2-line 10-way Digital Display Pager: Traditional Chinese Circuit Desig

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Two-line ten-way digital display pagerCurrently, pagers used in hotels, inns and wards mostly use lights to display the calling room. When the service staff hears the call and forgets the order of the lights, they have to check the location or look at the number next to the lights. Although it is intuitive, it is still inconvenient.The two-line ten-channel digital display pager is clear at a glance. The service staff hears the call sound and the room number is displayed digitally at the same time.The pager has a simple structure and is suitable for hotels, hotels and hospitals. When the number of calling rooms exceeds 10, a digital display circuit is added, and the number of rooms controlled can be up to 99. It is introduced below for interested units or individuals to copy.1. Circuit working principleThe control circuit of the two-line ten-channel digital display pager is shown in Figure 29-1. It is composed of a pager switch and a level driver integrated circuit.The internal circuit of the domestic level driver integrated circuit SL322 is shown in Figure 29-2.Figure 29-2According to the internal circuit of the level driver integrated block SL322, it can be seen that the output signal voltage of each output terminal is output in sequence as the input voltage increases. In this way, as long as a voltage-reducing resistor with different resistances is connected in series to the call switch in each room, the call signal from the room can be output and the corresponding digital display circuit and alarm circuit can be triggered.If you press K1 to add voltage to pin ① of SL322, the first signal voltage is output on pin ③ and is sent to the base of BG1 tube through diode D1 and resistor R23, causing the audio complementary circuit composed of BG1, BG2, C2, R24 and Y to oscillate and alarm.At the same time, the signal voltage triggers the digital display circuit and displays "1"; when K2 is pressed, "2" is displayed while the alarm sounds, and so on.Figure 29-3The digital control circuit, as shown in Figure 29-3, is composed of matrix diodes, unidirectional thyristors and light-emitting diodes. The control poles of the one-way thyristors are respectively connected to corresponding diode decoding circuits. When no trigger signal is added to terminals 0 to 9, the light-emitting diodes on each thyristor circuit do not light up, and there are no numbers displayed on the display. When a trigger signal is added to a certain terminal, the corresponding decoding circuit works, triggers the corresponding thyristor, and displays the corresponding number. For example, when the "1" terminal is programmed with a trigger signal, the two diodes on the 1-1 line and the c-c line and g-g line are turned on, triggering the corresponding silicon controlled thyristors SCR3 and SCR respectively, causing the light-emitting diodes controlled by SCR3 and SCR to light up and display the number "1".The digital display is shown in Figure 29-4. It is composed of 20 light-emitting diode segments. The diagram is divided into abcdefgh8 segments. Each segment is equipped with 2, 3 or 4 light-emitting diodes according to the length of the stroke. Several light-emitting diodes on each segment are connected in parallel, so that the digital display has the same brightness. When one or several light-emitting diodes are damaged, partial display can still be performed. As can be seen from the figure, when the light-emitting diodes on segments a, b, d, g, and h light up, the number displayed is "5".Table 29-1 Number of segments lit by each digitDigital\lit segments1\c,g2\a,c,d,f,h3\a,c,d,g,h4\b,c,d,e,g5\a, b, d, g, h6\a, b, d, f, g, h7\a,c,g8\a, b, c, d, f, g, h9\a, b, c, d, g0\d,b,c,f,g,h2. MakeThe diode decoding circuit is best made of a double-sided copper-clad board. One side of the copper-clad board is corroded with 10 vertical copper foil lines such as 1-1 and 2-2, and the other side is corroded with 10 horizontal copper foil lines such as a-a and b-b. Then drill holes according to the arrangement of the diodes and solder the diodes. The light-emitting diode can also be directly mounted on the board in the shape shown in Figure 29-4.Figure 29-4The appearance of the two-line ten-channel digital display pager is shown in Figure 29-5, and it can be made of metal sheets or other materials. The size of the housing is based on the size of the pager's movement, digital display and 12V or 9V battery.Figure 29-5In order to make the digital display clear and accurate, the shell facing the digital part should be drilled with holes of corresponding width and length according to the length of the digital strokes. Any space between the strokes (that is, they do not belong to the same segment) should be retained and cannot be dug out to avoid interference from adjacent segments. Then stick a piece of milky white or other light-colored plexiglass or frosted glass on the outside to make the digital display soft and harmonious.For the part where the speaker is installed, a number of sound-emitting holes should be drilled on the box body, and a power switch for the pager should be installed on the box surface.When in use, place the installed pager box on the wall inside the counter of the duty room and turn on the power switch. Whenever a call is made, the power switch should be placed in the off position and then turned on again to ensure that the next call can work normally. …

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