Here is a 555 timer circuit project. You can use it for the snooze alarm with a buzzer. When on time 5, 10, 15, and 30 minutes or even 1 hour. It is easy to make and portable with small PCB.
If you want to control other loads. It is easy with a relay directly. Because an output of 555 has maximum current to 200mA.
How it works
When we turn on switch-S1 to enter a power supply to the circuit. It will be ready to go. The parts have a different function.
The circuit includes IC1-555 Mono Stable (timer) for the delay.
Switches S3 S6—choose a time as we want
- If turns on S3 for 5 minutes. Then, turn off the S3.
- To turns on S4 for 10 minutes. Then, turn off the S4.
- Next, turns on S5 for 15 minutes. Then, turn off the S5.
- Last, turns on S6 is scheduled for 30 minutes.
This project use principle of monostable multivibrator 555. It works with a delay charge and discharges completely. When in time that setting. It will send a signal to Pin 3 is low. But can power buzzer-BZ1 beeps out.
The time value is determined by the value R2, R3, R4, R5, and C2. If you want to set up a long time, it increases the R and C. The time is short. If it reduced the R and C.
How to build this project
This project is very easy. Because of use a few components. As shown in Figure 2 is PCB layout and the component layout.
You must be careful about some devices with terminals. For example, IC-555, Electrolytic capacitors, and buzzer. They will are connected to match terminals only.
Figure 2 is PCB layout and the components layout
This project worked my son test it on the breadboard. Below!
He tests at 5 minutes.
Adding Relay to control more
If you want to control more load. It is an easy way with helping of Relay. Look at the image below.
This is simple universal timer projects. You can use a relay to connect with the buzzer. To control other loads that you want.
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