This is a great and easy project to do for starters and experts

You will need a -screw driver
-NC or NO reed switch
-9 volt battery
-9 volt battery clip
-3 jumper wires
-active buzzer
-breadboard

Step 1: Step 1

Put the active buzzer on the breadboard

Step 2: Step 2

Connect the positive pin of the buzzer to com on the reed switch

Step 3: Step 3

Connect the negative pin in the buzzer to the negative rail on the breadboard.

Step 4: Step 5

Connect the positive rail on the breadboard to N/C or N/O depends if you want the buzzer to buzz when the door opens if so connect to N/C, if you want the buzzer to buzz when the door is closed connect to N/O.

Step 5: Finish

Now connect the battery clip to the positive and negative rail on the breadboard then plug in the battery and test. You. Can mount this to a door I used blue tack but you can use whatever. If you liked this please like it and also if you need some active buzzers I have some on this link right below.

Active buzzers- http://www.ebay.com.au/itm/182557930221?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649