A few pictures from recent stargazing sessions.
Stargazing
Author Archives: bryanpryor
Three Zone Amplifier for Outdoor Speakers
This project was really fun and I love the finished experience. I set up 3 sets of outdoor speakers for my Deck/Patio area. Music comes from an Amazon Echo Dot that synchronizes with the rest of the Dots throughout my house.
I tried a single set of speakers but couldn’t get the coverage I wanted without having to crank the volume way up at the source.
Solar Eclipse Finder Scope
My original design Solar Eclipse Finder Scope. I sell these on eBay and Etsy
I’m planning to view the April 8, 2024 Solar Eclipse in totality and plan to bring a couple telescopes with me. One telescope will be set up with a filter to view the sun through the eyepiece, and another will be projecting the solar image a few feet away to create an image of the sun that’s about 16″ diameter so that all of us can monitor the progress of the eclipse before totality.
It quickly became clear that aligning a scope to the sun, without looking at the sun, was harder than expected. I tried the shadow method and got it to work eventually, but I wanted a much faster and easier way to do it. I searched around for a solar filter for my finder scope, or a special solar finder scope and found some commercial products in the $50+ range, but I didn’t really want to spend that much, especially since I was outfitting (at least) 2 scopes. This sounds like a job for 3D printing!
I took a look at my favorite finder, a Tel-Rad, and decided I wanted my 3D printed finder scope to be just as easy to use as that. I went through a couple of iterations, but finally came up with a nice finder scope that is super fast to use, lightweight, and looks really nice, too!
If you’re interested in purchasing one, I sell these on eBay and Etsy
I decided to print these in tough, durable PETG so that it would be more temperature resistant than the standard PLA. I printed a super thin, translucent screen on the bullseye finder so the sun lights through it. You can see the bullseye pattern from both sides, as well as the illuminated area.
The finder scope mounts to a dovetail, and is adjustable side to side and up/down. I designed it so it ships flat and assembles easily with 4 stainless steel machine screws. Based on requests, I print this in both black and white bodies. This is one of my favorite designs for a 3D printed part yet!
The Best Value Router Bits for Hobbyist CNCs
I’m working to find the most economical router bits to use for my small CNC router that runs a Makita 1/4″ router as the spindle. “Best” in my opinion won’t necessarily be the absolute best bits to run in a production business. This will be skewed more towards lower cost bits, or the “best value” bits. Many hobbyists like myself have a hard time spending tons of money on nice router bits for the occasional 1-2 jobs per month that we run.
Also, machines like mine are usually feed speed limited. In my case I can only run 100 inches/minute, so I can’t ever take full advantage of the chipload on bits over 1/8″. Sure, I can turn my spindle speed down on my router some, but this tends to heat up the motor if I try to run it at the slower speeds. I prefer to run the RPM faster and reduce the feed forces, knowing that I will be sacrificing tool life.
Right now I have a few bits I’m gravitating towards using, and each has a place.
- 1/4″ Freud 2 Flute – My favorite “general” bit
- 1/4″ CMT 2 Flute – Very similar to the Freud, but sometimes cheaper
- HQ Master 1/8″ 2 Flute – I’m trying these out to see if they can become my new ‘general use’ bit. The price is right at about $2/bit, but these are 1/8″ bits instead of the 1/4″. More details on that later.
- Binstak 1″ 2 flute carbide insert bit – This is going to become my general purpose surfacing bit. I’m really liking it. If I had a 1/2″ router on my CNC spindle I’d consider something larger in diameter for surfacing, but this 1″ seems to be fine for my needs. I love the cheap carbide inserts, and right now I have used this both in the CNC and in a router sled to flatten slabs. It’s a great cutter so far.
- Amana Tool RC-45711 – 1 flute 90 degree carving bit. Pretty good, but not perfectly balanced. Nice general purpose workhorse for engraving, and this allows 4 fresh cutting edges per insert. Very economical.
- Amana Tool RC-1024 3/4″ Insert – Not the greatest. It’s at the bottom of my list for a reason. Unbalanced, so you can only run it at slower speeds. It is nice and economical, but I worry that it will damage my router bearings more quickly than it should. Not nearly as nice as the Binstak.
Case for OnStep Controller with Hujer Shield
Here’s a look at the case I designed and 3D printed for my OnStep Controller. The primary electronics are an ESP32-based board such as the Wemos D1 R32. This is paired with Roman Hujer’s OnStep Shield and some TMC2130 SPI steppers.
Box was made to accomodate a 50mm 12v fan I had available, but could easily be sized to fit a 40mm fan if desired. Honeycomb vents on the top of the box.
Fully parametric Fusion 360 file can be found here, as well as STL files for the top and bottom. Don’t mind my messy fusion model, I’m no expert, but I’m sharing the parametric model so you can modify as you want.
Roman Hujer OnStep Shield
I decided to try the OnStep Shield designed by Roman Hujer since I didn’t have much initial luck with the CNCV3. I found George Cushing’s website that sold assembled Hujer Shields as well as Smart Hand Controllers, and the pricing was very good. I ended up purchasing an assembled ESP32duino/Hujer PCB, as well as the Smart Hand Controller (SHC).
This was a MUCH easier way to go. All I had to do was plug in my TMC2130 drivers, connect the wires to the motors, and it was working! Well, it was almost that easy. George had already flashed the software onto this and it was configured for my basic setup, although I still need to adjust the steps for each axis based on my final gear ratio I use.
Connecting the motors was completed using an ethernet cable. The 2 ethernet cable jacks on the Hujer shield are used. I found an old cable, cut it in half, then wired the adjacent pairs together. WhiteOrange +Orange, WhiteGreen + Blue, WhiteBlue + Green, WhiteBrown + Brown. The 8 wires in the ethernet cable become the 4 wires to the stepper motor. The first 2 sets go to one motor coil, the second 2 wires go to the second motor coil.
Choosing Electronics for Onstep with a 12″ Dobsonian
I’m documenting my complete process of learning while I try to convert a 12″ Zhumell Z12 Dobsonian to GoTo using Onstep. The Onstep Wiki and Message Board contain a wealth of information, but much of it is written by people who are MUCH more comfortable with electronics than I am. They are so good at what they do, they forgot the simple questions that a total newbie will have. I am going to document my build in as much detail as possible to hopefully empower other newbies like myself to take the plunge.
After reading the Wiki, I decided the easiest starting point for myself was to go with the WeMos R32 with CNC V3 Shield. I’m going to keep my first build as simple as possible while I learn. I may choose to upgrade features in the future. This initial documentation will focus on getting a WeMos R32 up and running with a CNC V3 Shield, and appropriate stepper motors and drivers.
UPDATE: This ended up being harder than expected with the TMC2130 drivers. Take the advice from the OnStep Wiki and just use a fixed microstep driver like the LV8729. After having issues with the CNCV3 Shield and TMC2130 drivers, I opted to try out the OnStep Shield by Roman Hujer. I found this at https://www.stmbluepillkits.com, but you don’t have to buy from there. George Cushing assembles full kits, which is the closest thing to a complete kit I have found. I’m going to document my experience with the OnStep Shield in another post to keep this one as clear as possible.
Here’s the TLDR version of my components used, with approximate prices (2022). There are many places to buy these such as Amazon, eBay, Ali Express… Amazon isn’t always the cheapest, but it had available parts when I was ready to order, which is rare in 2022.
CNC Shield V3 – $11
UNO R3 D1 R32 ESP32 – $11
TMC2130 V3.0 Drivers, 4 pack (only need 2) – $33
Random Wiring I ordered to help assemble – $7
Jumpers / Headers – for setting microstep mode and SPI – $9
First things first: I didn’t know what a WeMos R32 was. It’s an Arduino Compatible board, but not made by Arduino. The WeMos R32 uses the ESP32 processor, and takes all of the programming that an Arduino does. This WeMos R32 board is the ‘brains’ of the setup. It holds software and sends commands to the motor drivers.
The motors I chose are a set of 400 step Nema 17, 0.9 Amp stepper motors. 
I chose the TMC2130 SPI drivers. I chose these because they were available on Amazon, while many other driver options were not available in the U.S., at least not for many months. They can handle up to 1.2A RMS, so they should be fine to use with 0.9A motors. Drivers take the signals for step and direction from the WeMos, take additional power from a power supply, and amplify that to send it to the motor coils.
The final electrical piece used is an Arduino Shield Called the CNC V3 Shield. What is an Arduino “Shield” in general? My simplistic answer is: A shield is any board that plugs on top of the standard Arduino. Think of it as template wiring that makes it easier to connect other electronics to the Arduino so you don’t have to run as many wires and solder your own components together. The CNC V3 Shield makes it easy to plug in stepper motor drivers to the Arduino. It’s not technically needed, but it looks to be a real time saver, and for around $10 it’s worth it.
Converting a 12″ Dobsonian to OnStep
I have been bitten by the astronomy bug and quickly learned to love two things: aperture and GoTo telescopes. My first experience with a computerized GoTo scope came from a Celestron NexStar 6SE, which is a very nice scope and will open up a TON of viewing for many people. The GoTo feature is wonderful for those of us that have less than ideal viewing conditions such as light pollution.
I also had a chance to look through a friend’s 12″ Dobsonian telescope, a Zhumell Z12, and was amazed by how much brighter the views were. I quickly found myself wanting one of these wonderful scopes as well, but couldn’t find myself paying for a full goto 12″ or 14″ scope like the Skywatcher 300. As of February 2022 when I started this journey, a scope like this would cost around $2500 with full computer control. If you choose to go the Cassegrain approach, a new Celestron CPC1100 will cost ~$4000 at today’s pricing.
I ended up purchasing a 12″ Zhumell Z12 of my own, and decided to convert it to a computer controlled GoTo Scope myself. Given that a new Zhumell Z12 goes for ~$1300, that leaves about $1200 to break-even on a control system. I’m estimating I can get similar features in a $400 budget, which should be a nice savings. Especially considering that I’ll probably copy that system over to my friend’s Z12 as well.
I decided to use the OnStep software to control it because it looks like there is a robust user community supporting this, and it will give me the long-term ability to upgrade/repair any electronic failures without being held hostage by a shortage of parts from Orion or Celestron.
I’m going to have this as a primary post to document the process of the build, and hopefully link to the steps along the way. I’ll start with a list of my questions, and answer each one in a post to give more documentation.
How to select the motors/drivers to use for this?
Learning to Program the Controller
How to mechanically adapt to the telescope? Many files will be uploaded to: https://bryanpryor.com/telescope/
AZ motor Mount and Wheel
How much will this cost?
Custom Telescope Case
I have picked up more hobbies over time, and one of my newly rekindled hobbies is stargazing / astronomy. I picked up a used 114mm Newtonian reflector telescope and needed a sturdy travel case for it, and quickly. While there are some commercial options available, none would make it to me in time for my travels, so I decided to build one myself.
I decided to make the box large enough to hold the scope optical tube assembly (OTA) with the focuser and finder scope still installed. This made the case slightly larger dimensions, but does allow for more foam around it.
The basic idea is a box that allows about 2″ of foam on each end of the box. The foam is cut to match the diameter of the tube and suspend it mid-box. Most of this box was made from scrap wood I had already, so it’s 1/4″ plywood for the top/bottom/sides and 3/4″ plywood for the ends. Joints are glued and brad-nailed together. The 1/4″ plywood is to keep the weight down.
With the 1/4″ being a little flimsy, I decided to stiffen it by adding some 3/4″ strips of pine inside. This will help stiffen/straighten the box without adding a ton of weight. it also gives plenty of surface area for glue to attach the bottom panel.
A quick test fit shows the OTA will fit nicely in the box!
I decided to add a little protection by adding some 1/4″ thick strips of oak to the edges. These are cut to length and glued/nailed in place.
The top is a piece of plywood that is edged with Oak. The oak is rabbeted to allow the plywood to be recessed. The corners are mitered for a clean look.
A few stainless hinges, some cheap rope to keep the lid from opening too far, and the custom CNC cut foam pieces complete the package. The gap around the tube is just large enough to slide in my box of eyepieces in the bottom, housed in an old cigar box!
Here’s a quick look at the foam pieces I cut to suspend the tube.
Curved Socket Organizers
This is a project that took 2 years to come to fruition. I always get into an organization kick at the start of each year, and it looks like I started thinking about this in January 2019. Apparently organizing my socket drawers didn’t take top priority, so this idea has just been sitting on the sidelines ever since. Here’s a peak at the finished product:
I wanted a socket organizer that didn’t waste a lot of space, nested well in my drawers, was portable, and most importantly was marked with high visibility numbers. I think I’ve hit most of my targets. My last step is to come up with my preferred color combination to identify metric and SAE tools. Red/Blue, Red/Gray, Red/Black…. I’m not sure on that one yet.
It took me a long time to finally come up with the curved shape I settled on. I usually think in straight lines, not curves, so this was harder for me than it should have been. A lot of the time spent on this project was time learning Fusion 360 and Inkscape. I use both programs, and am learning the benefits of each. For the laser, Inkscape is the program I use and it took a bit of time to try to make a scaled ‘CAD’ style 2D layout.
I picked up a CNC “K40” laser cutter at the start of the Coronavirus lockdowns and have had some fun learning to use it. I decided this would be a perfect way to use up some scrap wood and make a useful project at the same time, so I decided to try this on the laser instead of the CNC router. You can see my cardboard ‘fixture’ that I use to locate the wood and my preferred work holding solution: masking tape. I don’t want parts blowing around from the air assist.
Here’s some of the first parts out of the laser. I’m doing a test fit. As you can see, I’m having some issues with getting a clean cut all the way through this plywood. I did 2 passes at 5mm/s, 70% power. Additional. passes didn’t seem to help.
Here’s the metric and SAE tray cutouts I made, along with the old socket tray I was using to hold these sockets.
I ended up making 3 pieces: A top piece with numbers engraved, a middle piece with the same holes but no numbers, and a bottom piece with no holes.
The 3 layers were then glued together with wood glue. This was a bit messy. Super Glue / Cyanoacrylate glue might be a better choice here. I may try that in the future.
Here’s the parts after glue-up and with a bit of sanding to remove most of the char from the laser. This is the one thing I don’t like about the laser, but I think it’s a necessary evil.
And finally, some action shots in the the toolbox!
