Freenove ESP32 User Manual

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Chapter 6 Battery
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BatteryPower.cpp
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#include "BatteryPower.h"
void setupAdc(){
analogReadResolution(12);
analogSetAttenuation(ADC_11db);
adcAttachPin(PIN_ANALOG_IN);
}
uint32_t getBatteryVoltage(){
uint32_t adc_reading = 0;
for (int i = 0; i < NUM_OF_SAMPLES; i++){
adc_reading += analogRead(PIN_ANALOG_IN);
}
adc_reading /= NUM_OF_SAMPLES;
uint32_t voltage = adc_reading*3300/4096;
return voltage * VOLATAGE_RATIO;
}
ADC data sampling accuracy setting. Here it is set to 12 bits. 2^12=4096, so the sampling data range of ADC
is 0-4095.
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analogReadResolution(12);
ADC sampling voltage range setting of ESP32, which is 0-3.3V. ADC_11db represents the maximum range.
Combined with the above analogReadResolution() function, when the voltage of the ADC collection point is
0V, the value collected by the ADC is 0; when the voltage of the ADC collection point is 3.3V, the value
collected by the ADC is 4095.
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analogSetAttenuation(ADC_11db);
Associate the ADC configuration to the pin.
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adcAttachPin(PIN_ANALOG_IN);
Use analogRead(PIN_ANALOG_IN) to capture the ADC value at the ESP32 pin.
Continuously collect NUM_OF_SAMPLES ADC values at the ESP32 pins and calculate the average.
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uint32_t adc_reading = 0;
for (int i = 0; i < NUM_OF_SAMPLES; i++){
adc_reading += analogRead(PIN_ANALOG_IN);
}
adc_reading /= NUM_OF_SAMPLES;
Convert the ADC value to the actual measured voltage value. The unit is millivolts.
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uint32_t voltage = adc_reading*3300/4096;
We know from the previous introduction that the voltage at the ESP32 pin is 1/4 of the battery voltage.
Therefore, the voltage value of the battery can be obtained by multiplying the voltage value measured by the
ADC by VOLATAGE_RATIO(4).
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return voltage * VOLATAGE_RATIO;

Freenove ESP32 Specifications

General

Clock Speed	240 MHz
RAM	520 KB SRAM
Wi-Fi	802.11 b/g/n
UART	3
Operating Voltage	3.3V
Input Voltage	5V
DC Current per I/O Pin	40mA
USB	Micro USB
Microcontroller	ESP32
Chip	ESP32
Bluetooth	Bluetooth v4.2 BR/EDR and BLE standard
ADC Channels/Analog Input Pins	18
I2C	Yes
SPI	Yes
Interfaces	I2C, SPI, UART
CPU	Dual-Core 32-bit LX6 Microprocessor

Summary

Safety and Precautions

General Safety Guidelines

Outlines crucial safety measures for handling and using the robot kit to prevent injury or damage.

Hardware Components

ESP32 Expansion Board and Modules

Details the ESP32 expansion board, ESP32 module, camera, and other electronic components.

Mechanical Parts and Tools

Lists acrylic parts, servos, screws, nuts, standoffs, and necessary tools for assembly.

Software and Firmware Setup

CH340 Driver and Firmware Installation

Guides on installing the CH340 driver and burning firmware for OS.

Freenove App and Arduino IDE Setup

Covers installing the Freenove app and setting up the Arduino IDE environment.

ESP32 Pin Configuration

Details ESP32 pins, their functions, and descriptions for robot connectivity.

Robot Assembly and Calibration

Step-by-Step Assembly Guide

Details the process of assembling the robot's body, legs, head, and wiring.

Servo Wiring and Calibration

Guides on connecting ESP32, batteries, servos, and performing robot calibration.

Robot Functionality and Control

Freenove App Features

Overviews app features like Wi-Fi config, LED control, and interaction.

Ultrasonic Ranging and Motion Control

Explains ultrasonic sensor and provides code for robot movements.

Communication Protocols and Commands

Explains communication commands via Serial, BLE, Wi-Fi, and development aspects.