motor Wires Harness} \label{\detokenize{progress:motor-wires-harness}} \begin{figure}[htbp] \centering \capstart \noindent\sphinxincludegraphics{{motors-wiring-harness-001}.jpg} \caption{DC Motors wires secured inside harnes.}\label{\detokenize{progress:id3}}\end{figure} \sphinxstepscope \chapter{REFERENCES} \label{\detokenize{references:references}}\label{\detokenize{references::doc}} \section{GitHub} \label{\detokenize{references:github}} \sphinxAtStartPar Complete source \sphinxhref{https://github.com/alexandrebobkov/ESP-Nodes/blob/main/ESP-IDF\_Robot/README.md}{code} with README.md file: \sphinxurl{https://github.com/alexandrebobkov/ESP-Nodes/blob/main/ESP-IDF\_Robot/README.md} \sphinxAtStartPar KiCAd \sphinxhref{https://github.com/alexandrebobkov/ESP32-C3\_Breadboard-Adapter}{Schematic} and PCB design: \sphinxurl{https://github.com/alexandrebobkov/ESP32-C3\_Breadboard-Adapter} \renewcommand{\indexname}{Index} \printindex \end{document}