When camping, I frequently would like to know the temperature outside our 2020 T@B 320S Boondock Edge trailer as well as inside. I purchased a “ThermoPro TP60S Digital Hygrometer Indoor Outdoor Thermometer” through Amazon (if you purchase from this link I’ll earn a small commission at no additional cost to you) and mounted the indoor module on the wall next to the Alde control panel using Velcro.
Now, where to locate the outside sensor? I placed it in the propane tank / battery box, just setting it on the bottom. This seemed to work fine. The outside temperature seems to be relatively accurate except when the sun is shining directly on the box. The only problem I could see was that the sensor picked up a lot of dirt, and occasionally some moisture from sitting on the bottom. I was also concerned about dropping something on it and damaging the unit.
I have finally gotten around to moving the sensor to a safer location. I figured I could mount it over the flange at the back of the propane tank / battery box and it would be safely out of the way. When the lid is closed, there is a small gap below the lid where the mount can sit without interfering with the lid closing. Using Fusion 360, I designed a holder for the sensor.
I first measured the width of the flange at the top of the box, and eyeballed how I thought I would like the mount to sit on that flange. I measured the sensor, and made a rough drawing of what I wanted. Then I created a test part in Fustion 360. I just made the end of the sensor mount and about 10mm of the body. That way I could print it in a reasonable amount of time without using too much plastic filament to test the fit. Here’s my first iteration:
I then tested this, and found that it didn’t hang the way I had hoped. It needed something to keep it from tilting.
So, on to iteration #2. I added a little leg to keep it from tilting.
This worked fine. Now that I had tested the hanger, and believed it to be correct, I added the rest of the structure in Fusion 360, and added holes in the bottom to improve air flow to the sensor, resulting in the completed sensor holder.
With recent changes to the FAA rules, it is now possible for drone pilots to fly at night without jumping through as many hoops as before. To be eligible to fly at night, I had to take the update course for my “Part 107” certificate. I also must have an anti-collision light on my drone that is visible for 3 miles in any direction (that sucker is bright!).
When flying at night, one needs to be very aware of their surroundings so as not to hit something that you can’t see. It’s best to check out the location in daylight hours to be sure there are no wires or other such items that you might encounter.
I flew my first night flight a couple weeks ago just to try it out. I flew from my deck, which is surrounded (and partially covered) by trees. I know where they are, and where on my deck I am clear of overhead obstructions. Landing is the tricky part — making sure that I am not descending into the trees or onto my roof. I was successful in flying a short flight and taking a few photos.
Several days later I flew from the Edmonds waterfront. I walked up the beach until I was clear of other beach-goers and had a good place to take off and land (a flat, almost-level, rock). My goal was to get some shots showing the Edmonds Ferry at or near the dock and the city lights of Edmonds. I was successful.
I flew my DJI Mini 2, which is very light-weight and has a 12 megapixel camera. I would like to try again with my DJI Phantom 4 Pro, which is heavier and has a better quality 20 megapixel camera. I think the heavier drone will probably be a bit more stable, which will improve the sharpness of the photos taken with the slow shutter speed required. Although, looking at the photos, the sharpness is quite good considering the camera is “sitting” on a platform floating in the air, subject to wind and motor/propeller vibration. Shutter speeds were between one third and one second with ISO varying from 1600 to 3200. With the small sensor on the DJI Mini 2, these high ISOs made for somewhat grainy photos.
The photo below was shot as a series of nine RAW photos. The drone was positioned at one point in the sky, then three photos were shot using exposure bracketing (each photo with a different exposure) to capture the wide brightness range. Then the drone was rotated, and another three shots were taken. I did this three times. Each set of three photos was merged using Adobe Lightroom Classic to form one HDR photo, resulting in three HDR photos, each with a slightly different view. These resulting three photos were then merged into a single panorama photo, again using Lightroom, to create the final image.
Edmonds Waterfront
Edit 2/13/22: If you want to see the above photo in larger size, look at my Flickr album here.
I’ve wanted to build a custom sundial for my home for years. I have a book (actually, more than one) about designing sundials. The primary one I use is Sundials: Their Theory and Construction by Albert Waugh. This book has lots of information about various types of sundials and includes formulas for designing sundials. I have thought about designing and building a traditional sundial that would be mounted in my front yard, or maybe a vertical sundial on my garage door (which gets sunshine much of the day, but not late afternoon). But that hasn’t happened.
Now that I have a 3D printer, I decided I could make a small sundial (my printer’s print bed is only about 9″ across) using that. I searched for designs, but couldn’t find a sundial I liked in the normal places to find 3D objects to print. I found one that was OK on Thingiverse, but it wasn’t really what I was looking for. Time to design my own!
I wanted to be able to easily modify the sundial for different locations. After all, if I’m going to make a dial for myself, I’m sure I have friends that would like one. And I want to easily customize it to make different sizes.
The sundial I found on Thingiverse had the base and gnomon (that’s the piece that sticks up to cast the sun’s shadow) all in one piece, which made it rather bulky to send in the mail. I wanted something that could be made flat for shipping. So the gnomon needed to be separate from the base, but easily attached.
With all of these requirements, it seemed to me I needed something that I could specify parameters to make it easy to customize, and then based on these parameters do “a lot of math” (not actually so much, but sines and cosines, at least). This is a different way of design than using Fusion 360 or some other similar CAD program, like I did the for the protective feet in a previous blog post. I needed something that could calculate angles and create shapes based on these calculated angles. Is there such a thing? But, of course! There is OpenSCAD, “The Programmers Solid 3D CAD Modeller”. This tool is basically a programming language in which you describe shapes. You write a program, which can include parameters which are used in the calculations. Just what I needed for this project!
The first thing I did was to determine what parameters I would need, i.e., the values I would want to be able to easily change. Obviously, the latitude and longitude of the location where the sundial would be “installed” would have to be easily changeable. What else? How about the size of the base so I could designate whether the sundial would be a 3″ dial, or a 6″ dial, or some other size. Here are the parameters I came up with (as shown in OpenSCAD):
Sundial Parameters
In OpenSCAD, these are dimensionless parameters, but the sizes get interpreted in millimeters by my slicing program. So think of these as sizes in millimeters, except for the locationName, which is text, the latitude and longitude, which are degrees, and the timeZone, which is hours. So the dial described above is 120mm on a side, which is very close to 5 inches.
Here is a photo of the sundial base created by the above parameters:
Sundial Base
Pretty simple, right? A Cuboid (a cube with unequal size sides) for the base, with another cuboid subtracted from it (the depression in the middle), a bunch of cuboids for lines added at various angles, and another cuboid subtracted from it where the gnomon will fit in, then some letters and numbers stuck to the top surface around the edges. Nothing to it! 🙂
And the gnomon is really simple. Just a cuboid the size of the slot it will fit into, and another cuboid to cut away the upper portion at the correct angle (the latitude of it’s location).
Sundial Gnomon
Once you print the base and the gnomon, the gnomon fits into the slot in the base:
Square Sundial Base and Gnomon
With the base and gnomon apart, they can easily be mailed in an envelope. I have sent several to friends in padded envelopes, which can be sent inexpensively, with no problems.
Of course, this all seems simple now. I’ve already done it. Actually creating the sundial took me several days of work to get it just right. A lot of that time was learning OpenSCAD (I’m still just a novice), and also deciding how I wanted my sundial to look. Not to mention getting the formulas right for the basic dial. It took some time to get the hour numbers to print correctly on the dial border. Some of the logic was like, “if the hour line intersects the top border (not the left or right borders), print on the top border (centered vertically), otherwise print on the left or right border (centered horizontally), but don’t print on the bottom border (because the location text is there).” There are still some edge cases where the numbers print in the “wrong” location (which depends on your definition of wrong), but they haven’t occurred often enough yet for me to fix the logic.
For the curious, the code for the Gnomon is:
difference() {
translate([0,-gnomonDepth,0]) cube([gnomonBaseLength, gnomonBaseLength+gnomonDepth, gnomonWidth]); // Full gnomon
//subtract linear portion above gnomon
rotate([0,0,latitude]) translate([0,0,-1]) cube([gnomonBaseLength*4, gnomonBaseLength*4, gnomonWidth+2]);
}
You might recognize some of the parameters to the cube() function as input parameters above, for instance gnomonDepth and gnomonWidth. The other parameters to the cube function (like gnomonBaseLength) are calculated from the input parameters.
If you are curious about the code, or want to print your own Square Sundial, my “Square Sundial” can be found on Thingiverse at https://www.thingiverse.com/thing:4802077.
