10/18/2023 Map Stopped Working?
Visit this post for the fix
Mark and Bill,
First, let me start by thanking you for your wonderful software project! I'm loving the continued innovation, ease of use and stability improvements.
My project is on the bigger side, measuring 98" wide by 38" tall and utilizing 411 pixels. I spent a stupid amount of time on this, but I wanted a piece of functional map art to hang in my office and be a conversation piece for years to come. It is also a project that combined many of my interests, including aviation, electronics, Photoshop and woodworking.
First, some photos of the finished project:
I stole and adapted ideas from a lot of different places. Mark, I saw your lite brite and fiber posts later, but was already working on a similar idea. I wanted the LEDs to be smaller than the 12mm pixels. I opted for 1/8" acrylic rods to act as light pipes. This provides a pretty clean look and provides some flexibility on the pixel mounting and density. This was very time consuming. I cut them all to size, then polished each end with 150 then 400 grit sandpaper. Imperfections are easy to see, so I spent a lot of time with my hand cramping in front of the TV. I have lots of tools and none of them produced a good result, so I did it all by hand.
For the map, I did a descent amount of work in Photoshop to get it laid out the way I wanted. I leveraged the US Planning map along with 9 pieces of sectional, which themselves in many cases were multiple sectionals stitched together to get the coverage I wanted. I then overlaid the ARTCC airspace map and center names. Then modified the print legend with the livesectional legend, framed it up, etc. Everything is upscaled to 600dpi, so the Photoshop files are about 8GB.
For the print, I worked with a local graphics / sign shop to direct print it on 1/2" MDO board. I had them use their CNC machine to drill the holes, although for many reasons, I probably won't do that again. I'd just drill them myself if I ever do it again (I don't plan to). Cost of this was just under $500.
I was working hard to make it as low profile as possible with about 1" of working depth on the back. I discovered late in the game that the upgrades for livesectional are delivered via a re-flash process. That, along with other reasons, the plan was changed to allow access to the Pi without puling the map off the wall. I didn't want to redo the entire frame, so I added a slide out 'door' on the bottom to access the PI. I had to mount the Pi at an angle to get it to fit in less than 1". I also added a power switch, so I could power off the project. The power consumption is descent, so the power switch drives a relay that does the heavy lifting.
I used Foreflight to pick the airports with weather, lay them out, and plan the cable routing. I converted inches to miles and laid out the cable routing to minimize the wasted pixels / splices.
Power is handled by a 180W 20V Lenovo laptop charger, run through a 24V relay, then through a pair of 5V regulators. Power is injected on the string in 5 places. I had gotten a few power supplies off Amazon and they were all garbage. I don't have an oscilloscope so I don't know exactly what was wrong, but the lights were very unreliable until I finally switched to the laptop supply.
Ambient light sensor with a 1/4" light pipe.
The Pi on the sliding rail, connected via a ribbon cable for ease of removal. The legend is pretty dense, so I had to stack the pixels and provide shielding between them. I used terminal strips everywhere, which provides a nice secure connection and the ability to change my mind, which happened about 10x on this layout.
Lastly, instead of using a level shifter chip, I decided to use a sacrificial pixel 0 running off the 3.3v Pi power to do the job. It's easy and has worked flawless.
Anyway, I hope this helps someone with their project. It was a fun build and I'm loving it so far.
Thanks again!
Vance
Vance, Wow!
Beautiful work. What an ambitious project. This is a great summary of your build. I made it a sticky post so it will stay at the top and make it easier for others to find it.
A couple of questions if you don't mind;
- With that large of MDF, how much does the project weigh?
- How long did it take to finish the project?
- The 1/8" rods, where did you source the raw material?
- The LED's lay on top of the back end of the rod, correct? How is the rod secured in the hole?
- The use of Foreflight to layout the run of lights is inspired, can you expand on how you set it up--changing miles to inches?
- You used 2 Tobsun boxes, and it looks like they take the 12v from the laptop power supply and reduces it down to 5v, correct? Where did you source these? That's a great idea for larger projects.
- The sliding rail to access the PI is great too. In my development, getting to the back continuously is a pain. Can you explain the design a little further?
- Finally, can you explain the sacrificial LED as a level shifter? I'm sure this could be a nice trick others would like to use.
Thanks again for giving us such a great rundown, this will help a lot of others in their build. - Mark
Hi Mark, thank you very much, I appreciate the kind words. I've been wanting to do this for awhile, but one positive side effect of COVID is that it limited my travel, so I was able to get back in the shop and build stuff.
Happy to share. I'll do my best to answer your questions here:
- With that large of MDF, how much does the project weigh?
- So, to clarify, this is MDO. It is plywood with a thin MDF like overlay and it is painted. It is very common to sign or graphics shops. I didn't weigh it, but really not that heavy. Maybe 40-50 lbs total for the finished project. Nowhere near as heavy as MDF would be and it has the advantage of having something for screws to hold onto.
- How long did it take to finish the project?
- I didn't document, but I'd estimate I have around 150 hours into it. But that includes a bunch of time researching and testing/trialing every aspect. It took a couple weeks from when I turned over the image files to the graphics company to get the finished product back, largely due to them drilling the holes.
- The 1/8" rods, where did you source the raw material?
- The LED's lay on top of the back end of the rod, correct? How is the rod secured in the hole?
- Yes, exactly. The rods are generally held pretty well by friction. I transported it face down and had a few that had worked their way forward maybe 1/16", so just pushed them back flush once mounted. In a few spots, I had to put a barrier between pixels to stop light bleed. I just used a very thin, annealed aluminum.
- The use of Foreflight to layout the run of lights is inspired, can you expand on how you set it up--changing miles to inches?
- This will vary for everyone based on the scale of their map. The max reach between two pixels is about 5", which is about 225NM on my map. But, if you do that, the adjacent pixels have to be really close. Generally, I tried to keep the 'distances' below 125NM. Also, you'll see some zig zag back and forth, which works good based on how the pixels lay out.
- You used 2 Tobsun boxes, and it looks like they take the 12v from the laptop power supply and reduces it down to 5v, correct? Where did you source these? That's a great idea for larger projects.
- https://www.amazon.com/gp/product/B07V7YY5X6
- This is 12-24v regulator. The Lenovo supply is 20V and those regulators output a solid 5.05V.
- I used two as they are only 75w each and I was definitely over that.
- The sliding rail to access the PI is great too. In my development, getting to the back continuously is a pain. Can you explain the design a little further?
- This was interesting. The basic design is like a wood drawer slide design. My options were limited with only 1" of height to work with. If I had 1.5 or 2", I would have built a little drawer with a bottom to mount to, but I digress.
- I had to sand and shape a bit to get everything to work and fit, so opted to leave the mounted side of the rails split. This allowed me to adjust them independently, but mostly this was done due to space limitations.
- In hindsight, I wish I had fully stained and finished it. I spent so much time on the details and then left that kind of half done. The reason is because I had already applied paste wax to the rails while working through fitment issues and I didn't want to start over or try to get it to take stain after that. They are out of sight most of the time, but still.
- The rails are mounted to the 'drawer front' via standard pocket holes.
- Lastly, and I think this was kind of clever, I found a push release latch with a magnetic tip. So, to operate it, I give it a little push up, which unlatches the mechanism and the latch pushes out the drawer. The magnetic bit keeps it in place while retracted, considering it is on the bottom side and gravity would tend to let it work its way out over time.
- https://www.amazon.com/gp/product/B07V9LR53T
- Finally, can you explain the sacrificial LED as a level shifter? I'm sure this could be a nice trick others would like to use.
- Here's where I got the idea: https://hackaday.com/2017/01/20/cheating-at-5v-ws2812-control-to-use-a-3-3v-data-line/
- This is interesting. I went back and re-read the article. I'll admit that I'm not 100% sure why it is working (an oscilloscope would be really handy right now).
- The basic premise is that the 3.3v logic coming off the Pi is too low for the pixel running at 5.05v to detect the logic high, consistently. Instead of doing the trick with the diode to drop the 5v supply to 4.3v, I just tried it running the pixel off the 3.3v supply from the Pi and it has worked 100%.
- Only thing I can figure is that the ~3.3v logic coming off GPIO18 must be regulated down a bit vs the 3.3v coming off the supply. So, when it goes through the pixel, the logic signal gets a slight voltage bump that allows pixel #1 to reliably detect the highs, even though it is running at 5v and the logic signal is still 3.3v.
- In any case, adding a diode and running it 4.3v would certainly still be an alternative option.
Cheers!
Vance
Vance - I'm looking at your pictures, and it looks like you've mounted the light sensor inside the picture frame somehow. What did you use to suspend it, or fasten it in?
Apologies for my late response, hadn't logged in for awhile. The light sensor is mounted on just a generic stand-off and then I used a piece of 1/4" acrylic to act as a light pipe to get it through the frame, similar to how I did the LEDs with the 1/8". I stuck the end of the photo sensor into the hole with a nice glob of hot glue to help secure everything. It works great in my office. Cheers!
