Tag Archives: PIR sensor

Motion Sensing Pumpkin Vibrobot

Mechanical Engineer and K-12 STEM educator, Ben Finio, has designed this kid-friendly motion sensing pumpkin Bot, which could be a fun project to make for the next Halloween. The thing I liked the most about this PumpkinBot is its simplicity and microcontroller-free design. His motion-sensing bot uses a passive infrared (PIR) sensor attached in front of the pumpkin to detect motion. Three toothbrush heads are glued underneath the PumpkinBot to give it a stable tripod. When a motion is sensed, it triggers the robot’s LED eyes and a DC motor attached on its back. A wine cork fixed to the motor shaft create vibrations that are strong enough to move the robot around. It works best on a flat and smooth surface. You can leave it on your porch and watch enjoying the PumpkinBot scaring trick-or-treaters as they approach to your door.

Motion sensing pumpkin robot

Motion sensing pumpkin robot

Make your own motion sensor alarm with SMS feature

MikroEleketronika demonstrates how to build a simple home alarm system that has the capability of sending SMS to a predefined cell phone number when intrusion is detected. This project is based on StartUSB for PIC board, a small development board for PIC18F2550, which is preprogrammed with an USB bootloder so that no additional programmer is required to load the firmware. The SMS portion uses a SmartGM862 Board, which is a full-featured development tool for the Telit’s GM862 GSM/GPRS module. All the boards required for this project can be purchased as SMS Home Alarm Kit from mikroElektronika. A demonstration software for PIC is also available for free. They are offering free shipping now.

DIY home alarm kit

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555 Contest Entry: Motion activated camera

This entry for the 555 timer contest is from Andrew Smith who built a motion activated switch for a digital camera. The 555 timer is operating in monostable mode which is triggered by a PIR sensor when motion is detected. The monostable output of 555 then activates the camera through a remote.

Motion detection alarm using a PIR sensor module with a PIC Microcontroller


This project describes a motion sensor alarm based on a Passive Infra-Red (PIR) sensor module. There are many vendors that manufacture the PIR sensor modules and almost all of them are pretty much the same in function. They have a single output that goes high (or low, based on specification) when the motion is detected. In this project, a PIC12F635 microcontroller continuously monitors the output from the sensor module and turns a buzzer on when it goes active.


Certain crystalline materials have the property to generate a surface electric charge when exposed to thermal infrared radiation. This phenomenon is known as pyroelectricity. The Passive Infra-Red (PIR) sensor module works on the same principle. The human body radiates heat in the form of infrared radiation which is maximum at about 9.4 um. The presence of human body creates a sudden change in the IR profile of the surrounding that is sensed by the pyroelectric sensor. The PIR sensor module has an instrumentation circuit on board that amplifies this signal to appropriate voltage level to indicate the detection of motion.

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