Summary of MotionMote – Moteino motion sensor
MotionMote is a low-power, wireless motion detector designed for home security using a Moteino node and a PIR sensor. It operates without wires, utilizing a 9V battery and an acrylic enclosure laser-cut at Techshop-Detroit. The device sleeps indefinitely to conserve energy, waking only upon motion detection to send an alert message and light an LED.
Parts used in the MotionMote:
- Moteino node
- PIR sensor
- 9V battery
- Low power red LED
- Acrylic case
- Laser cutter settings (speed:20, power:90, freq:5000)
I’m calling it MotionMote because it detects motion and because pretty much every type of wireless sensor or Moteino node name ends in “mote“.
The possibilities for home security are endless, put this little guy in a corner near a door or on top of a cabinet somewhere and detect them intrudaz! Did I say there’s no wires?
Read on for details and source code and case design.
Nothing very complicated about it. I waited to post about it since I didn’t have any casing and I thought it would be nice to enclose it in a nice white acrylic case. I laser-cut a few at Techshop-Detroit using MakerCase. The inside case dimensions are: 59mm long, 29mm wide, 33mm deep, the PIR sensor diameter is 22.5mm. The tab size is maximum (5mm) and material thickness 3mm (1/8″). All other MakerCase settings are default. The laser cutter settings are speed:20, power:90, freq:5000. I started out with wood because there’s always plenty of scraps around and easy to find the right dimensions, then moved to acrylic:
The schematic/wiring is trivial. The PIR sensor has 3 pins – GND, VIN, and OUT. It can take anywhere from 5V to 9V or even more. I used a 9V battery since it’s pretty compact. Later I want to try using lipos with a Moteino shield I am working on, more about it in another post. The OUT pin goes high for a specific length of time when motion is detected (adjustable by side pot, I turned mine to minimum to limit LED power consumption). The sensitivity is also adjustable by another small side pot. The wonderful thing is that this PIR sensor is very cheap (commonly found on ebay for a few bucks) and uses about 60uA when idle and about 200uA when active! Coupled with a low power LED for visual indication the overall power consumption is very low. Of course the Moteino and everything on it has to be put to sleep. The OUT pin is connected to a low power 2mA red LED and to the hardware interrupt INT1 (digital pin D3 of Moteino). This way the sketch sleeps indefinitely, and when motion is detected the LED lights up and Moteino wakes up and quickly sends an ACK-ed “MOTION” alert message.
For more detail: MotionMote – Moteino motion sensor
- How does the MotionMote detect motion?
The PIR sensor OUT pin goes high when motion is detected, triggering a hardware interrupt that wakes the Moteino. - Can I adjust the sensitivity of the sensor?
Yes, the sensitivity is adjustable by a small side pot on the PIR sensor. - What voltage can the PIR sensor accept?
The PIR sensor can take anywhere from 5V to 9V or even more. - How much power does the PIR sensor use when idle?
The PIR sensor uses about 60uA when idle. - What happens when motion is detected?
The LED lights up and the Moteino wakes up to quickly send an ACK-ed MOTION alert message. - Is it possible to enclose this project in a case?
Yes, the author laser-cut a white acrylic case with specific dimensions to enclose the components. - Where can I find the source code and case design?
The article mentions details and source code are available via the link provided for MotionMote. - What material was used for the final casing?
The author moved from wood scraps to using acrylic for the final case.
