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Laser Alarm for Protecting Field Crops against Animals

The post explains a simple laser alarm circuit which can be installed in farms and fields for detecting all possible intrusions, either by a human or an animal and alarming this to the owner, and ensuring an effective protection to the crops against such intrusions. The idea was required by Mr. Mohammed and Mr. Daniel.

Circuit Request#1

Congratulations for all amazing work please give me any circuit for agricultural fields, need to protect the crops from uninvited guests like animals i want to achieve an Active infrared barrier [laser] circuit with distance range of 100 meter or above.

mohammed jilani Mansoori

Circuit Request#2

sir please my grandfather is an orange farmer and he is having a problem with thief's so he ask me to do something that to protect the farm or anything that can alert him when any thief's or any person try to take away any thing from the farm so i decided to install a CCTV camera,so i need a circuit without a camera or if you can help me out sir i have said this but you can create something that can help me out thank you hope to hear from you soon

Daniel Adusei

Simulation and Working

Laser Alarm for Protecting Field Crops against Animals

 The Design


The proposed laser alarm circuit for protecting crops from animals and intruders can be seen in the figure above.

The idea appears extremely straightforward, and employs an IC 555 based monostable multivibrator stage and an LDR detector.

As shown in the design, the laser beam is generated through a laser pointer circuit held at some parallel point across the field fence which requires to be protected.

Since a laser beam has the property of focusing over a given point undistorted and on a straight line, regardless of the distance, the focus in this application is adjusted over an LDR across a specified distance, as indicated in the diagram.

The LDR is enclosed inside a light proof box with a tiny hole which allows only the laser beam to enter while obstructing most of the ambient light around.

As long as the laser beam is held focused over the the LDR, the resistance of the LDR is enabled at a minimum level which could be around 10K to 50K approximately depending on the particular LDR specs.

The low resistance from the LDR ensures a high potential at the base of the associated BC557 transistor rendering it inactive. This in turn keeps the pin#2 of the IC555 monostable at a high potential and the output of the IC at logic zero, so that the relay is held switched OFF.

Now in an even when an intruder (a human or animal) makes an attempt to cross the protected line of fence, cuts or obstructs the laser beam, which instantly causes the LDR resistance to increase and trigger the BC557 device via the 1M resistor.

The BC557 responds to this and conducts grounding pin#2 of the IC and activating the monostable action.

The above procedure forces the pin#3 of the IC to go high and switch ON the relay, the relay contacts possibly being connected with an alarm, sounds the alarm, alerting the field owner regarding the intrusion.

The alarm continues to sound for some moment of time depending on the values of R and C, whose values are directly proportional to the length of the alarm switch ON period.

The above discussed laser alarm circuit can be installed across all the corners of field for ensuring maximum and all round protection for the valuable crops and for ensuring a peaceful sleep to the field owner.

Need Help? Please leave a comment, I'll get back soon with a reply!




Comments

  1. Nice idea sir. You resolved the huge problem by simple circuit

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  2. Thank you Vijay, I am glad you liked the concept!

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  3. thank you sir for your kindness am very happy sir i build it but it don't operate i use laser sir can i use 12v dc to power it cos that is what i did

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  4. Daniel, first check the resistance of your LDR separately with a meter, by focusing the laser ON/OFF...the LDR value should vary between 10K (on laser light) and 2meg (in darkness)

    confirm this first then we can proceed further...

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  5. Thank you so much sir i buld it but not good perfomance some time work and sometime not work i used ldr 10k to 900k (i want to delay time 1-10 minute wich pre set used and where)

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  6. why no good performance???

    may be you did not focus the beam correctly, or may be you've used bad quality parts, or may be the LDR enclosure is not adequately light proof...the problem could be somewhere in your construction...check it properly.

    you can set the ON time by referring to any online "555 calculator software"

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  7. i have made this circuit and in place of alarm i use a mobile phone which gets me an automated call on my cellphone

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  8. that's interesting?! thanks for updating!

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  9. sir i want to start an startup , related to manufacturing of electronics products at small scale, and for this i need to buy machines,like soldering pot chemicals and many more things that will be needed in pcb making, pcb asembly, driling cutting. Etc so plzhelp me by giving the address of store where i could buy all of these. Plz.,

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  10. Hussain, you can visit Lamington Road in Mumbai and get everything that you need related to electronics....also make sure to visit lohar chawl for the same....

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  11. good day sir
    how can make the alarm ringing continuous once an intrution happens and then later can reset
    thanks
    john

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  12. Hi John,

    you can replace the 555 circuit with the following shown transistor circuit for getting a continuous alarming

    https://homemade-circuits.com/2011/12/simple-and-useful-transistor-latch.html

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  13. ....or use the last circuit shown here:

    https://homemade-circuits.com/2013/02/make-these-simple-cheap-home-burglar.html

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  14. good day sir
    thanks for the immediate reply . sir can tell me what kind of scr to be used ( spec of scr )
    john

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  15. John, you can any standard 1amp SCR, but I did not recommend the SCR circuit rather the one which uses two transistors.

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  16. Sir, this circuit is prefarable for shop protections, sir, LDR has any value? because my shop is 10-11 sq.ft. any change is required in this circuit?
    If any change is required, please tell me which value LDR , AND Other component is required for properly work .

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  17. Arun, as long as the laser is able to reach the LDR, distance or area will not be an issue.

    A good LDR will have a value of around 10K to 50K in ambient light that is during daytime, outdoors, but under shade.

    so you can test it practically...however any LDR that satisfies the circuit setting up conditions will work

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  18. HI swagatam thanks for all your effort and innovations, now before i integrate this circuit to alarm system, help me about how to connect a buzzer to the relay because it has + and - where is + connected and - . thanks very much and think i will secure my garden

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  19. Thanks Davis, connect the center pole with the (+) supply, connect the N/O with one wire of the buzzer and connect the other wire of the buzzer with the (-) supply.

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  20. Dear sir I have done this circuit on board for my peddy field but alarm ring only for 5 sec , can u plz guide me to make it for 2to 5 min

    Thanks

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  21. Sidhesh, Increase the 1M value to 2M2, this will increase the delay to 10 seconds

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  22. Thank you very much sir , it's working

    Sir I need one more circuit with small memory in it so the I can upload human voice , this will make a human presence when wild animals come to farm to make them afraid

    Thanks

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  23. That's good Sidhesh, you can try the following chip for the recording application

    https://homemade-circuits.com/2017/05/audio-recordplayback-circuit-using-ic.html

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  24. Thanks sir ,
    It's working but but siren is not working at that great sound but when I cannot at just normal battery, it is working but through circuit sound is bit slow I checked volatg out put 11.5 volt, but different battery it's working but same battery it's not , so what do you suggest me

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  25. Or sir can u give me any circuit throught which I can connect multiple dc devices

    Thanks sir

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  26. Hi Sidhesh, the alarm will be normally a high current device, therefore it will require a separate high current supply to operate correctly, otherwise it might fail to generate the required loudness...

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  27. Ok sir but how should I connect laser diode, LDR circuit, siren on one single battery , do I have to build seperate circuit so that I can connect multiple devices , it's 12v 7 ah battery

    Thanks for ur help 21

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  28. Sidhesh, I think 12V 7AH is actually powerful enough, and can drive any siren with full volume, and therefore you can use the battery for operating the circuit as well as the horn together...make sure the horn you are using is actually in proper working condition...

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  29. ..and remember you must use a relay or a BJT driver for operating the horn, you should not connect the horn directly with the IC 555.

    and also make sure the laser is rated to work with a 12V supply.

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  30. Sir,
    Please i am very interested to construct your laser projects, now my only dificulties is that, where i am i cant fine the laser touch, please sir can you give me help on how i can construct any laser pointer using a VCD or DVD lense?
    please i wait your response.
    thanks for understandings.

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  31. Nkwenti, I have no idea how the laser from a DVD can be used here, so I won't be able to help you much regarding this issue....

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  32. My problems is the touch .... But thanks for the reply n the good job you're doing

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  33. But any idea how a laser touch can be home made....I only need a laser touch

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  34. sorry I have not yet investigated it, so have no knowledge about it at the moment...

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  35. Hi sir, I have tried to design a laser sequrity alarm, please check the design and suggest me corrections, its not working.

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  36. Hi sir I have tried to design a laser sequrity alarm, please check it and suggest corrections as it's not working
    https://plus.google.com/+AbhishekSharmatechperson/posts/Uqo9LbDViU5

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  37. I can only discuss about the above shown circuit, did you build the above circuit? It will definitely work because it is so simple...

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  38. Hi sir, I would have made it earlier but this doesn't have latched activation, means when laser interrupted the buzzer is ON and keep ON till reset button is not pressed even when light comes back. That's why I was trying to make one with latched action.

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  39. Hi Abhishk, for latching you can simply build the last circuit presented in the following article:

    https://homemade-circuits.com/make-these-simple-cheap-home-burglar/

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  40. Sir, where i connect alarm

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  41. Pranay, If your Load is DC rated then you can wire it with the relay contacts and the positive supply line.

    for more details you can read this article

    https://www.homemade-circuits.com/how-a-relay-works-in-circuits-how-to-connect-it/

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  42. Hi, can I use this circuit to control water pump which is around 400 feet away from the water tank or can you suggest me a wireless remote switching circuit.

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  43. yes this concept can be effectively used but only if the laser beam is able to reach the LDR

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  44. I very glad when I read this article. This one project I really like, this is because most rice farmers in Ghana suffer losses and have to spend man-hours to keep intruders away. I would like to build one and apart from the laser source can work with LED source.
    Thanks
    Philip

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  45. I am glad too you liked this article, LED might not work, since its range accuracy and intensity is far less than a laser beam

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