ESP32-based Development Board for Robotics and Embedded Applications
ESP32-based Development Board
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The SRA board is a development board based on ESP32 with on-board peripherals like programmable LEDs, switches, sensor ports for Line Sensor Array and MPU-6050, protection circuit for over-current and reverse voltage and motor drivers.
In general, every development board has the following basic features:
Now that we covered basics of development boards, let us talk about the changes made in the new design.
Feature | SRA Board 2019 | SRA Board 2020 | SRA Board 2022 | SRA Board 2023 |
---|---|---|---|---|
12V to 5V | LM7805 Linear Regulator | LM2596 Buck Converter | LM2576-S Buck Converter | LM2576-S Buck Converter |
5V to 3.3V | LD33 | AMS1117-3.3 | AMS1117-3.3 | AMS1117-3.3 |
Reverse Voltage Protection | Diodes | P-MOSFET | Diodes | Diodes |
Line Sensing Arrays (LSA) | Photodiodes | Photodiodes | Photodiodes | IR Sensors |
Number of LSA Sensors | 4 | 4 | 4 | 5 |
Motor Driver | L298N | TB6612FNG | TB6612FNG | TB6612FNG |
Stepper Motor Driver | - | - | - | A4988 |
No. of DC Motor Channels | 2 | 4 | 4 | 2 |
No. of Stepper Motor Channels | 0 | 0 | 0 | 1 |
No. of Switches | 2 | 4 | 4 | 4 |
No. of LEDs | 2 | 8 | 8 | 8 |
Over Current Protection | Bulky Glass Fuses | Bulky Glass Fuses | PTC Resettable Fuses | PTC Resettable Fuses |
Sensor Port Connectors | FRC (Fused Ribbon Cable) Connectors | JST (Japan Solderless Terminal) Connectors | JST Connectors | JST Connectors |
Component Type and Board Size | THT (Through Hole), Big | THT (Through Hole), Big | SMD(Surface Mount Device), Smaller | SMD(Surface Mount Device), Smaller |
The new edition has 1x TB6612FNG motor drivers which allow a maximum of 2 motors to be controlled. This motor driver is characterized by its operation in two modes - Normal mode and Parallel mode:
The power supply must be provided using one and only one of the above options.Otherwise, the board and/or the power supply source can be damaged.
Currently 300rpm rated BO motors were ultilised for application. These are brushed DC motors functioning currently on 12v working on PWM concept.
These BO motors drain a lot of current during operation. 90 - 100 mA - during normal operation. But they drain about 600 - 700 mA current - during momentary or forced stalling. Momentary stalling happens by itself.
For self balancing operation - the MCU communicates with MPU6050 for the current orientational readings and accordingly gives commands to the motor driver and thus the motors.
When this PWM goes over 50% duty cycle, the error in MPU readings become large and the motor rotate with full speed, thus not self-balancing the setup.
The following inspections were carried out os far so solve this issue.