Project idea
Design a low‑cost, student‑friendly BLDC speed control and RPM measurement system where target speed is entered using push buttons, the microcontroller generates PWM to the power stage, and an IR sensor measures real‑time RPM shown on a 16x2 LCD.
The setup suits labs and small benches that need controllable rotational speed for drilling, spinning, and lathe demos while maintaining electrical isolation between control and power sections.
Project description
The input phase accepts desired RPM via panel push buttons; the processing phase uses an AT89S52 with 11.0592 MHz timebase to generate PWM and compute RPM from IR sensor edges; the output phase drives a 12V BLDC load through an opto‑isolated MOSFET stage.
RPM is displayed on a 16x2 character LCD, and a 12V/2A adapter powers the board and motor, with a universal protoboard/zero‑PCB used for assembly.
Total list of components
8051 Microcontroller (AT89S52)
11.0592 MHz crystal
16x2 alphanumeric LCD
IR speed sensor module (LM393/TCRT type)
Optocoupler (PC817)
N‑channel MOSFET (IRFZ44N)
12V BLDC fan‑type motor (representative BLDC load)
12V 2A DC power adapter
PCB/protoboard (zero PCB)
Breadboard (optional for prototyping)
LEDs
Diodes
Resistors
Capacitors
Transistors (signal)
Push buttons
Switch
IC sockets
Cables and connectors
Features
Setpoint entry via push buttons with live RPM feedback on 16x2 LCD for closed‑loop usability.
IR sensor‑based tachometry for robust RPM counting across 2–30 cm sensing range modules.
PWM drive using AT89S52 timers and an opto‑isolated MOSFET power stage for safer motor control.
12V BLDC load compatibility for lab fans, spindles, and small fixtures using standard 12V supplies.
Modular protoboard assembly for easy debugging and upgrades.
Applications
Educational labs demonstrating BLDC speed control and tachometry fundamentals.
Benchtop drilling/spinning and light lathe demos needing adjustable RPM.
Ventilation and enclosure airflow experiments with 12V BLDC fans.
Project Includes:
Fully assembled and tested circuit
Circuit diagram
Source code
(For DIY KITs - only the components will be provided)
Project Types:
- DIY KIT(Do IT YourSelf KIT) - We are providing only components in this kit for this project
- DIY KIT with Code & Circuit Connections - Along with the components, you will get the Code and the Circuit Connections file to help you build the project easily.
- Readymade Breadboard - We are providing fully assembled, tested and ready-made project using plug-n-play jumper wires and breadboard with all the other components, code & circuit diagram.
- Readymade Soldered - We are providing fully assembled, tested and ready-made project soldered on a PCB with all the other components, code & circuit diagram.
Dimensions in cm
Controller board approx: 10 × 8 × 3 cm (based on 7×9 to 9×15 cm protoboards and LCD outline 8.0 × 3.6 cm).
Front display area: 8.0 × 3.6 cm for 16×2 cm module, allowing compact enclosure windows.
Shipping dimensions in cm
Boxed kit: 20 × 15 × 10 cm with protective padding for LCD, sensor, and power adapter.
Weight
Approximate kit weight: ~0.35 kg considering LCD (~33 g), PCB (~40 g), 12V adapter (~100 g), BLDC fan, and components.
Estimate project weight
Assembled unit on PCB with cabling typically 1 kg depending on enclosure and wiring length.
Notes: All the products are made by LearnElectronics India and not for re-sale.
8051 BLDC RPM Display with Speed Control
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