This is the final part in the series of articles (parts 1, 2, 3) about building a remote home monitoring system based on Arduino. Lessons learned The monitoring task I’ve had was unusual enough to justify building my own system. For more typical tasks, like monitoring the inside/outside temperature, it would be much easier to buy a relatively inexpensive thermometer with a PC interface. Overall cost of the built system is in the ballpark of some $150-170 – still way below what the commercial systems cost (especially with multiple sensors and flood detection) When it comes to the power consumption, commercial consumer electronics sensors are way more efficient. A typical temperature sensor can run on a couple of batteries for many months, whereas an Arduino-based device would have to draw AC power. Wireless communications are painful 🙂 I am yet to look into the message corruption issues…
Ideally, it would have been nice to use some kind of sockets to be able to connect and disconnect the sensors but I didn’t bother with this for now. At the end, I settled for the following:
- DS18B20 is soldered directly onto the shield
- The thermistor is extended using the two-wire 24-gauge speaker cable (as it needs to run through the crawlspace window outside) which is soldered directly onto the shield
- DHT22 temperature/humidity sensor is also soldered directly onto the shield, as it doesn’t need to go to far
- As for the eTape sensor, I ended up using 4-pin JST SM cable. Doing it all over again, I probably would’ve used the speaker wire as well, as only to wires are needed.
In part 1 I have looked at the options available for the task of remote climate monitoring and settled on Arduino-based solution. In this we will discuss the design of the system.
The high-level architecture is typical for Arduino: there is an Arduino-based board that collects the sensor data and passes it over USB to the PC that processes this data and uploads it to the database. A more parsimonious solution would be to build an Arduino board with an Ethernet or Wi-Fi shield and to connect it directly to the network, but I already had a tiny Atom-based PC (NetBox nT-535) running 24×7 and doing other tasks. Plus, Arduino library is fairly limited, so doing any more or less sophisticated data manipulation right on Arduino is difficult.
Since I needed to monitor 3 different locations (outside, crawlspace, and indoors), I could either run wires or work out some kind of wireless solution to communicate the data from different places. Wired solution is easy electronically but requires drilling holes and running wires around the place which is not fun. A good solution would not need that, so wireless was indeed the answer. In this case, I could do away with running 2 Arduinos: one sitting in the crawlspace and collecting the crawlspace temperature, outdoor temperature, checking the water level on the ground, and sending all this data to the “master” Arduino board that collected the indoor temperature and sent all collected data to the PC via USB.
Being a paranoid person, I always wanted to monitor our summer house remotely. With all the advancement of technology, one would think such a task is easy these days but surprisingly it is not. Off-the-shelf systems look like they are still stuck in the 80s and no one has bothered to build an open and modular system for such a purpose.
In the coming several posts I’ll describe the system I’ve built for my own purposes. Hopefully, this would be helpful for the next guy trying to do the same.