If you are looking for a countdown timer we will built it here in few minutes. So in this project we will built a timer. So, How to make 30 Minutes timer at home in easy way. This project will be a very simple and useful. Defiantly you can built this project at home on your weekend. DIY lovers should love this project idea. This 30 minutes timer cab be use in many and different ways, so let’s get started to built.
- 1 Video
- 2 Tools Required
- 3 Parts Required
- 4 Steps to built 30 minutes timer
- 5 Circuit Diagram
- 6 Project you may Like
- Screw driver set
- Soldering Iron kit
- Multi meter
- Utility Knife
- Marker and Pencil
- Hole Punch
- Hot Glue Gun
- Vero Board or Blank PCB
- Card Board
- Panel type female banana pins (2 Nos.)
- 6 way rotary switch with knob
- 12 Volt Female Connector
- 12 Volt Power Supply
- 555 Timer IC
- 8 Pin IC Socket
- Push Button
- 47 uF 25V Electrolyte Capacitor
- 0.01 uF Ceramic Capacitor
- 4.7 K Resistor
- 47 K Resistor
- 12 V 1 C/O Relay
- 1N4007 Diode
- BC 548 Transistor
- Hook up wire
- 1.2 Mega Ohm Resistor (2 Nos.)
- 3.3 Mega Ohm Resistor
- 5.6 Mega Ohm Resistor ( 2 Nos.)
- 15 Mega Ohm Resistor
Steps to built 30 minutes timer
Selection and Cutting Vero Board
- In this project we have to built a custom circuit It may not available in market. So we are using a vero board in this project. In the vero board widely available in two variants, there is major different on back side. One is coming in Dot type board and second comes in short track type on back side. The vero board used in this project is Dot type on back side. As shown in above video we take full vero board and we will cut it as per it’s need.
- As we discussed in previous topic, the vero board which we are using have no tracks. So we are making tracks on back side of PCB on lower side and upper side as shown in this image. Reason to make tracks on back side of PCB, It is easier way to design circuit. We are making tracks using soldering Iron on back side of PCB.
Placing 8 pin IC socket and it’s connections
In this project we are using a 555 Timer IC, But we will not solder 555 timer IC directly to the circuit board. Reason why direct heat of the soldering iron may damage the IC. So the use of socket is safer way to protect IC from the direct heat.
- Solder 8 pin IC socket in the center of the circuit. Make sure that pin 1 and pin 8 are facing to the positive track of the circuit. And solder it with the circuit board with carefully.
- Solder pin 8 and pin 4 (Reset) to the positive track. Solder pin 1 to the ground track,
- Solder pin 5 to the ground connection via 0.01 uF ceramic capacitor.
Trigger or Start Push Button
- We are using a push button to start a timer circuit.
- Connect 47K ohm Resistor to the pin 2 of the IC.
- Connect Start push button between pin no 2 and ground connection.
Connection to the Rotary switch
- Short pin no 6 and pin 7 of IC.
- Connect 47uF electrolytic capacitor between pin 6 or 7 and ground connection.
- Now we will arrange the rotary switch connections.
- Solder 1.2 Mega ohm resistor to the pin 1.
- Solder 1.2 Mega ohm resistor between pin 1 and 2.
- Solder 3.3 Mega ohm resistor between pin 2 and 3.
- Solder 5.6 Mega ohm resistor between pin 3 and 4.
- Solder 5.6 Mega ohm resistor between pin 4 and 5.
- Solder 15 Mega ohm resistor between pin 5 and 6.
- Then solder positive connection to the 1.2 Mega ohm which is connected to the oin 1 of the rotary switch.
- Next solder pin 7 of the rotary switch to the pin 7 or 6 of the IC.
Output and Relay Connections
- Pin 3 of the 555 timer is the output connection of the IC.
- We are using a BC548 transistor as a switching transistor, By using transistor we will switch on and off relay.
- Where we are using 1 C/O 12 volt relay.
- The base pin of the transistor is connected to the pin 3 of IC via 4.7K ohm resistor as shown in circuit diagram.
- Solder Emitter pin of the transistor to the ground connection. Collector pin of the transistor connected to the positive terminal via relay coil connections.
- We will connect fly diode parallel to the relay coil connection as in circuit diagram for protection of the relay coil.
- This project is powered by 12 Volt power supply. We will solder 12 volt power supply to the positive and negative track of the circuit,
- Also high voltage electrical switching connection connected to the 12 colt relay, Between Common and NO (Normally Open) connection.
Make sure preform this project in expert’s supervision. Before connecting electrical load to the relay connections first read user manual of the relay.
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