This article is written to describe the design and working of a simple LED cube circuit. Most of the LED cube circuits are designed using a microcontroller. However, to have a circuit without any difficulties of programming, we decided upon a simple idea of driving the cube using just a timer and counter arrangement. Here we arrange a total of 27 LEDs in a cubical arrangement such that there are 9 sets of a trio of LEDs. Apart from the LEDs, all we need is a 555 Timer IC and two 4017 counter ICs. IC 4017 is a CMOS decade counter IC with inbuilt counter come decoder circuit. Reason for using the 4017 IC is its ability to drive the LEDs directly without requiring any BCD decoder.
3X3X3 LED Cube Circuit Principle:
This circuit is based on the principle of driving LEDs using the clock pulses. The idea is to make the cube glow in a gradual transition from one set of the trio to each face of the cube to the whole cube itself. This is achieved by using two counters such that the first counter comes to play for first nine pulses and each of the trios of LEDs glows for each pulse. The second counter comes to play from the 10th pulse and each face of the cube starts glowing. The clock pulses are given using a 555 timer arranged in astable mode.
3X3X3 LED Cube Circuit Diagram:
3X3X3 LED Cube Circuit Design:
First part of design involves designing 555 Timer as an astable multivibrator. Here we assume our required time period to be around 1 second. As the frequency of output signal given by f = 1.44/ (Ra+Rb) C and values of C assumed to be around 100uF, we calculate the values of both the resistors to be around 10K.
The second part of the design involves designing the counter unit. Since here we are using only one counter, the divide by 10 output pin is left unconnected.
In cascading operation, the divide by 10 output pin or the carry out pin is connected to either the clock pin or carry out pin of another counter. The master reset pin and the clock enable pins are both connected to ground.
The third and most important part involves designing the LED cube circuit. We achieve this by arranging 9 set of a series trio of LEDs in a cubical manner such that for each trio, the cathode of each LED is connected to the anode of another and each trio of LEDs is connected in parallel to another such that the cathodes of upper LEDs are connected to each other, resulting in a 3 by 3 by 3 LED cube arrangement. Anodes of all the LEDs are connected together to the ground potential.
Working of 3X3X3 LED Cube Circuit
The circuit operation commences once the switch S1 is bought to the closed position. 555 Timer IC produces the required clock pulses used to trigger the counters.
This is achieved by the astable operation of 555 timer used to produce high and low clock pulses of required interval. Output pulse from the IC is fed to the two counter ICs in parallel arrangement, so as to give the clock signals simultaneously. Here the two counters are arranged in cascading arrangement. The IC 4017 consists of a 5 stages Johnson counter and display decoder circuitry. It produces a high logic signal at its output every time the input clock pulse is a high logic signal. In other words for each positive clock pulse received the counter output at the corresponding output pin will go high. The counter IC will function till the reset pin and clock enable pins are grounded. Since each output pin is connected to each of the series arrangement of LEDs, every time one of the output pins is at logic high, the corresponding series of LEDs would glow.
For example for the first clock pulse when pin 3 of the counter IC goes high, the connected trio of LEDs start glowing. For the first 9 pulses, each trio of LEDs glows.
Thus this circuit displays a spectacular view of the LED cube wherein for each clock pulse, each trio of LEDs glow and since the time period of clock pulses is quite low, and the cube appears to blink.
3X3X3 LED Cube Circuit Applications:
- This circuit can be used as at homes for decoration purpose.
- This circuit can be modified with further changes to make the LED cube glow as a whole.
- It can be used at home lighting system.
3X3X3 LED Cube Circuit Limitations:
- The circuit is complicated and requires complex connections.
- The use of digital counter ICs causes time delay owing to the propagation delay of the digital ICs.
- This is a theoretical circuit and may require changes.
- The use of CMOS devices causes the problem of being static and cannot be handled with bare hands.
- This circuit does not have the provision to switch on all the LEDs simultaneously.