How to install IR Security Sensor in vending machine?

Discussion in 'General Electronics Chat' started by md40022, Aug 12, 2016.

  1. md40022

    Thread Starter New Member

    Aug 12, 2016

    My apologies in advance, but I'm not the most technical person. Hopefully someone can help me though.

    My company sells and supplies vending machines and one of our customer's is having a problem with his employees sticking a knife into the area of the machine where the product is dispensed in order to pry products out of the machine without paying for them. I know a surveillance camera is the obvious solution here, but our customer said he cannot do that for whatever the reason might be. He is wanting us to come up with some type of Infrared Sensor that would sit in the passage way where the product is dispensed from, therefore triggering some type of horn or siren when the employees stick the knife into this area.

    The passage way in this machine is fairly wide open, so installing a trasmitor and receiver for the IR should be very possible as far as having enough room for the sensors, but nobody in our shop is electronically knowledgeable enough to know how to pull this off.

    The obvious catch here is when someone actually puts money into the vending machine to legitimately buy a product then that IR would need to shut off at that point for the alarm did NOT trigger when purchases were made, but only when people tried to steal from the machine by sticking this knife into the passage way and prying out the product.

    There is a circuit board in the machine where we can tap into for powering the IR & siren/horn, but again the catch here is when someone purchases a product the IR would need to be disabled. I'm having trouble attaching photos to this thread, so below is a link to a site where I uploaded 2 photos. One photo of the circuit board in the vending machine and one photo of the electronics drawing. There is a J-2000 Coin Mechanism in the machine which accepts the customers payment and once the proper money amount is satisfied I would imagine switches are opened or closed on the board, allowing the customer to make the purchase. Upon that switch (or switches) opening or closing we'd like to have that disable the IR for paying customers weren't triggering alarms. Basically we would like to have the IR Alarm constantly active with the exception being we want it to disable when a customer puts payment into the machine to buy product.

    I do have the print at home with me so I can take close up photos if more info is needed, but any help with instructions on how to do this project would be very much appreciated. And again, nobody in our shop is overly technical with electronics, so if this project is doable please provide as much detail as possible as far as what parts are needed, etc.


    Link to the 2 photos - circuit board and circuit board print -
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    Surely it would make more sense to fix the problem by mechanical means than for someone who has no access to the machine or detailed knowledge of its design to guess how it works so that they can explain to someone thousands of miles away who doesn't know what they're doing how to wire in something that probably won't work and may cause damage.
  3. md40022

    Thread Starter New Member

    Aug 12, 2016
    Forgive dumb questions here, but does the circuit boards print drawing now give some of that info? We have a 24v constant line and numerous N/O switches that close when payment is entered into the machine.

    This is a customer who owns a chain of restaurants and provides a lot of business for us. We are trying to do what we can to accommodate him. In my limited knowledge this seems to be a doable project.
  4. BR-549

    Well-Known Member

    Sep 22, 2013
    Let me see a picture of where he sticks the knife in. Close up and back away. Also picture inside machine where knife comes in.

    We need to mount a knife detector with an alarm.
  5. md40022

    Thread Starter New Member

    Aug 12, 2016
    Here is a link to a photo of the machine model.

    Just below the logos of the different laundry detergents you'll see a horizontal slot. That is where the product drops to once purchased, and that is where the employees a sticking this knife and prying out the product without paying.

    The doors above the vend buttons swing open and there is a circuit board and coin mechanism installed on the right side door. There is plenty of room there to tap into any wiring on the circuit board as needed.

    The area directly behind the logos of the laundry detergents is wide open and should have plenty of room to install a transmittor and receiver for an IR.

    ** I am not in the shop anymore. I will be back on Monday morning and can take photos of specific things if needed at that time. Hopefully this is enough info...... We do have a whole shop of machinists who will have no problem properly installing the sensor(s) or whatever is needed...... It's mainly the electronics aspect that we are clueless on.