Circuit Analysis and Production of Two-Dimensional Colored Light Controller

This color light controller can control five colored lights to light up row by row, and then turn off row by row. If a certain number of colored lights are combined and connected, a scene of color changes on a plane can be created, which is richer and more gorgeous than the usual control of color flow on a line. This controller uses a digital integrated block, with few peripheral components and a simple circuit structure. As long as the components are intact and the connection is correct, it can be successful without debugging after installation.

This article uses the two-dimensional color light control signal flow as a clue, analyzes the basic working process of the relevant digital integrated circuit, and introduces the production process of the two-dimensional color light controller according to the requirements of electronic assembly process. I hope this article will be of some inspiration to students of electronic technical schools and electronic enthusiasts to understand and become familiar with the application of digital circuits.

How the Circuit Works

The two-dimensional colored light controller circuit is shown in Figure 1, which is mainly
composed of the NOT gate IC1 (CD4069), the counting/timing distribution circuit IC2 (CD4017), the analog electronic switch IC3 (CD4066) and the D trigger IC4 (CD40174).

The logic function and pins of CD4069 are shown in Figure 2a, where the NOT gates F1, F2, external resistors R2, R3, and capacitor C4 form a multivibrator, which generates a pulse square wave of about 3Hz, which is supplied to CD4017 as a counting pulse and CD40174 as a shift pulse. R3 and C4 are oscillation timing components. Adjusting these two components can change the frequency of the oscillation signal, thereby controlling the flow speed of the color of the colored lights to present various visual effects. In addition, the NOT gate 3 of CD4069 is also used as an inverter for the reset signal of CD40174.

CD4069 is a CMOS digital integrated circuit, a high input impedance device, which is easily disturbed by external interference, causing logic confusion or induced static electricity to break down the gate of the field effect tube. Although the device has a protection circuit set up at the input end, they have limited ability to absorb transient energy. Excessive transient signals and excessive static voltage will make the protection circuit ineffective. Therefore, the input ends {9}, {11}, {13} of the unused NOT gates F4, F5, and F6 in CD4069 are all connected to the Vss ground terminal for protection.

The pulse train sent from the output terminal {4} of the CD4069 multivibrator is directly sent to the count pulse input terminal {14} of the CD4017. The CD4017 is a decimal counter/timing distributor, which is used to generate the control signal for the switching of the CD4066 analog switch. Its pin function is shown in Figure 2b. Cr is the reset terminal. When the Cr terminal inputs a high level, the counter is reset to zero. The CD4017 has an automatic start function, that is, when the circuit enters an invalid state, it can return to the normal cycle after a maximum of two clock cycles under the action of the count pulse. Therefore, the CD4017 of this controller does not have a power-on reset circuit. Co is the carry output terminal, and a positive pulse is output when the count reaches 10 clock pulses. The CD4017 has two count input terminals, CL and EN. The CL terminal is the pulse rising edge trigger terminal. If the count pulse is input from the CL terminal, the EN terminal should be connected to a low level; the EN terminal is the pulse falling edge trigger terminal. If the count pulse is input from the EN terminal, the CL terminal should be connected to a high level, otherwise the count pulse is prohibited from being input. The counting pulse from CD4069 is input from its CL terminal {14}, so the EN terminal {13} is grounded. Y0~Y9 are the ten output terminals of the counter. The pulse square wave sent from the output terminal is connected into two control signals through isolation diodes VD3~VD12 and added to the analog switch CD4066.

When the first counting pulse arrives, the circuit inside CD4017 flips, and the {3} pin Y0 is high level, which is added to the {12} pin of CD4066 through the diode VD5. CD4066 is a bidirectional analog switch, and its pin function is shown in Figure 2c. It contains four independent analog switches A, B, C, and D. This controller uses two switches B and D. Each switch has an input and an output, and these two ends can be used interchangeably. The input terminal {11} of switch B is connected to the power supply and connected to a high level; the output terminal {8} of switch D is grounded; because the two switches are connected in series, the output terminal {10} of switch B is connected to the input terminal {9} of switch D, as the switching point between high and low levels. In addition, the {12} and {6} pins of CD4066 are the selection terminals of switches B and D respectively. When a high level is input, the switch is closed; when a low level is input, the switch is open. Switch B, under the action of the high level input at its strobe terminal {12}, connects {11} and {10}, and {10} becomes high level. At the same time, the other output terminals Y1 to Y9 of CD4017 are all low level, so the strobe terminal of CD4066 switch D is also low level, and switch D is turned off, which does not affect the level state of {10}.

The high-level signal output from the {10} pin of CD4066 is directly sent to the serial input terminal {3} pin of the D flip-flop CD40174. CD40174 contains 6 D-type flip-flops, as shown in Figure 2d. This controller connects 5 of them into a five-bit shift register with serial input and parallel output. Among them, D6 is the highest bit flip-flop, and D2 is the lowest bit flip-flop (D1 is not used), arranged in sequence. Each flip-flop has its own input and output terminals. The output terminal Q of the higher bit flip-flop is connected to the input terminal D of the lower bit flip-flop. Only the input terminal CD40174 {3} pin of the highest bit flip-flop D6 receives the pulse signal. CD40174 {2}{4} pin, {5}{6} pin, {7}{11} pin, {10}{13} pin, {12}{14} pin are the connection points of the input and output terminals of each adjacent flip-flop, respectively, as the parallel output terminal of the five-bit register. The reset terminals of each flip-flop are connected together as the total clear terminal of the register. The low-level reset is effective before the register works. The reset signal should jump to a high level at the start of work and remain during the work. The reset signal is provided by the reset circuit composed of capacitor C3, resistor R4 and CD4069 NOT gate 3. At the moment of power on, the power supply voltage is differentiated into a positive pulse by C3 and R4. This pulse is inverted by NOT gate F3, output from CD4069 {6} pin, and sent to CD40174 reset terminal {1} ​​pin to complete the zeroing task before the register works. As time goes on, C3 finishes charging and forms a stable low level at its negative terminal, which is inverted by F3 to meet the needs of the register during work. The clock pulse input terminals of each trigger are also connected together as the shift pulse input terminal of the register.

The shift pulse is taken from the pulse train of the CD4069{4} pin and input from the CD40174{9} pin. At the rising edge of the first shift pulse, the high-level signal input from the CD40174{3} pin is shifted into the trigger D6, and the output state of the register changes from the initial "00000" to "10000", and the CD40174{2}{4} pin is high. This high level is added to the transistor VT1 through the isolation resistor R11 to be amplified, and then output from its emitter and sent to the control electrode of the bidirectional thyristor VS1, driving VS1 to turn on, and the first colored light is lit due to its current loop. At the same time, the remaining four output ends of the register are all low-level, and the bidirectional thyristors VS2~VS5 are blocked without driving signals, and the four controlled colored lights II, III, IV, and V are not lit.

When the second counting pulse arrives, the CD4017 counting output terminal Y1 is at a high level. This high level is output from its {2} pin and added to the CD4066 {12} pin through the diode VD4. Keep switch B turned on, thereby maintaining the high level state of the serial input terminal of CD40174 {3} pin. Under the action of the second shift pulse, the output state of the register changes from "10000" to "11000", and the CD40174 {2}{4} pin and {5}{6} pin are at a high level, which is amplified by the transistors VT1 and VT2, driving the thyristors VS1 and VS2 to turn on. In this way, while keeping the first colored light on, the second colored light is lit one after another, and the remaining three colored lights are still off.

When the third counting pulse arrives, the CD4017 counting output terminal Y2 is at a high level. This high level is output from its {4} pin and added to the CD4066 {12} pin through the diode VD6. Switch B continues to be turned on, and continues to maintain the high level of CD40174 {3} pin. The third shift pulse changes the output state of the register from "11000" to "11100", and CD40174 {2}{4} pin, {5}{6} pin, {7}{11} pin are at a high level at the same time, and the transistors VT1, VT2, VT3 drive the thyristors VS1, VS2, and VS3 to conduct. The colored lights of the first and second routes continue to light up, and the colored lights of the third route are lit again.

Similarly, when the fourth and fifth counting pulses arrive, the counting output terminals Y3 and Y4 of CD4017 are high level in turn. CD4066 keeps switch B on, and the 4{3} foot of CD4017 maintains a high level state. The fourth and fifth shift pulses make the output state of the register "11110" and "11111" in turn. On the basis of controlling the lighting of the first three colored lights, the thyristor lights up the fourth and fifth colored lights in turn.

It can be seen that the five colored lights are lit up in increasing order row by row.

When the sixth counting pulse arrives, the CD4017 counting output terminal Y5 is at a high level. This high level is output from its {1} pin, added to the gate terminal {6} pin of CD4066 switch D through diode VD3, connecting {8} pin and {9} pin, so that {9} pin is grounded. At the same time, the rest of the counting output terminals of CD4017 are low level, and CD4066 switch B is turned off to prevent the power supply from being short-circuited by the connected switch D. Since the {3} pin of CD40174 is directly connected to the {9} pin of CD4066, the serial input terminal of the CD40174 register becomes low level. Under the action of the sixth shift pulse, the output state of the register changes from "11111" to "01111", and the {2}{4} pin of CD40174 outputs a low level, and the transistor VT1 is turned off. The thyristor VS1 loses the trigger signal and blocks itself at the moment when the AC power passes through zero, and the first street light goes out. The high levels of the remaining four output ends of the register continue to control the lighting of the four colored lights II, III, IV, and V through VT2, VT3, VT4, VT5 and VS2, VS3, VS4, and VS5.

When the seventh counting pulse arrives, the CD4017 counting output terminal Y6 is at a high level. This high level is output from its {5} pin, added to the {6} pin of CD4066 through the diode VD7, and the {9} pin is kept grounded. To maintain the low level of the serial input terminal of the CD40174 register. The seventh shift pulse changes the output state of the register from "01111" to "00111", and the {2}{4} pin and {5}{6} pin of CD40174 output low levels at the same time, and the transistors VT1 and VT2 are cut off. The thyristor VS1 maintains its blocking state due to the lack of trigger signal; VS2 is blocked at the moment when the AC power supply passes zero due to the loss of trigger signal. The colored lights of the first and second channels are turned off. The high levels of the other three outputs of the register still control the lighting of the colored lights of the third, fourth, and fifth channels.

Similarly, when the eighth, ninth, and tenth counting pulses arrive, the high levels outputted by the counting output terminals Y7, Y8, and Y9 of CD4017 control the connection of the switch D of CD4066, and maintain the low level of the serial input terminal of the CD40174 register. When the shift pulse input terminal of the register receives the eighth, ninth, and tenth pulses in turn, the output state of the register is "00011", "00001", and "00000", respectively. The low levels of the 3rd, 4th, and 5th bits control the thyristors VS3, VS4, and VS5 to be blocked in turn. When the colored lights of the first and second paths are turned off, the colored lights of the third, fourth, and fifth paths are turned off in turn. The above description shows that the five colored lights are turned off in a row-by-row decreasing manner.
When the counter CD4017 counts 10 pulses, its carry terminal {12} pin outputs a positive pulse, which is directly fed back to its reset terminal {15} pin, resetting the counter, and then starting the next round of counting process, so that the colored lights work in a cycle.

The resistor R1, capacitors C1, C2, diodes VD1, VD2 in the circuit form a power circuit. The AC220V mains electricity is converted into a relatively stable DC12V low voltage through the power circuit's voltage reduction, rectification, filtering and voltage stabilization, providing working voltage for each transistor and integrated circuit.

Controller production

1. Assembly of printed circuit boards

After being familiar with the component models and specifications and testing the performance of the components, the printed circuit board can be assembled. The printed circuit board is shown in Figure 3.

The assembly of printed circuit boards is the key to successful production. In order to achieve better results and smooth boxing, the process requirements are as follows:

Integrated circuits, resistors, and diodes are installed horizontally. The VDD terminal of the integrated circuit is connected to the positive pole of the power supply, and the VSS terminal is connected to the negative pole of the power supply, that is, the integrated block must not be inserted in reverse, and care should be taken to avoid the phenomenon that its pins are not fully inserted into the jack. When forming the pins of resistors and diodes, they should be bent 1.5mm from the root of the pins to prevent the leads from breaking; the devices should be installed close to the printed circuit board. Capacitors, transistors, and thyristors are installed vertically. The capacitor pins are not formed and can be directly inserted into the jack for welding, but the bottom of the capacitor should be close to the printed circuit board, otherwise its height will cause inconvenience to the box installation. The height of the bottom of the transistor and thyristor device body from the printed circuit board should be 2 to 3mm to facilitate heat dissipation. When welding, ensure that there is no leakage, cold welding, overlapping welding, etc. at the solder joints. After welding, the excess part of the pins should be cut off, leaving the head 0.5 to 1mm above the welding surface, and the welding surface should not be damaged.

2. Connection between printed circuit board and five-link power socket

On the soldering surface of the printed circuit board, the pads c, d, e, f, and g connected to the thyristor electrodes T1 are connected together with insulated wires, and then connected to the pad a at the power supply.

Disassemble the five-link power socket, solder off the power cord, and disconnect the original connections of each reed. Solder five insulated wires from the five reeds on the same side of the power socket, and then connect the other ends of the wires to the Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅴ pads on the circuit board in turn. Connect the reeds on the other side of the power socket together, and then use a wire to connect their common point to the b pad at the power supply. After connecting, straighten the wires, lead them out from the threading hole, and install the power socket.
The power cord is a two-strand wire, one end of which is connected to the power plug, and the other end is suspended. Solder the two ends of the suspended end to the L and N pads of the printed circuit board respectively.

3. Packaging of printed circuit boards

Take an empty plastic box with a size of not less than 100×75×15mm, make a threading hole at an appropriate position on the side of the box, cut a piece of green paper with the same area as the printed circuit board and pad it on the bottom of the box, then place the circuit board in the box with the components facing up, and use 502 glue to slightly fix the inner wall of the box and the edge of the circuit board, lead the wires out of the threading hole, and close the box cover. In this way, the printed circuit board is encapsulated in the box. Use of the controller

Colored lights use small bulbs with a voltage of 220V and a power of 5W to 25W. Due to the power limit of the bidirectional thyristor, the total power of each street lamp should not exceed 300W. If more complex patterns are combined and more bulbs are needed, thyristors with a larger rated forward average current can be selected. Colored bulbs can also be replaced by colored light strings of corresponding power.

When in use, just plug the power plugs of the five-way colored lights into the sockets of the controller combination socket respectively, and then plug the power plug of the controller into the AC220V socket of the mains.