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Author Archives: gregorykimball
Montague Paratrooper
My new bike is here! I decided to get a Montague Paratrooper, because it is the only full-size folding mountain bike on the market. I was looking for a reliable bicycle that would also store conveniently in the trunk of my car.
USB toggle switch extension
Last week I found myself in need of a USB toggle switch. Such a device would allow me to toggle the power on a USB device without having to unplug it. It is true – I suffer from a disorder that requires me to construct a USB switch rather than simply unplug my devices.
This simple device uses a USB extension cord and a slide switch connected to the +5V power line (the red wire). If you happen to have a device [such as an external video card] that requires to be reset every few days, simply toggle the switch when a reset is needed.
Posted in Electronics
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I can see sunspots
I have been on a bit of a quest to observe the sun effortlessly, without discomfort, and with my own eyes. There are plenty of great photos and videos of the sun in different wavelengths, but experiencing the sun without any digitization or intervening detectors has been a goal of mine.
I can finally report the combination of filters that allow anyone to comfortably view the sun.
- Sunglasses
- Quartz Working Welding Shades, shade #8
- 12 ND Gel Sheet 299 (Neutral Density), x2
Posted in Solar
2 Comments
That Caltrain life
I’ve been spending a lot of time on the Caltrain and my impression has been generally positive. If the SF bay area cannot manage to get public transportation working in the peninsula, at least there is a competent private transportation alternative.
Posted in Uncategorized
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Guaranteed Texas Crude Oil
I just completed a purchase of some additional crude oil samples to add to my collection. Here is my new favorite:
Posted in Uncategorized
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Upgrade halogen->LED
We have two 300W halogen flood lamps in the house, but I decided it was time for an LED upgrade. I selected the Cree 18W (90W equivalent) flood lamp as the replacement. I wanted to keep the 6ft tall lamp stand and dimmer, but remove the halogen housing, thermal runaway circuit and reflectors.
Posted in Electronics
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$50 electronics test bench
I’ve been having a hard time finding oscilloscopes and adjustable power supplies in the “hobbyist” price range, but I think I have cobbled together a solution.
A few key components:
- Power supply from old PC
- Make sure to short the correct pins to trick the power supply into turning on. This is usually green to black.
- yellow-black is 12 V
- red-black is 5 V
- orange-black is 3.3 V
- If you want other voltages, well.. time to built a buck-boost circuit!
- Gabotronics Xprotolab mini oscilloscope
- 2MHz sampling
- 8 bits resolution
- $50 (the best part)
Posted in Electronics
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Solar-powered boat!
I recently took a trip to Alcatraz island to see the @Large Ai Weiwei art exhibit. On the way to the island, I was delighted to find that my ferry was solar-powered!
Posted in Solar
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Engine information
One of the perks of having a modern vehicle is that you can use devices to monitor the engine and drive train performance. I was recently using my Vgate Bluetooth Scan Tool OBD2 Scanner to record speed and engine RPM values during a short trip. In the following plot, you can clearly see the six gears of the automatic transmission as straight lines in speed vs RPM.
Posted in Cars, Data
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Pitch to Color
Here is the color wheel used by my electronic instrument, Abella. When the music box is playing “C”, the pitch display appears yellow. Middle “C” is set at 262 Hz, high “C” at 523, and low “C” at 131 Hz, and each is displayed yellow. The remaining notes occupy a RGB-CMY color space.
Posted in Electronics, Music
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Gregory Kimball 