thebaldgeek

Made the last physical change to reduce the urban noise this past weekend.
We did a speed read of the USGS seismic vault construction guideline, you can pull it down and check it out here; https://pubs.usgs.gov/of/2002/ofr-02-0144/ofr-02-0144.pdf

In short, they recomend a bunch of things that I cant come at, either size wise, or cost wise.
We tried to take the guts of the vault and reproduce it in the backyard.

One thing to note from the recommendations, we don’t have to worry about the thermal aspects of the vault since the Raspberry Pi seismograph is not adversely affected by temperature changes.

This is the big picture. We are going to dig a hole, put some cement in the bottom, stick the plastic bucket into the hole – grounding it in the wet cement – then put some more wet cement in the bottom of the bucket, then put a plate (USGS said glass, bit short on that so using some steel) on the cement and that’s hopefully that.

So, lets get going…..

Hole dug, and wet cement in the bottom.
As per the PDF, we put a mound in the middle then pushed the tub down and settled it.

It probably did not matter much, but we made sure it was level in both directions.
The USGS said that we should put wet cement around the whole bin, but I was short on cement, so we just left it at the bottom. We could get some more and put it around the whole thing at a latter date, but, well, lets see how things go with just the bottom stuck down.

Wet cement in the bottom, the plate on top and leveled in both directions.

The Raspberry Pi setup is the same. I did not feel the need to change anything in this regard.
The Ethernet brings both network and power. The POE adapter splits it off and routes it to the appropriate port.

The fake rock is just sitting there for now, but the plan is to dig it in a little around the edge, put some sort of edging around to ‘seal’ the ‘rock’ to the ground and thus tub.
We are planing a small garden around the corner of the retaining wall, both to ‘hide’ the rock a bit, but also to finish that part of the lawn, the grass never grows all that great, probably due to the grape fruit tree shade.

The fake rock and tub are not the best, I like the seal on the old bucket better, but it was just too small and shallow. We could not find a longer one with the same seal, so we just have to make do.
The big issue is bugs. A close second is water/moisture.

So, the 300 dollar question, how is the urban noise?
Duno. Its only been in place a few hours Sunday afternoon, we need to watch it for 2-3 days at the very least to get a feel for things.
Don’t forget that you can view its almost live output here; https://thebaldgeek.net/index.php/seismograph/

What’s in the bucket?

I started out with the seismograph sitting on my desk over night and yeah, it was a mess. Every footstep, every movement of the mouse, it picked it all up. I (thankfully) don’t have any screenshots of that trace. Trust me, it was totally and completely unusable.

Next I tried the concret floor of the garage.
It would pick up every time the garage door opened and closed and you could see Martty drive in and out.
And yeah, since you didn’t ask, it would pick up the bass of every Trance rave we had……

I put it on the back patio for a bit. Eh. It was okish.
Honestly it was too close to the house wall. If I chased Malcolm down the stairs, it would pick it up, so it was not ideal, but it was better than in the house or in the garage.
So, that said, it sat there for a good month or three.

Next up, we read that really you need to build a seismic vault for the things….. Sure, perfect would be sweet, but I ain’t got the time, money or space for perfect, so what’s the next best thing?
Stick it in a bucket.

Here it is out in the front garden.

Not much to look at really.
It’s a plastic bucket with a screw on lid buried to the level of the top of the bucket.
Trouble is, out the front garden, it picked up the next door neighbours washer / dryer…..
Less than desirable.

Here it is in the backyard.

And this is where it is as we type.

So whats in the bucket?

A Pi and the power over ethernet adaptor.
The Pi needs 5 volts DC at about 2 amps to run, I don’t want to have to run two cables out there, network and power, so you can buy these adaptors that put about 24v on the network cable at the head end and then step what ever is left down to 5v at the Pi end.
Thus, one cable doing both jobs.
Very handy.

Here is the whole show close up.
And yes, it’s not perfectly level here. That is part of the problem with the bucket, the Pi moves around a bit and it is not dead nuts level, so I have been popping the bucket lid every 2 weeks or so and making sure it is level…. The bucket was never a long term solution, so I did not bother with making it more stable in the level department…..

Ok, so that is what is in the bucket.

Bottom line. I am still not happy with the amount of urban noise I am getting, so Dad and I are brainstorming a smaller / cheaper seismic vault.

Watch this trace.