Arduino UNO R3 (ATmega328P)
by Arduino / CH340 clone
SKU: PSA-CMP-UNO-R3
No reviews yetTypical India street price
₹350–₹900
The classroom workhorse board for digital/analog I/O, sketches, and PSA Lab USB projects.
Interface: GPIO, UART, I2C, SPI, analog
UNO remains the USB serial classroom board for many PSA starter activities.
Open PSA LabGet notified if we start selling this part
Concept
A microcontroller is a tiny computer on one chip: CPU, flash memory, RAM, timers, and I/O pins. The Arduino UNO R3 mounts that chip on a breadboard-friendly PCB with USB programming, a 5 V regulator, and labelled headers so students can wire sensors without soldering.
A little theory
The ATmega328P runs at 16 MHz from a ceramic resonator. Digital pins are CMOS I/O: HIGH is about 5 V, LOW about 0 V, with roughly 20–40 mA absolute maximum per pin (stay under ~20 mA in class). The 10-bit ADC turns 0–5 V on A0–A5 into integers 0–1023 (about 4.9 mV per count). PWM on pins 3,5,6,9,10,11 fakes “analog” voltage by switching HIGH/LOW rapidly while duty cycle sets average power. Timers also drive millis() and Servo pulses. Always share GND with every module; motors need a separate driver and supply because USB and the on-board regulator cannot feed stall current.
How it works in a project
USB-serial (ATmega16U2 or CH340) loads a .hex sketch into flash. setup() runs once; loop() repeats forever. Use digitalWrite/digitalRead for switches and LEDs, analogRead for pots/sensors, and libraries (Servo, Wire, SPI) for modules. In the IDE pick “Arduino UNO”.
Classroom & project use
- Traffic-light and lamp kits
- Ultrasonic distance meter
- Line-follower brain
- PSA Lab USB classroom experiments
Buying in India
Precautions
- Never feed more than 5 V into I/O pins
- Share GND with all modules
- Motors need a driver + separate supply — not USB 5 V
Specifications
| MCU | ATmega328P |
| Clock | 16 MHz |
| Flash | 32 KB |
| SRAM | 2 KB |
| I/O | 14 digital + 6 analog |
| Logic | 5V |
| Category | Microcontrollers |
| Difficulty | Beginner |
| Voltage | 5V (USB / 7–12V jack) |
| Interface | GPIO, UART, I2C, SPI, analog |
Pinout
D0/D1 = UART RX/TX (avoid if using USB serial) D2–D13 digital (D3,5,6,9,10,11 PWM) A0–A5 analog / D14–D19 5V, 3.3V, GND, VIN SCL/SDA also on D19/D18
