Saturday, October 13, 2018

Spin Cycle

The days are noticeably shorter here than when we arrive--just like everywhere else in the northern hemisphere, haha. Here's a photo of the sun just lighting up the building this morning on Calle San Jorge, the street parallel to us between here and the river:

Pretty quite, not too many folks about.


Relatively normal day. Laura and I went grocery shopping. Had to do the usual big Saturday shop since everything's closed on Sunday. Laura found some bacon, so we tried BLTs for lunch:

Even added a bit of guacamole. Tasty.


I continued to play around with the vibration sensor on my phone. Today I did a load of laundry. Our little washer can do a spin cycle that will knock your socks off (or at least get most of the water out of them, haha). The washer claims, right on the front, that the drum spins at 1200RPM. I've always thought that was amazingly fast. I realized today that I have the tools to test that claim. I recorded the vibrations of the washer during the spin cycle, did a Fourier transform on the data and made this heatmap:

If you look closely, you see that the frequency of vibration tops out at about 19 Hz at around 6 mins into the spin cycle. That's 1140RPM! Not 1200RPM, but close enough. The step pattern of the trace is also interesting. It ramps up to 5 Hz, spins for a while, then ramps up to 16.5 Hz, spins for a while, then up to 19 Hz, and spins for a while before dropping a back down to 0 (which is below the resolution of this technique). I'm not sure what the constant 3 Hz vibration is. Maybe the water pump. These phone sensors are a lot of fun. Now I'm obsessed with finding things to measure.


This evening I sat by the river and read a bit. I noticed this very orange orange in a nearby orange tree with the bridge providing a nice backdrop. So, I took a picture: