DIY Seismic Sensor

[febalci]

Hi all,

Living in a highly active earthquake zone, i decided to look for a seismic sensor. Looking at all the available options, i found out the Omron D7S seismic sensor is just the sensor I was looking for (http://components.omron.eu/Product-details/D7S). It is really very very tiny:





D7S is working on i2c protocol. SDA and SCL provides instant earthquake and its power data whereas INT1 provides emergency situations like SHUTOFF (like gas valves, electricity switches etc) or COLLAPSE.

Since i did not wanted to deal with PCB board or smd components, i needed to solder 5x2 cables to smd size pins:



I really needed to have a magnifying glass and not shaky hands for this soldering. Than i thought there must be an easier way. I bought this 1.27mm male and female pin headers:




In order to have a communication with Domoticz i decided to use ESP8266 for that. But for prototyping Adafruit Huzzah was easier, so i assembled everything on breadboard:




And again luckily, i found this Arduino Library for D7S (https://github.com/alessandro1105/D7S_Arduino_Library) , thanks to Alessandro Pasqualini...

And it works perfectly... I am in the process of designing a PCB board on Eagle; if there is anyone interested i would be more than happy to share my work.

[gert3d]

Interesting, do you have any results yet? I mean: what movement can be noticed?
From the datasheet I see that you need an earthquacke above Richter 5 to get a signal. This is a rather firm earthquacke....

[febalci]

Actually it is not 5 on Richter but 5 on Japan Seismic Intensity Scale, since this sensor measures SI and PGA values, the ground velocity, not the Richter scale. So, comparison might not be true in some sense. 5 on Japan refers to : Hanging objects swing. Most unsecured objects topple. Cupboarded dishes and shelved books fall; furniture moves. Where PGA is between 0.80–1.40 m/s² .

I did not lived an earthquake since i installed it (and hopefully never live , but the sensor is not catching up regular (truck passing) vibrations. Hence its main duty is to shutoff valves and/or electricity during a serious earthquake or read collapse data. SI value is giving more precise values on intensity according to structure and building conditions instead of Richter; and SI is comparable to Japanese Seismic Intensity Scale. It simply gives the average value of the shaking velocity. And almost all gas and other plants use SI sensors for preventing earthquake related damages.