Seismograph
Introduction: Seismograph
Professional quality seismograph, fully open source, based on a Raspberry-Pi, with 1 to 4 components, able to record earthquakes or other seismic events, either natural (rock fall, glacier movement) or man made (train detection, vehicle detection). The seismograph works either autonomously in the field, or can be used as an Iris seismic station recording mini-seeds and uploading to an Iris server. Able to run an Apache web server accessible in 1 click from anywhere in the world and displaying the last 48 hours of recorded seismic activity. The 1 component version is under under $100 and the 3 component version under $160, to be truly accessible to schools or institutions in developing countries.
Once the supplies are available, the build is very fast: about one hour.
Home page: https://erellaz.com/blog/seisberry/
Supplies
* One Raspberry Pi. I recommend the Raspberry 3 B Plus over the Raspberry 4, as the enhanced video features of the Raspberry 4 are not needed for the seismometer application, while the Raspberry 3B+ has about 20% lower power consumption and is cheaper than the Raspberry 4.
* The Waveshare High precision AD / AC board board for Raspberry.
* Geophones. At least 1 vertical, optionally 2 horizontal geophones. For seismic I use 10Hz phones, which are also the cheapest ($30): 1 Vertical and optionally 2 Horizontal components. For seismology I recommend geophones with a lower frequency, like 4.5Hz: 1 Vertical and 2 Horizontal components. Alternatively you could get 3 omnidirectional geophones. Omnidirectional geophones may be a little bit less sensitive, but with them you do not have to worry about setting your recorder horizontal. You can order from RT Clark in Oklahoma, or you may try your luck and find equivalent products on Aliexpress. The RT geophones come with their shunt resistor already soldered. If you get your geophones from other sources, read the doc and get matching shunt resistors (probably something close to 395 Ohms).
* Stranded wire, 20 gauge, ideally red and black. 18 gauge (which is a bigger wire than 20, that’s how gauge works) will barely fit in the AD bus. 152
22 gauge is too small.
Step 1:
* Download and install Balena Etcher, or an equivalent. This assume you are using a Windows PC.
* Download this Seisberry Image (Raspbian Buster with various libraries installed, and compiled code, about 8G). The latest version, dated August 24 2020 is called “Cotopaxi”. It has GPS support and various enhancements, as well as a GUI. You may find older/experimental versions in this directory, which should not be used: stay with “Cotopaxi”.
* With Etcher, burn the Seisberry image to your SD card (needs to be a 16G SD minimum). The distribution should expand to your card size on install. Put the card in the Raspberry internal bay.
* Either plug a screen + keyboard + mouse to the Pi OR download and install VNC viewer on your PC and connect the Pi to you network with a network cable. Then in VNC viewer log to the host “seisberry16Hz”, user: pi, password: seisberry. If you do not have a proper DHCP server on your network (rare now) you may have to plug a screen to the Pi once, type ifconfig in a terminal, and write down the Pi’s IP. Then use that IP in VNC viewer for the Host name.
Step 2:
* On the Pi: immediately change the password in Start>Raspberry Pi configuration.
* Optional: update your Operating system. This may take a while. Open a terminal and type:
sudo apt update
sudo apt full-upgrade
* Shut down the Pi when done.
* Set the jumpers on your AD board as in the picture (top right, yellow jumpers).
* Connect the board to the GPIO of the Raspberry, and put the 2 screws and spacers coming with the board.
* Solder the wires to the geophones. I use about 6 inches of wire. Geophones are polarized, so the red goes on the + and the black on the -.
* Connect the geophones to the board, as in the picture (G1 is the vertical component).
Step 3:
* Power up the Pi.
* If your external card is not called 32G, you need to edit the following text file: ~/Desktop/DIYSeis/C/param, and change the target of the script accordingly. 611