Online repair manual

Here is an straightforward name bell circuit that displays a welcome message when anyone presses the call bell switch momentarily. the alphanumeric show can be fitted close to the call bell switch. the circuit is built round two 555 ICs (IC1 and IC2), seven KLA511 common-anode alphanumeric shows (DIS1 through DIS7) and some discrete elements. For simple understanding,  the entire circuit may also be divided into  two parts: controller and show. the controller part is built around  IC1 and IC2, whereas the show part is constructed round alphanumeric displays (DIS1 via DIS7). 

As exhibitn in the circuit, each IC1 and IC2 are wired as monostable  multivibrators having time periods of round 5 2ds and a pair of minutes, respectively. You can change the period of time of IC1 by altering the worths of resistor R12 and capacitor  C3. Similarly, the time period of IC2  can also be changed via changing the values of resistor R2 and capacitor C1. Alphanumeric displays DIS1 through DIS7 are wired such that they show ‘WELCOME’ when the output of IC2  goes excessive. the circuit is energyed by way of a 6V battery. Else, you can use the 6V, 300mA energy adaptor that is quite simply on hand in the market. the 6V battery or energy adaptor offers regulated 6V required to operate the circuit. 

Call Bell with Welcome Indication Circuit Diagram

 

A 6V DC socket is used within the circuit to connect the output of the adaptor when you don’t use the battery. Working of the circuit is understated. First, energy-on the circuit the usage of change S2. LED1 glows to level presence of energy provide in the circuit. Now if you press name bell change S1  momentarily, it triggers  each the timers (IC1 and  IC2) simultaneously. IC1 produces a high output at its pin three for approximately five 2ds. transistor t2 habitss and piezobuzzer PZ1 sounds for approximately 5 2ds indicating that there is  somebody on the door. At the identical time, IC2  too produces a high out-put at its pin 3 for roughly two minutes. transistor  t1 conducts to allow the alphanumeric shows. the word ‘WEL-COME’ is displayed  for about two minutes  as DIS1 through DIS7  floor via transistor T1.

If swap S1 is pressed again within these two minutes, piezobuzzer PZ1 once more  sounds for five seconds and the display continues to point out ‘WEL-COME’. Assemble the total circuit on a normal purpose PCB and home in a small cupboard with name bell change S1 and LED1 established on the entrance panel. At the rear facet of the cabinet, join a DC socket for the adaptor. Install the total unit (along with the show) on the entrance of your home. Connect the 6V battery or 6V adaptor for energying the circuit. Configure swap 2 (used to allow/disable the decision bell) in a switch board at an acceptable region inside of your home. If you don’t use a battery, connect the facility adaptor to the DC socket on the rear of the cupboard. Close switch S2 most effective when you need to have to prompt the circuit with  battery. Otherwise, preserve it open when the 6V adaptor is in use.

1. To avoid any shorting  right via rain, waterproof all the circuit meeting including alphanumeric shows (installed on the entrance) with the help of masking it properly.

2.  the total package for this circuit is to be had with EFY affiliates  packages’n’spares. 

Author : S.C. Dwivedi - Copyright : EFY