Summary of "Embedded Systems and Design & Development - Feb 19, 2026 | Afternoon | VisionAstraa EV Academy"

Context

Hands-on tutorial/demo from VisionAstraa EV Academy using an Arduino Uno (ATmega328) and Tinkercad to develop and integrate motor control and temperature sensing for a basic battery thermal management system (BTMS).

Key technical concepts & components

Microcontroller
- Arduino Uno (ATmega328). Six PWM pins available; the example uses PWM pin 3.
Power switch
- N‑channel MOSFET (NMOS). MOSFET terminals: gate (control), drain and source (power).
- Important: gate drive must be referenced to the MOSFET source and share the microcontroller ground.
PWM motor control
- PWM duty cycle (0–255 value in Arduino analogWrite) controls average voltage across a DC motor and thus speed.
- PWM produces ripple; Tinkercad simulation shows small voltage variation.
Temperature sensing
- Analog temperature sensor connected to ADC input A0. Program converts ADC reading → voltage → temperature using a characterized formula.
Indicators and control outputs
- Built-in LED used as a status indicator (on when temperature is within the specified range).
- PWM output used to drive the coolant circulation motor.
Debugging tools
- Serial monitor (baud 9600) for printing temperature/values.
- Oscilloscope and multimeter for probing signals.
- Software breakpoints to inspect registers.
Simulation vs. high-fidelity modeling
- Tinkercad: recommended for beginner-level code/circuit logic checks.
- For accurate electrical behavior use SPICE tools (LTSpice, QSpice, PSpice).
- MATLAB/Simulink can be used but is less suited for detailed circuit fidelity.

Safety note: Always tie MOSFET source to the microcontroller ground so the gate voltage reference is correct — otherwise the MOSFET will not behave as expected.

Tutorial — step-by-step points demonstrated

Wiring sanity
- Tie grounds between the MCU and power switches; otherwise the MOSFET gate reference is wrong.
Basic PWM test
- Run Arduino code producing PWM on pin 3.
- Observe motor speed and multimeter reading while varying duty cycle (0–255).
Temperature read test
- Load code into Tinkercad, move the temperature slider, verify ADC value, converted voltage, and temperature on the serial monitor.
LED status test
- Turn built‑in LED on when sensed temperature is within a safe range (example: 15–35 °C).
Integration
- Combine temperature sensing and motor control so motor (coolant circulation) speed is adjusted by temperature bands (discrete control via nested if/else).
- Example discrete mapping:
  - < 20 °C: motor off (no coolant circulation)
  - 20–25 °C: motor at ~1/4 speed
  - 25–30 °C: higher speed
  - 35 °C: full speed (maximum coolant circulation)
Safety / additional features (design guidance)
- Battery isolation: open MOSFET switch (disconnect charger/battery) if temperature exceeds a critical threshold (example: 80–90 °C).
- Heater: turn on heater if temp < 5 °C until the temperature reaches a safe minimum (e.g., 15 °C).
- Development approach: prefer modular, top-down requirement decomposition and bottom-up implementation/testing — break system into tasks (read temp, control motor, isolate battery), test separately, then integrate.

Code / resources shared

Arduino sketches shared via qext.in (downloadable). Session used short retrieval codes (examples in subtitles: “VCk”, “BP GT”, and others) for participants to fetch the example sketches.
Advice on program structure:
- Set pinMode for PWM and built‑in LED as outputs; A0 as input.
- Serial.begin(9600) for debug prints.
- Remove duplicate lines noted in circulated code.

Implementation tips & recommendations

Use Tinkercad for quick logic and code testing; do not expect perfect electrical behavior — it is for learning/debugging logic.
For realistic electrical performance, ripple, and analog characteristics, simulate in SPICE (LTSpice, QSpice, PSpice).
Use serial prints and instrumentation (oscilloscope, DMM) to debug; use software breakpoints to inspect registers during execution.
Consider using switch/case constructs instead of many nested if/else for clearer multi-condition logic.
For smoother/continuous coolant control, consider moving from discrete bands to a control algorithm (e.g., a P-controller) rather than only on/off or stepped PWM.

Main speakers / sources referenced

Trainer/instructor from VisionAstraa EV Academy (led demo and code walkthroughs).
Hardware/software referenced: Arduino Uno (ATmega328), NMOS MOSFET, DC motor, analog temperature sensor, Tinkercad (simulation), qext.in (code sharing), and SPICE tools (LTSpice, QSpice, PSpice).