Seismograph - Steampunk Edition

The pendulum seismograph is an instrument that responds to ground vibration like earthquakes, explosion's etc. and was invented in the 1700's, this is my version of a X/Y-axis type in steampunk design. This is a practical teaching aid in addition to a decoration (with optional lighting) and a conversation piece. The seismogram you see recorded on the white roller on this model is a real actual recording of ground vibration's, not an earthquake, but seismic activity equivalent to a 2.3 magnitude earthquake recorded on 23.07.2023 in Seattle during Taylor Swift's "Eras" concert at Lumen Field. As there are many different functions on a seismograph model I have numbered a picture and explained each part in the text below.

Model information

• 2x standard LED tea light candles can be inserted inside the white roller to create nice ambient lighting
• The feet are adjustable, but the model does not write
• All parts are printed except for the string, i have used a shoelace
• Size when assembled: ca. H26 cm x D30 cm

Printing

• Make sure you have good bed adhesion, clean print bed and calibrated filament
• Let the parts cool down before carefully removing supports. Some of the supports are a bit fiddly to remove, but pliers do the trick
• 0.2 mm walls
• 15% infill in all parts except for 100% on the weight and pen
• Various types of support. I recommend using the setup for support and orientation in my print profiles
• Tested and printed in PLA

Assembly

• Glue the non moving parts together, the parts only fit one place, look at the images if you are uncertain where they go
• The seismogram graph prints in two parts, slide it on to the roller rotate the parts until you find the ones that are more or less a mirror of each other and glue them together, orient it with the side you think is nicest up and glue it to the roller. Be very careful when working with these as they are very thin and break easily.
• Attach and glue the roller drum to the main pipe before you attach the main pipe to the base.
• If you are going to have tea lights in it, don't glue the side opening on the roller.
• Adjust the height of the weight so that the pen hit the roller and don't slide out of the weight.

How a seismograph / seismometer works

A seismograph measures ground vibration's in 3 axis, X, Y and Z. This type measures X or Z, you use 2 similar instruments and orient one on each axis. The Z version measures up and down movement and writes the seismogram vertically instead of horizontally like this one. A pen is hanging in a heavy weight and when the ground vibrates, the pen and weight hang stable in one place, but the rest of the seismograph will move, including the rolling drum with paper on it. When the drum moves from the vibrations underneath, the lines are drawn on the paper, the result being a seismogram. There are lines on the paper to identify time.

Parts of the seismograph

These numbers reference the picture with numbers on it.

1. The feet. These are adjustable so that the unit can be set level. Level it using the feet so that the pen is hanging in the center of the roller.
2. The rotating drum and paper (the one on this model does not rotate). This part rotates with paper around it and the lines are there to tell when and how long the vibrations last. This is called a seismogram.
3. The string. This is suspended so that it can only move back and forth in one axis / direction.
4. The weight / pendulum and pen. This remains steady during vibrations and the pen marks the movement on the paper.