How to Make DIY Security Alarm Device with a Reset Button | DIY Project
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- Опубликовано: 1 авг 2017
- How to build a simple security alarm system with a reset button.
This device is based on a simple flip flop circuit.
How it works:
If you move the magnet from the reed switch or if someone cuts the wires that go to the reed switch, it will trigger the alarm. Also, you can pull thin wire and connect to this device, and if someone breaks the wire it will trigger the alarm also.
How to reset:
After the door closed/wire connection restored - circuit became closed, is so then you can press the reset button and reset this alarm.
What you need to build this device:
- 4 transistors BC547B.
- 6 resistors 10K.
- 2 resistors 1K .
- A button for reset.
- Active 12V buzzer.
- A reed switch.
- Magnet.
- Wires.
Powering:
Any DC power source from 5 to 12 volt.
(better use power supply, because when the device is ON it always consumes some energy)
If you don't need reset button functionality, you can build a lot simpler circuit, watch this video: • DIY Tripwire security ... 
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Great video! Keep up the good work!
Just built the circuit. It works like a charm! What a fun and useful circuit!! Thank you very much for sharing.
Good circuit best
Great video. Thank you for this set up. I've been looking for a schematic like this using transistors for a while now and I came across your video. Thank you again. Have a question though, can I run a stronger siren (car alarm siren) to the buzzer leads? I didn't know if this set-up could support a car alarm siren.
thanks sir
Good
Can i use these circuit with 3 pin Ir receiver?
do u have a pcb design for this circuit?
How much is the power consumption?
I mean, for how long can it remain activated using 9v battery if not triggered?
sir its nice project but i have question if door open for prolong time like 1 hour and during this time if i reset alarm i want buzzer stop buzzin how can is achive? if yes how please reply me?
This is just what i am looking for, nice job. The only problem is that i want more noise. i wanted 30 whats so the theef gos running like hell. Haw do i do that? Or is it possible. Thx for info man
Hello, yes, it is possible. You can use a relay. Just connect the coil of a relay in paraben to the buzzer or instead of the buzzer, and with a relay, you will be able to control anything.
can i bulid basic flip flop circuit without resistor? (use transistor (bc547B) , led only (for fun)) . i try to build a circuit without resistor but two led switch on .
Hi, without some resistors you will probably burn BC547B or LED or both. Well, flip-flop circuit requires resistor, and nothing we can do about it. Is it really difficult to find some resistors nowadays? It is not necessary to use exactly the same values. Just teardown some old TV, or radio, and you will have plenty of resistors.
pleas I need gold detractor easy make with diagram
can I use LDR at next end (Reed switch) to use it as burglar alarm pls help me
Hi, but why LDR? are you trying to build a laser alarm? Or do you want to use a beam of light? Tell me more about your idea.
If you just need a laser alarm then check this video, it is probably what you need: ruclips.net/video/MD1nsqO_WGE/видео.html
How to power voltage
hello，can i use MOSFET transistors 2n7000 to replace bc547b?
Hello, I haven't tested it in real life, but I did a simulation in Proteus.
Here is what I found out: the circuit stopped working after I replaced transistor Q1 with 2N7000 MOSFET.
So far I can say that transistor Q1 should be BC547B.
But It will probably work fine if you just replace Q2, Q3, Q4 with 2N7000 (it works in Proteus simulation), but it will not work if you replace Q1 with 2N7000.
P.S. Sorry for my late reply.
thank you ,
Hi can u help me pls for my project, if i want to change the reset button into a bluetooth reset directly alarm to my cellphone, how can i connect the the bluetooth reciever??? Pls help
Hi, it is hard to help here, not enough information. Do you speak about some particular bluetooth reciever? what outputs does such receiver have?
Hi. Have done your circuit and it works well. The only thing is the buzzer (12V) have not enough power to buzz loud. If I connect only the buzzer with battery, everything is fine (loud)( but when it turn on within the circuit, the sound level is too low. Any suggestion?
Hi, it is strange... You probably use a pretty powerfull buzzer... try to add one more 10K resistor in parallel to R8 (or just replace R8 with 4.7K resistor) but this most likely will not help you.
Do you use 12V to power everything?
How powerful buzzer do you use? how many mA does it consume? The buzzer that I show in the video consumes less than 15mA at 12V.
If you use more powerful buzzer than I show in the video, I recommend to replace Q4 with IRF540N, then you will be able to connect even 100W buzzer without any problems. Tell me your results.
The buzzer is 50W so somewhere around 4.2 A. as describe on the internet ad. I haven't tested it yet. Base on that, did changing the resistor is a solution or is it better to change the transistor?
WOW, that explains everything. Q4 BC547 transistor can only handle 0.1A so you definitely need to use IRF540N.
How to replace: IRF540N and BC547 have different pinouts and different names for pins. See those "B", "C", "E" letters on the circuit diagram near Q4, those mean "base", "collector", "emitter". But IRF540N has "G", "D", "S" - means "gate", "drain", "source". So you need to connect "gate" instead of "base", "source" instead of "emitter", and "drain" instead of "collector".
How to know which pin is which: just google "BC547 Pinout" or "IRF540N Pinout". It would be nice to know about your results. Goodluck!
Also, consider adding a small heatsink to your IRF540N, if it gets very hot. If your buzzer is really 50W then IRF540N will produce about 1W of heat.
Maybe I can salvage a c4662 transistor. What do you think?
Hi
I tried your circuit its ok but
after every 4 minutes it automatically on's the buzzer
solution please
I used with ldr and lazer
Hi, try replacing resistor R1 with 20K, or even 47K and test it again.
can you please tell its working principal theoritically ? its urgent!
Hi, just google and read about flip-flop circuit, because this device is based on it.
is it posible to use ldr and laser security in it
Hi, I have not tried it, but I think it should work... but you probably will need to replace R1 (10k) resistor with 20k - 50k resistor.
P.S. In case you try it, tell me your result, please.
@@ElectricalPro Can use this circuit with 3pin IR reciever?
I have made this alarm but my alarm is not reset by push button ...... instead of push button what can i use ?
Or Can u explain this circuit theoretically how it works ?
Hello, this device is based on flip-flop circuit. Starting from 03:31 to 4:07 I show what flip-flop circuit can do (flip-flop circuit remembers state). You can read about flip-flop circuit on Wikipedia or just google it. Are you sure that the reset button is a problem? Maybe, the problem is the reed switch? Try to connect wires that go to the reed switch together, and then try to reset this device with the reset button. Tell me about your results.
P.S. sorry for late response.
I have made this circuit on bread board. When i'll given suppy voltage then buzzer in on and if i press push button it will not work, so can u tell me what's the problem in that ?
You need to do some diagnostics to find out what is wrong.
First test: disconnect resistor R8, after you disconnect resistor R8, the buzzer should stop making noise. If your buzzer after disconnecting R8 still making noise it means that transistor Q4 is dead and you need to replace it with a new one. (if after the test you know that Q4 is fine then connect R8 back again and do the second test).
Second test: this test will test the flip-flop circuit (in other words Q2 and Q3 transistors). Watch how to do this test from 03:31 to 4:07. To do this test you need to disconnect transistor Q1 (see I only using Q2, Q3, Q4).
Use a wire with a 10K resistor (watch 03:38), and do a test (watch 03:50). Flip-flop circuit should turn your buzzer on and off, just like on my video. If it still only always on then replace Q2, Q3 with a new transistor.
I hope it helps you.
Ok thnks
Thanks sir,please send me your Facebook profile or page link
Nice video keep up with good job! I make the same kind of videos! Hope you check out my channel!
Bilkul bekar
Great video! Keep up the good work!
Good