help,urgent!!

door announcer!

hey,i wanna dsign a cicuit where when people entry or exit,the siren will sound(mostly can find shop).anyone know how to design or what components in needed.thanks

One way to do it.

The IR Mini Alarm will alert you to anyone going into a monitored area.

Doorbell sound to detect visitors, switch to siren to detect intruders.

Doorbell sound lets you know the delivery person enters the back door or a customer has entered the front door. Alarm Siren let people know (and you) that they are in a restricted area or an intruder is in a protected area. All done with the IR Mini Alarm.

Small enough to be put most anywhere and battery operated so there are no wires to run. The passive IR sensor provides the most reliable form of detection 24hrs a day
Position can be adjusted through 120° following installation. Unique, compact, portable, can be mounted on a wall or placed on a desk and easy to install.
Dimensions: 2.6" x 4.1" x 1.4". Power supply: DC 4.5V (3 AA batteries not included)
Detection area: max. 32ft / angle 89°. Switch positions: (1): chime-ding-dong (2): off (3): alarm-siren is activated for 40 seconds and is automatically reset afterwards. battery life: approx. 120 days (detection only), operating temperature: 14°F to 104°F. Accessories: mounting bracket, screws, wall anchors.

# HAM9011 $19.65

**broken link removed**

I have this idea how to make this out of old vhs players:

There is a IR detector and sender that detects when the casette is on place. Problem is that IR detector is also sensitive to regular light. One way to solve this is to modulate the light source with some frequency, and on the receiver there shall be a bandpass filter.

Another thing to do that might improve the detection rate (not from regular light source) is to put both sender and receiver in tubes, pointing toward each other.

If you are lucky, you only need to buy screw driver, solder, solder iron and a versatile print board (doesn't know the exact name for this). There should be plenty of hf transistors inside any vhs player.

And please change topic (Read PM)

thanks to you all