Kill A Watt Power Meter

20160125-110540.jpgI use this Kill A Watt meter to measure any device I have electricity questions about.  I also use it to measure total system power usage and even to track cost over time.

For the price, a Kill A Watt meter eliminates so many questions and has even given me some answers I didn’t know the questions to yet!

Highly worth the cost!

Online Triangle Calculator

triangle_calculator
Triangle Calculator from ostermiller.org

This is a triangle calculator.

Specifically, this is the open source triangle-calculator provided here:

https://ostermiller.org/calc/triangle.html

Since an LED emits light roughly in the shape of a cone, we can use triangle math to predict the amount of area an LED in a particular installation will light up.

After the calculator has any three parts (not only the ones I entered) of the triangle, it will calculate the rest of the parts.

In the calculator pictured, I’ve entered the three values that are depicted in green – the calculator figured out the rest.

For this example, I know:

  • I have 90° lenses
  • I have to cover a 20″+ diameter of surface area

I need to know how high to mount the fixture to get 20″ in diameter of coverage.

Here’s how I filled out the calculator:

  1. Divide the 90º lens by two to get angle 1: 90° / 2 = 45°
  2. The light is perpendicular to the water, so angle 2 is 90°
  3. Divide the diameter by two for the radius you need to cover, for side 120″ / 2 = 10

From this, the calculator tells us (side 2) that the light should be mounted 10″ above the water.

Here’s a simple diagram I created based on some similar calculations:

72x24_1
Light diagram by Matt Carroll. aka TheRealMattCarroll.

Spectrometer

 

This is my Project STAR spectrometer.  It was very inexpensive.

img_3218
The Project STAR spectrometer. Clockwise from the top-left, the long, curved feature is the housing for the graduated scale; next to it is the small light-intake port; at the bottom-edge is the whitish diffraction grating which is just above, or in front of, the eyepiece.

I  use it for examining the color of different lights inside and outside.  (Don’t look directly at the sun through this device – or anything else!)

It works by taking in light via the small opening at the upper-right.

The light bounces off the diffraction grating at the bottom of the photo.

It then spreads out over the graduated scale, which is inside the curved feature at the top of the photo.

I view the scale through the eyepiece that’s at the bottom of the photo.

I don’t get a histogram showing relative wavelength intensity, but it’s really easy to see what wavelengths are strong or weak, or which ones are missing.

I love having this!

 

 

 

 

spectrometer_output
View through the eyepiece of a Project STAR spectrometer. The light is from a 48″ Phillips 6,500K T12 lamp.
spectrometer_light_intakes
The Project STAR spectrometer. Clockwise from the top-left, the long, curved feature is the housing for the graduated scale; next to it is the small light-intake port; at the bottom-edge is the whitish diffraction grating which is just above, or in front of, the eyepiece.
spectrometer_intake_port
The Project STAR spectrometer. Clockwise from the top-left, the long, curved feature is the housing for the graduated scale; next to it is the small light-intake port; at the bottom-edge is the whitish diffraction grating which is just above, or in front of, the eyepiece.
spectrometer_backlight_port
The Project STAR spectrometer. Clockwise from the top-left, the long, curved feature is the housing for the graduated scale; next to it is the small light-intake port; at the bottom-edge is the whitish diffraction grating which is just above, or in front of, the eyepiece.
spectrometer_refguide
The Project STAR spectrometer. Clockwise from the top-left, the long, curved feature is the housing for the graduated scale; next to it is the small light-intake port; at the bottom-edge is the whitish diffraction grating which is just above, or in front of, the eyepiece.