Download Free 3D Model Animalarm – a sensor to control pet movements 3D Print Model

Summary
A simple but elegant project to create a “pet zone alarm” in your house. It uses infrared motion detectors to sense when a pet (or small child) is moving through a doorway or hall and sends out a loud tone. It does not beep when a (tall) person moves through the same area. With a bit of training animals recognise where they are welcome – without having to use physical gates.
NOTE: WIP – Some electronic component values are subject to change
Post-Printing
Caveats
Obviously, you will need to be able to get the PCB manufactured. The files are all there to do so and it is very cheap. And of course you need the skills and equipment to source and assemble the electronics!
If you want to use a different buzzer, you will need to make your own shell – but the electronics at least will work for you… Application
There is a single trimpot to set the length of the beep, once the alarm is triggered. You can also change component values (C1 in particular) to alter the delay before the alarm goes of before triggering the alarm. Set it longer if the system is triggering falsely.
There are pads in the 3D print design at the top and bottom of the Animalarm. Use double sided tape or bluetack at those locations to mount the alarm on the wall / doorway.
How I Designed This
How this works
The Animalarm uses two PIR (passive infrared) detectors to detect and discriminate between pets and people. The detector needs to be mounted on a door / wall about a meter above the ground. One PIR “looks down”, the other “looks up” to detect motion. A pet only triggers the lower detector and sets of the alarm. If a person is detected, the alarm either never triggers or is shut off.
The circuitry is built around a single CMOS chip and a few transistors – and of course battery, buzzer and PIR detectors. The circuitry is incredibly power efficient, drawing less than 30µW normally and only 10mA when triggered. This means the batteries will probably last a year in normal use… Electronics
The attached files include:
the Eagle design files (schematic and PCB)
Circuit schematic
PCB layers images
Gerber files for the PCB to be produced by seedstudio.com
List of special components and their sources
All the components are incredibly cheap; the PIR detectors are less than $2, the circuit board less than $1; indeed the most expensive component is the buzzer. The total component cost is about $15 (printed shell aside)