Category Archives: raspberry pi

The Oscar Detector


I have always used the cat and turtles as catalysts for different projects. I thought this would be a good one because I hadn’t done much with the raspberry pi camera that I had, and I also wanted to work on using the GPIO pins on the raspberry pi to read sensor data.  This was another good project to practice writing code in python on the pi.  The concept: detect the cat, take his picture, tweet his picture (@KookieHouse). Continue reading The Oscar Detector

Garage Sensor and Remote

This post is one in a series of posts relating to my home automation project. My setup is based on the Uber Home Automation instructable by elecetronichamsters, found here.

IMG_20150426_173318 IMG_20150426_173313

This is one of the more exciting nodes I’v gotten working so far. Late last year, I left the house for a hockey game, and when I got home I found that I had left the garage open the whole time. Having a monitor on it is useful for alerts if the door is open for too long, and being able to close it remotely if it’s accidentally left open is even more useful. I used this as a catalyst for figuring out how to trigger actuators (a relay in this case) from openHAB. It was a very slow and painful process but it’s really cool to have working now.
Continue reading Garage Sensor and Remote

Door Sensors

IMG_20150405_165148 IMG_20150405_013926

This post is one in a series of posts relating to my home automation project. My setup is based on the Uber Home Automation instructable by elecetronichamsters, found here.

The first two nodes I created were simple door sensors. The sensor is just a reed switch attached to the door frame and a magnet attached to the door. When the door is closed, the magnet pulls the reed switch closed. When the door is open, the switch is open. It doesn’t get much simpler than that. Additionally, the node measures the voltage from the battery. Every time the door opens or closes, the status is sent wirelessly to the openHAB server.

wiring diagram for door switch

The program that runs on the arduino is interrupt driven, meaning that the arduino is in a very low power sleep mode until it detects a signal. This allows the batteries to last much longer. Once the signal is detected, it evaluates the state of the switch and communicates that to the server. The program can be downloaded from my Github repository here.

The openHAB configuration is very straightforward. It updates the interface based on the state of the switch. I decided to use the “contact” mapping rather than the “door” because I liked the graphic better. I also added a feature to see the last time the status was updated by clicking on the individual doors. Finally, on any state change, I receive an email from openHAB alerting me of the change. The email is routed directly to a specific label and marked read so I am not bombarded with status updates, but it is nice to be able to see the history of each node without having to go any further than my gmail account. The email is sent using an openHAB rule.

doors timestamp

These nodes use moteinos with RFM69HW chips preinstalled, which can be purchased here, and reed switches which can be purchased here. The battery packs, wires and small breadboards are all easy to find. I also use a liberal amount of velcro.

These nodes are a great place to get started if you are considering doing this project. The program is very simple and is simpler still if you don’t use the interrupt.

Making Our House Smarter


A few months ago, I came across an instructable explaining how to make a DIY home automation system using arduinos and a raspberry pi (two things I have previously written about). The instructable, which can be found here has morphed into an entire community of people who have created systems in their own homes. In the process, there are several improvements that people have been able to make since the original system was described. Because there are so many people working on this and many of them have questions, a whole forum was created which is dedicated to these sorts of questions and ideas (found here).

Continue reading Making Our House Smarter