On this mission, I will current you methods a Bipolar LED Driver Circuit can be utilized using 8051 Microcontroller. A Bipolar LED is completely completely different from an on a regular basis Bi-color LED throughout the sense {{that a}} Bipolar LED has solely two leads whereas an on a regular basis Bi-color LED has three leads. 


A Bi coloration LED is a specific sort of LED which consists of two diodes associated in inverse course to 1 one other inside a bundle. A bi coloration LED usually consists of three terminals – a typical pin and two separate pins. The widespread pin can be associated to ground if it is a widespread cathode LED or associated to +5V present, if it is a widespread anode. Nonetheless, there could also be one different sort of bi coloration LED with two terminals often known as the Bipolar LED.

The machine options as per the constructive signal given to one in all many terminals. For instance for a inexperienced and purple bi coloration LED, a constructive signal on the inexperienced terminal and damaging signal at purple terminal ensures the inexperienced LED to be forward biased and purple LED to be reverse biased. This causes the inexperienced gentle to flash. Equivalent is the case for the purple LED.

Nonetheless, if every the terminals are given damaging alerts, neither of the diodes would conduct and the machine would keep off.  If constructive signal is utilized to every the terminals, a singular coloration, based totally on the combination of the LED colors, would flash.

The following is the image of a purple – inexperienced Bipolar LED. It seems to be like like an on a regular basis LED.

Related Publish: Bi Color LED Dancing Lights

On this mission, we’re designing a straightforward bi coloration LED driver circuit using an 8051 Microcontroller. The LED used proper right here has a forward voltage drop of two.2V and subsequently can be biased using a 5V present. The administration is accomplished by the microcontroller program, based totally on the inputs given from two push buttons.

Principle behind Bipolar LED Driver Circuit

The circuit makes use of a microcontroller to drive the bipolar LED. The enter command is given from the two push buttons and based totally on the inputs; the microcontroller is configured to ship relevant HIGH or LOW alerts to the two output pins. These output pins are associated to the terminals of the bi-polar LED.

Bipolar LED Driver Circuit Diagram

Bipolar LED Driver Circuit Diagram

Components Required

  • 8051 Microcontroller (AT89C51 is used proper right here)
  • Programmer for 8051 Microcontroller
  • 11.0592 MHz Crystal
  • Capacitors – 2 X 33pF, 10µF
  • Resistors – 150Ω, 10KΩ X 2
  • Push Buttons X 3
  • Bipolar LED (two leads)
  • Connecting Wires
  • Breadboard
  • Vitality Present

Bipolar LED Driver Circuit Design

It is a straightforward circuit and the design primarily entails designing the interfacing of Microcontroller, designing the oscillator and reset circuits for the microcontroller and assortment of the LED resistor.

The microcontroller interfacing is accomplished by connecting two push button switches to port P0 Pins P0.6 and P0.7 and connecting the two terminals of bipolar LED to port P0 Pins P0.zero and P0.1.

The oscillator design is accomplished by deciding on two 33pF ceramic capacitors in an effort to current stability. The clock signal is generated using an 11MHz Crystal Oscillator. The reset circuit is designed by deciding on an electrolyte capacitor of 10uF and a resistor of 10Okay to understand a reset pulse width of 100ms. The voltage drop all through the resistor is saved spherical 1.2V.

Software program program Part of the Enterprise

The software program program part of design entails writing the code for the microcontroller and producing the .hex file. This entails the subsequent steps.

  1. Create a model new mission throughout the Keil µVision IDE window.
  2. Select the objective machine for the mission. Proper right here, we’re using AT89C51 from Atmel (now Microchip).
  3. Create a model new file such {{that a}} clear textual content material self-discipline appears.
  4. Write the code using the subsequent algorithm.
  5. Assign variables to the enter and output port.
  6. Study if one in all many inputs is full of life low.
  7. In case one in all many inputs is at logic low, assign a logic extreme signal to one in all many LED terminals.
  8. In case none are at logic low, make sure the LED is switched off.
  9. Save the code with .c extension.
  10. Add the code to the provision folder beneath objective folder.
  11. Create a Hex file by clicking the ‘Configure Flash Devices’ beneath ‘Flash’ menu.

Moreover Be taught the Related Publish: 230v LED Driver Circuit


Working of Bipolar LED Driver Circuit

As quickly because the circuit is switched on, the microcontroller repeatedly scans the enter pins at port P0. Suppose the first button (P0.6) is pressed, the microcontroller receives a low logic signal on the corresponding enter pin and accordingly it assigns a extreme logic signal to pin P0.zero and low logic signal to pin P0.1. This causes the purple gentle of the LED to glow.

Bipolar LED Driver Circuit GIF Image

Now when the second button is pressed, the microcontroller will accordingly assign a low logic signal to the pin P0.zero and a extreme logic signal to pin P0.1. This causes the inexperienced gentle to glow.

The LED stays on until the button is launched.

Bipolar LED Driver Functions

  1. This circuit could be utilized for indication features.
  2. This circuit could be utilized at features the place flashing of sunshine is required, as in beacon flashing.

Limitations of Bipolar LED Driver Circuit

  1. The first limitation of the mission won’t be in terms of the efficiency nevertheless reasonably the availability of the Bipolar LEDs.



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