3D Printed Astrophotography Computer

control side on telescope

With the recent two month long stretch of clouds and rain, I decided to tackle the number one issue causing me to not take advantage of the rare (lately) clear sky…setup time. Living in the suburbs of Houston with a tiny yard, I don’t have the option of building a permanent, back-yard observatory. My best location is right in the middle of my driveway and even then I only have about 70 degrees of visible sky east to west…but I do have a clear shot of Polaris. The problem was that setting up is an hour long, very physical process and I can’t leave my gear in the driveway all night so I have to tear down at 2-3 in the morning…so…I would talk myself out of it most nights. If I wanted to image more frequently, I needed to simplify my setup/teardown routine!

Step one was easy and the most important. Getting a heavy duty medium size wheeley bar from JMI allowed me to leave the scope setup and just roll it in and out each night. This alone saved 45 minutes of labor!

Telescope

After using this setup for a while, I realized that I was still spending 15 minutes running cables to the computer and power to all the electronics so I started looking at on-telescope computer control systems. I did find two commercial options. The AstroBar was light weight and reasonably priced but feature and performance poor. The Eagle2 had the performance and many of the features I wanted but it was fairly heavy and very expensive. Having electrical experience, a couple of 3D printers, and plenty of cloudy nights, I began experimenting with stick PCs. The results were generally positive but I did run into a few issues. First, I found most of the sticks I tested to be fairly underwhelming from a performance standpoint. Running Windows 10, camera control, image capture, guiding software, etc. on 2 GB of RAM with an Atom processor proved troublesome at times. Plus, there were multiple occasions where I lost my remote desktop session to the stick and I had to drag a monitor, keyboard, and mouse out to the scope to plug in the stick and see what what going on. The first time this happened, I was at the Houston Astronomical Society dark site with no peripherals…3 hour round trip plus setup/tear-down time for no images. Very frustrating! Additionally, at this point, the cable monster was beginning to get a bit out of hand! The telescope looked like it had lost a fight with a drunk Radio Shack sales associate!

It was time to plan my ideal, custom Astrophotography, on-telescope computer/control setup.

Requirements:

  • Incorporate the following products into one system
    • Computer
    • Dew Control
    • Camera Control
    • USB Hub and Power
    • 12v Accessory Power
  • Provide at least 6 USB 3.0 ports (primary camera data, guide camera, PoleMaster, mount control, hand controller if doing PEC, focuser, one extra)
  • Power status monitor
  • Small integrated touch screen display (back up to lost remote sessions)
  • Single cable running off scope (power)
  • Small
  • LIGHT WEIGHT

After two months of prototyping and testing I am very pleased with the finial product…I call it The Cube 🙂

Specs:

  • Weight – 982g/2.16 lbs (this is actually 74g less on-scope than my previous non-integrated setup)
  • Size – 16cm/6.25 inch cube
  •  Intel M5 CPU, 4GB of RAM, 256GB of storage
  • 4 channel variable dew control w/low voltage cutoff
  • 7 external USB 3.0 ports each delivering up to 2.4 amps
  • 3 internal powered USB 3.0 ports
  • 5 inch multi-touch LCD display
  • Real-time voltage/amperage monitor
  • Highly regulated power control for the compute stick
  • QHY 10 camera control (TEC cooling/power/status)
  • Switched control for USB Hub, PC, Dew Control, and QHY CCD Camera
  • 4 unswitched 12v 5.5×2.1 mm accessory power jacks

Design and construction

I began the process by taking all the separate components I was trying to integrate and attaching them to a wooden block that could mount on the telescope so I could prove the concept and get a feel for the wiring involved and any potential pitfalls.

Prototype

Next, I 3D printed some components that would let me mock up the internal spacing requirements. The USB hub I decided to use based on size and weight was wedge shaped. I had to measure the angle and print a test wedge (orange component below) to stand the hub vertical for the mockup. The yellow stand below straddles the power distribution block and the buck converter used to supply the correct voltage (5v) to the USB hub. The red box houses the compute stick power regulator (more on that below) and the green shelf mocks up the location of the compute stick complete with opening for the cooling fan.

The next step was to layout the front and rear panels. The front panel contains the USB hub, individual power switches (hub, PC, dew control, and QHY10 camera), PC power regulator control, master power meter, and dew heater outputs. The rear panel contains the touch screen and dew heater controls.

As a starting point I found a great parametric box and panel maker script that allowed me to use OpenSCAD to define my panel layouts mathematically after careful measurements with an accurate set of digital calipers.

Screen Shot 2017-12-26 at 11.06.25 AM

This method let me rapidly print and test prototypes for fit and layout.

Time for the real design work. Using the prototype prints from OpenSCAD as a starting point, I used SketchUp Pro 2018 to design the final box and panels. The front and rear panels feature raised lettering which allowed me to change filament colors once that layer was reached during printing (I went with light grey panels, orange lettering, and a black box to match my Celestron RASA/CGX-L setup). The upper box has an inset detail with precise holes for the QHY DC-201 status LEDs (more on that below). The lower box has a built-in wedge to lock in the USB hub in the correct position as well as built in tabs for positioning and holding the power distribution block and buck converter. Additionally, the compute stick shelf and integrated latch has a dovetail which joins it to the lower box half.

Printing time!

Final parts ready for assembly.

One of the trickiest aspects of the build was powering the Intel STK2MV64CC Compute Stick. When I tested earlier Atom based compute sticks, all I had to do was wire up a mini USB plug to a 5V power supply and the stick fired right up. However, I wanted a stick with a full m5 CPU and 4Gb of RAM which meant going with the USB-C powered version. The first thing I did measure the input voltage and current with a USB-C multimeter.

Compute Stick Power 20

Thinking I was in good shape with 5V, I tried a simple 12V to 5V USB-C converter.

Compute Stick Power 12

The stick would power-up, enter the BIOS check screen, then shut down…odd.

So I tried a higher end buck converter…same result…power-up, BIOS check, shut down.

Compute Stick Power 14

So, I decided to take apart the AC power adapter that came with the stick to see how it worked. This unique adaptor plugs into the wall and then delivers 5V over USB-C. Additionally, the wall adapter itself has two additional USB 3.0 ports that act as a hub over the type C connection. (the stick only has one 3.0 port on-board).

Compute Stick Power 2

Inside, I found a normal 110V AC to 5V DC convertor attached to a daughter board containing the USB 3.0 ports and USB-C connection.

Measuring the output signal on the USB-C link, I found a non-standard signal embedded in the normal data channel. It seems that Intel decided to stop users from using any power supply except the supplied Intel version. If the BIOS does not detect this input signal on the data channel of the USB-C connection, it shuts down. There is no way around it. I guess they were tired of users burning up their compute sticks with crappy cell phone chargers or other poorly controlled power supplies. My options at this point were to run a LONG USB-C cable along with the 12V power cable down from the scope to the ground and use the Intel power supply…or…get creative!

I realized that the daughter board was the only component that mattered and it was very small and light weight. The bulk of the power supply was the 110V to 5v converter which I didn’t need. I already had an extremely accurate voltage regulator in the Cube which I was planning on using to supply 5V directly to the USB-C port on the compute stick. Now I simply needed to supply that same 5V to the daughter board and use it to supply the connection the compute stick. So, I desoldered the daughter board from the rest of the power supply, tested the voltage (it was outputting 5.14v – 5.22v to the daughter board), soldered on some new leads, and printed a very small box to house the card internally. At a cost of only 32g, I was able to power the stick internally and I gained two additional powered USB 3.0 ports inside the box which proved very helpful later in the design process.

The next bit of major circuit reworking dealt with the dew controller. I decided to use the excellent 4-channel dew heater control unit from Thousand Oaks Optical . But, obviously, I didn’t want the plastic housing or much else from the retail unit. I just wanted the control board.

To save weight and allow the board to sit as close as possible to the screen on the rear panel, I desoldered and removed the 4 output RCA jacks and the 12v lead and aux 12v RCA input. I also removed the primary choke and soldered it back on the rear of the board to lower the profile.

Next, I soldered new RCA output leads and 12v input leads directly to the back of the board and provided strain relief with hot glue.

One final bit of major electrical work before assembly. The QHY DC-201 has 5 status LEDs that provide information on voltage, TEC cooling, and camera fan.

QHY 8

I wanted to mount the DC-201 inside the Cube but I didn’t want to lose visibility to these status LEDs. So, I unscrewed the housing and removed the board. Using a straight edge, I carefully cut off the portion of the box with the status codes printed on it (I’ll use it later during assembly). Next, I VERY CAREFULLY desoldered the 5 LEDs being sure to label their position and polarity (LEDs are single direction electrical components). Using a very fine gauge solid strand wire, I re-soldered the LEDs to the board with 4″ long “extensions” protected in heat-shrink tubing.

Time to gather all the parts and clear the work bench for assembly!!!

First, front panel assembly.

Rear panel is next. The slots to the left and right of the screen allow me to attach a red overlay for imaging at a dark site with light policies.

The lower assembly begins by attaching the power distribution block and buck converter for the USB hub into their pre-printed spots on the lower box half.

Next, the USB hub is slipped into its custom fit wedge which features a lip to lock it in place. No glue or screws required.

Dropping the front panel in completes the front of the box.

Time to begin wiring all the switches, converter, regulator, and meter.

Wiring 4

Adding in the dew controller power (later put on an internal 2.1mm plug so the rear panel could be easily removed for servicing the Cube). Also wiring in the 12v supply for the switch’s LEDs.

Wiring 5

The Cube features 4 unswitched 12v aux jacks. These are a simple barrel connector soldered to leads and protected with heat-shrink tubing. I choose this particular connector because it came with a rubber cap to protect unused ports.

Adding in the aux jacks, the compute stick power supply, and internal USB 3.0 ports. Note the white USB-C cable to power the compute stick and the 3″ USB 3.0 cable connecting the hub to one of the internal USB 3.0 ports on the red power supply. The other 3.0 port is used for the touch screen (more below).

Wiring 6

The compute stick is attached to its custom printed shelf with a simple compression latch. The shelf is designed to place the stick in the center of the cube for maximum ventilation.

The compute stick is attached to the screen via HDMI (for video) and USB 3.0 to mini for power and touch. While the USB cord is moderately flexible, most HDMI cables are not. Additionally, the connections are on the side of the screen with only a few millimeters of clearance. Luckily, there is a company that makes flat ribbon cable in various lengths between 5mm and 80mm with every type of termination you can imagine. You simply order the tips and ribbon and snap them together. I used a 20mm straight USB 3.0 to right angle USB mini and a 10mm straight female HDMI to right angle HDMI.

Dew controller connected and the lower half is complete!

Wiring 9

The top half of the box contains the QHY DC-201 and the Losmandy dovetail adaptor.

First, the modified QHY DC-201 is attached to the roof of the top half of the box and the LEDs are inserted into their custom printed holes. The previously removed portion of the DC-201 is glued into an inset on the outside of the top of the box.

Next a custom 3D printed adaptor is attached to the top of the box to mate with a FarPoint dovetail clamp.

The QHY DC-201 is connected to the lower half power distribution with a 2.1mm plug and the two halves are screwed together.

bench cam side

Now, the only wire running off the telescope is a single 12v line. This can run from a battery or a well regulated power supply…I’m a big fan of BK Precision and use their model 1688B for my setup.

So far, this has really increased my imaging time. I can roll out of the garage, PoleMaster polar align, and be imaging in about 10 minutes. I can put the scope away in about 5 minutes. And I can run the whole setup from the comfort of my house with a remote desktop session to the compute stick.

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Is GMail letting more spam through?

Is it just me or did the GMail filters slip a notch.  I’ve gotten 14 spam emails in my inbox in the last 2 days which is 14 more than I received in the previous 2 years.  Don’t get me wrong, they are still far better than any other provider I’ve ever used but I hope this isn’t the start of a trend…

Best CSS Reference

Sitepoint has always been a decent online community and publishing company for web developers. They have articles written by top designers and coders and a number of really great reference books available for purchase. Recently, however, they added a new free reference section to their site that is incredibly useful. Currently only a CSS Reference is available but they are working on an HTML and Javascript section as well. There are many CSS references out there but this is by far the easiest to use. It is not written as a tutorial but rather a simple lookup and explanation (with samples) of every CSS property, rule, workaround, filter and hack. I few clicks and I found modifiers to properties that I had no idea existed.

Sitepoint CSS Reference

Blogging made easy with Word 2007

I really love blogging but one of the biggest headaches is dealing with the online text editors. I’ve found that the editor built into WordPress is one of the best out there but even it is a bit quirky. Spell Check works in Firefox but not Internet Explorer. Keyboard shortcuts for formatting are hit and miss. Adding a picture is a major hassle…First you have to compress the image, and then you have to upload the picture and add it to the text of the blog. Resizing the image and laying it out in line with the text is next to impossible without switching to the raw code and editing the HTML by hand. I love coding web sites but when I want to blog I just want to blog. I want a true what you see is what you get (WYSIWYG) editor.

Enter Microsoft Word 2007. Imagine using all the document creation tools you’re familiar with in Word as the editor for your blog. Word 2007 can directly upload to most blog servers. I don’t mean typing in Word and then cutting and pasting into a new blog post on your server. I mean typing in Word, formatting in Word, adding pictures in Word and then clicking Publish in Word and having it show up on your server. Word 2007 can upload directly to the following blogs; Windows Live Spaces, Blogger (blogspot), SharePoint blog, Community Server, TypePad, WordPress, and most others if you have an API for your blog. You can even define an alternate location for images if you don’t want them hosted on the same server as your blog.

To begin, open Word 2007 and click on the new “Office Button” located in the top left corner of Word and choose publish>blog and bang out a post. Insert any images and format everything the way you want it (there are lots of online tutorials for using Word). You could type your post and then click publish>blog but switching to blog mode first will eliminate the page breaks and margins. It will also limit your image and page formatting to things that can be recreated in HTML.

The first time you enter blogging mode you will be prompted for your account information. If you have more than one blog don’t worry, Word can handle this.

Simply select your blog provider and click next

Enter the URL for your blog in the space provided (mine is eventhorizons.wordpress.com), enter your username and password, check “Remember Password” if you want to be able to publish without entering this information next time. Click “Picture Options” if you want to define another web server to host you images on.

As soon as you switch to blog mode you can access to the blog toolbar.

This has some great features.

Publish

Clicking this button will post your entry to your blog and upload all your images. You can choose to Publish or Publish as Draft. I always select draft so that I can check it one last time online before I make it public.


Home Page

This simply opens your default browser to your blogs home page

Insert Category

Clicking this button adds a category dropdown to your post. You can select from any of the categories that you’ve previously defined on your server or enter a new one. Click it again to add a second or third category to the posting.

Open Existing

This is really cool. Clicking here will give you a list of all of your posts. Even post that you did not create with Word show up. Using this tool you can open previous post in Word and edit them.

Manage Accounts

This menu lets you edit your account settings or setup additional blogs to manage. If multiple blogs are configured you can select one to be the default.

When you create a post there is a dropdown to select your account (if it is different from the default).

You can also title your post

Double clicking a picture pulls up the picture toolbar which has a number of great features including cropping, borders, edge effects (soft edges, glow, drop shadows, bevels, reflections, and 3-D rotations), brightness, contrast and compression. Compression is one of the most useful…By default Word will upload compressed JPEGS of all your images…no more need to edit your pictures before blogging and no more 3MB pictures on your blog!

Picture with shadow and reflection

Picture with 3-D rotation, soft edges, and bevel.

There are about 40 presents as well as full control over all the options for an almost infinite amount of combinations.

Hope this saves you some time on future blog posts (course now you need to buy Office 2007!)

 

Make your own 360 degree panoramic picture

I often get asked for advice on setting up a home shop so I started writing a series of posts on selecting tools and arranging your work space when I realized I wanted to include one of those cool interactive 360º scrollable & zoomable panoramic pictures you often see on web sites advertising vacation spots. These images offer users a virtual tour of the environment and just look really cool. I begin the process of learning how to create these images with one goal in mind. It had to be free! I wasn’t going to buy some panoramic lens for my camera, I wasn’t going to pay some company to produce it, and I wasn’t going to shell out any money for software. After 2 weeks of research and failed experiments I finally put all the pieces together. Below you can see the results of the experiment and a step by step how-to guide if you would like to make your own virtual tour (for free).

Click here to take a virtual tour of my shop
(4 Mb file)

launch.jpg

To begin, you simply need a camera and a tripod. Take a series of pictures (15-20) rotating the camera a few degrees each time. When finished, you should have a set of pictures covering the entire 360º view. Try to make sure your pictures have some overlap as this helps the software when it stitches together the final panorama. I also found it usefull to put the camera in manual mode. In auto mode the camera adjusts the picture based on lighting. As the lighting may change for different angles, your pictures may not all look the same. This will make your final panorama have obvious seams. Manual mode fixes that. Here are the images I took of the shop. As you can see, each picture shows a slightly different area of the shop (and you can see the jatoba table waiting to be completed on the floor…).

thumbnails.jpg

Now you need to download the software that will create the single panoramic image from your photos. The best free tool I found was AutoStitch. After downloading and launching AutoStitch you can play with a few settings (although I used most of the defaults). I did change the scale value (edit>options) to 50% to increase the detail of the final product.

auto1.jpg

Now click file>open and select all the images from earlier. As soon as you click OK, AutoStitch will begin to create your panoramic image and save it as pano.jpg in the same directory as the original files. Be sure to move or rename the file if you want to try again as AutoStitch will overwrite without warning. Mine looked like this when it was complete.

panoramasmall.jpg

The next tool you need is some software to take your panoramic image and turn it into an interactive movie. I found that the free version of Pano2QVTR worked great. It can even add clickable hotspots to your movie but I choose not to use that feature. After installing and launching Pano2QVTR you’ll need to change one setting. The default setting for image type is equirectangular but you need to choose cylindrical.

2q1.jpg

Next you need to tell it where to find your panoramic image (pano.jpg) from AutoStitch. Click the … button next to the “Cylindrical image” field and locate your panoramic image file

2q2.jpg

Under the “QuickTime Output filename” you can choose the location for your completed movie. Under the settings tab you can also change the size and quality of the final movie. When you are ready click “Create” and Pano2QVTR will take care of the rest. It’s surprisingly fast (about 30 seconds) and upon completion it will show you a preview of your movie. After that you can email or post it to the web if you choose. If you are posting to a web site, here is the minimum code for embeding a quicktime movie.

<object CLASSID=”clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B” width=”600″ height=”420″>
<param name=”src” value=”garage.mov”>
<param name=”controller” value=”true”>
</object>

 

There are other options you can choose to include such as an auto download of the QuickTime plugin. A excellent explanation for all the embedding options can be found here.

Have fun making your own panoramic movies!

PS the shop setup posts are coming soon…

 

Create Virtual CD-Rom Drives

Warning – Boring technology content ahead…

This one was pretty interesting. My sister-in-law works at a preschool that has a small computer lab (8-10 computers) and 10 or so educational games that the kids play. Here’s the issue…

  1. The games are all on CD-Roms
  2. Every game requires the CD to be in the drive to play.
  3. The kids are not allowed (nor are they old enough) to switch discs.
  4. The school owns one copy of each game per computer for a total of close to 100 discs.
  5. The kids may play 3-4 different games during their time in the lab.
  6. One teacher (my sister-in-law) has to switch out the discs each time they switch games.
  7. Copying the files to the hard drive (even installing the game that way) does not fix the problem…they still get an error telling them to “Insert CD to continue”.

The solution is to create virtual CD-Rom drives and mount (copy) an image of each game disc to it’s own virtual drive. There are a number of products to help you do this but one of the easiest (and free) versions is MagicDisc (download here). This software allows for the creation and management of up to 15 virtual drives. To get started you first need to uninstall any games that you wish to run this way. If it was originally installed from the real CD-Rom drive it will continue to look for that. After creating a virtual drive you will reinstall from there. This technique can be used for any CD or DVD (assuming you have a DVD drive) not just games…you could keep “Weekend at Bernie’s” loaded up all the time without carrying the DVD around. That’s probably a bad example cause who doesn’t keep “Weekend at Bernie’s” around all the time. Once everything is uninstalled you need to download the software from the link above (they have both 32 and 64 bit versions) and install the software. Once installed you will see the MagicDisc icon in the system tray.

1-system-tray.jpg

Right click on the icon to access the MagicDisc menu. By default one virtual drive will have been created. If you need more click on “Set Number of Drives” and choose the number you need – up to 15.

2-increase-drive-number.jpg

As soon as you select the new number your computer will detect and install new hardware…one for each virtual drive.

3-new-hardware-found.jpg

In fact if you look under “My Computer” you will see all of the additional drives…the computer in this picture only has one physical optical drive.

4-virtual-drives.jpg

Next we need to create our image files…think of these as copies of the discs although you won’t see each individual file. Do this by right clicking on the system tray icon and choosing “Make CD/DVD Image”

5-make-image-menu.jpg

You’ll be prompted for the source of the image (make sure you have the disc in the CD-Rom drive at this point). You’ll need to choose a location on your hard drive (or network) where you want to store the image (I made a directory on the root of c:\ called Games and stored all the images in there. You will also need to name the image file…pick something that makes sense like the actual name of the game or movie…

6-save-as.jpg

After you’ve created the image remove the disc from the drive. Now we are ready to mount the image. This is the term for loading an image onto one of your virtual cd drives. Right click on the system tray icon and choose
“Virtual CD/DVD-ROM>Pick a drive letter>Mount”

7-mount-menu.jpg

You will now be asked to choose an image file to mount…navigate to where you stored the image you created earlier and select it.

8-select-uif.jpg

After you select the image you will see a verifying image progress bar and when that completes it will autorun the disc (if the disc supports that). At this point you can install the game or watch the movie or any other functions just as you would with the actual disc in the computer…in fact it will show up under “My Computer” just as it would if it were a physical disc.

11-my-computer-mounted.jpg

This will persist if the computer is rebooted or even if MagicDisc is closed. To remove an image select the drive from the system tray icon and choose “Unmount” or you can select “Unmount All Drives”. You can alway remove virtual drives by changing the drive number.

Hope this helps someone else out there!