Category Archives: Useful Things

Solis Wi-Fi Hotspot

Last fall we were traveling and spent some time in the Tucson / Lazydays KOA Resort. As part of the amenities, we were given free Wi-Fi access during out stay. The Internet there is managed by Tengo Internet, which we understand loosely means “we have Internet.” Ummm. Maybe. Sometimes. I think it can be interpreted similarly to “Yes, we have no bananas.”

Yes, we had Wi-Fi. We were right across a street from the Wi-Fi antenna, and we had a good Wi-Fi signal. Having a good Wi-Fi signal is not synonymous with having good Internet. Or any Internet at times.

I found that at about 4:00 am I had decent Internet. At 4:00 pm the Internet was so slow it was practically unusable. At 8:00 pm it was so slow that my phone said I had no Internet and it switched to cellular data, at $10/gigabyte. Ouch!!

Tengo Internet had a paid option that they guaranteed would provide 5 megabits/second speeds. I paid. It didn’t help. I still essentially had no Internet connectivity at the busy times of day, and I don’t think I ever saw 5 Mb/s speeds (except maybe at 4:00 am).

After a week of this, when we were depending on having Internet available, I decided it was time to find a solution. I looked into standard mobile hotspot providers, like Verizon and T-Mobile. The problem was that you had to pay a monthly subscription fee whether you were using the hotspot or not. And since we wanted it just when traveling, sometimes for a few days at a time, that didn’t seem like a good solution. And what if the provider I chose didn’t have good coverage in the area I needed it?

Eventually I stumbled across SolisWiFi.co, at that time, SkyRoam. (Some areas of their website still identifies it as SkyRoam.) I purchased a Solis Lite WiFi hotspot, about the size of a hockey puck.

Solis Lite Hotspot
Solis Lite Hotspot

This device has a built-in battery that lasts up to 16 hours. Add an app to your mobile phone to control the hotspot and purchase Internet access, and you’re ready to go. When powered on, the Solis Lite will find the best provider to connect to, and provide you with 4G Internet. It’s not 5G. But good 4G was plenty fast enough for us.

You can connect up to 10 devices to the hotspot. That easily covered both of our mobile phones, an iPad, a laptop PC, and an Echo Dot. Range was easily 20 feet or more.

The Solis Lite worked well when sitting around camp. When we went to the pool, we took it with us. Several times we went to a picnic area in Saguaro National Park, and took the hotspot with us there. We had no cell phone service – none at all. Yet the hotspot was able to find enough signal from some carrier that we were able to access the Internet without problem.

We also carried the Solis Lite in the car when we were traveling. We typically track our trip on maps and other applications on my iPad or our phones, and that map updating can use significant data. Using the Solis Lite hotspot in the car kept us from using our expensive cellular data.

Where does it work? They say in over 130 countries worldwide. USA coverage seems to be pretty good. I don’t recall encountering any place that it didn’t work for us.

How much? The hotspot was about $125. There are several purchase plans for Internet usage. You can purchase by the megabyte, by the day or by the month (with usage caps). If you can predict your usage, the monthly plans are probably the cheapest (your mileage may vary). As I write this, a USA monthly subscription that includes 10GB of data is $40 (there are several other options). That’s $4/GB, much cheaper than my phone data plan of $10/GB (I’ll be shopping around soon…). If you exceed your monthly plan, you can add data at any time. Global plans are a bit more expensive than USA plans.

If you choose to purchase by the Megabyte, that starts at $8 for 1 GB, $35 for 5GB, $60 for 10GB, and $100 for 20GB.

The Global Unlimited Daypass is $9. Unlimited data. Anywhere. Great if you need data just for a day. You can buy these in advance (watch for sales) and activate them when you need.

Check the plans carefully. They seem to change from time to time, so don’t assume that a plan you had six months ago is identical to the plan you can get now.

Where can you get the Solis Lite? Last fall it was available from Amazon. I purchased it directly from SkyRoam, and was very disappointed in the shipping. They don’t seem to care that you might want it soon. It took several days for it to ship, and I think they paid extra to have USPS delay it for a few more days. Right now, Solis WiFi’s site says it’s out of stock. There is one left on Amazon (search for Skyroam Solis). I also found it at Target and Ebay. It’s out of stock at several other places, which makes me wonder if there is a supply problem, or if they may have stopped manufacturing that model and may be coming out with something new.

Was the Solis Wi-Fi Hotspot without problems? No. Several times the hotspot locked up with an error message in the app, and I had to power it off and back on to get it working. When I tried to change the password through the app, I found that the display was white on white – not exactly readable. At one point I had a few GB of data left in the monthly plan, and I was metering it out to avoid buying extra data to make it through the month. The plan expired many hours before the app indicated it would and I lost the remaining data. I suspect a problem in the app having to do with the difference between UTC and local time caused that, but support was unable to tell me what had happened. Overall, though, it worked well.

Note that my analysis and purchase was about six months ago. Things change quickly, so check around for other options. That said, we have been happy with the Solis Lite, and I think we saved some money on our one trip with it. There is a convenience to being able to access multiple carriers. Keep an eye on the app or the Solis website for deals. They frequently have discounts on data (there is a 30% off monthly plans right now). You can always buy data for use in the future.

3D Printed Sundial

A few weeks ago I posted about designing and printing a simple 3D part. This post will be about a more complex object, using a different design tool.

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 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
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.