Making, Learning, and Exploring
Touch screens; they just dont have that nostalgic clickety-clack feel of buttons, switches, and knobs. I’m working on a 3D printed tactile toy. The first prototype is looking promising although the white overture filament I am using to print the enclosure is giving me a hard time with bed adhesion.
I would describe the final prototype as a fidget spinner on steroids.
How much does this meeting cost?
Arduino +Autodesk fusion + 3D Printing + Coding = awesome fun!
3D printing an arduino timer enclosure
I completely redid my design for the bounty towel paper model rocket so I could print the model upside down and get much more aggressive looking tail fins for the 3D printed model rockets.
Free Download
I had a few requests for the file so I will post them here. Over time I have found some differences in diameter of the paper towel rolls and you may need to wrap electrical tape around the base to get them to fit properly.
Click below to download a compressed file containing the models in a specific format called .3mf.
After successfully launching a multitude of my 3D printed Bounty Towel rockets, my kids and I decided we needed a more badass rocket launcher than the bland and generic store bought mass manufactured versions. My biggest complaint with the generic store bought models is when you press the switch you get very little feedback on what is happening. This is especially concerning when the rocket doesn’t immediately launch. There is also ample opportunity for improvement in the aesthetics department on these devices.
This project was featured on Hackaday, in their coverage of the Philadelphia Maker Faire.
If we wanted an awesome rocket launcher we were going to have to print, build, wire, and assemble it ourselves!
The whole controller is one series loop: battery → inline 5 A fuse → key switch → arm toggle → momentary fire button → igniter clips, and back to the battery. The continuity LED sits across the fire button: with the key on and the system armed, a tiny (~20 mA) current sneaks through the LED and the igniter to prove the circuit is complete. Press the fire button and the full battery current bypasses the LED and lights the igniter. The voltmeter and power LED sit across the battery so you can see pack health at a glance.
This post contains Amazon affiliate links — as an Amazon Associate I earn from qualifying purchases, at no extra cost to you.
Heads up: the 3D-printed enclosure is a paid download on Cults3D (a few dollars). Any project box from the hardware store works too — the wiring is exactly the same.
Updated August 2026 (rev B): the diagram now shows the inline 5 A mini-blade fuse and marks the three LEDs as 12 V panel-indicator modules. Two things the original diagram left implicit, made explicit: the LEDs in the parts list have built-in resistors — do not substitute bare LEDs (a bare LED in the continuity position would send ~10 A through the igniter the moment you turn the key), and the “1 Ω” element on the right is the igniter itself, not a resistor you buy. The continuity check passes a harmless ~20 mA through the igniter whenever the key is on — far below the no-fire current of standard Estes igniters (if you fly more sensitive e-match style igniters, unplug them until you are ready to arm).
For the second iteration of the bounty towel rocket I made the fins much bigger and I made the nose cone more aerodynamic looking. In an effort to get better flight telemetry we taped two nickels to the inner nose cone in order to get the center of pressure (CP) behind the center of gravity (CG). In our case two nickels was enough for a perfectly straight flight of our 3D printed rocket into the heavens.
For the second iteration of the 3D printed Bounty paper towel rockets I’m now pushing the envelope when it comes to minimum wall thickness of the printed assembly to save weight and material as well as optimizing the print time. I cut down the size of the tapered piece for the nose cone and base that slide into the power towel roll ends. The diameter for the model engine is better but still too much of a tight interference fit for my liking. That will also require some more “dialing in”.
The 3D printed rockets are not satisfactorily stable and have a tendency to flip ass over teacup in midair. After further research I have been most recently enlightened that we need to modify the design parameters such that the center of pressure (CP) is behind the center of gravity (CG) for suitable stability. A destabilizing force is created when the CP is above the CG. the next design is going to have much bigger fins and the nose cone will have internal threads to accept a 1/4 UNC bolt (and nuts if needed) to push the model rocket’s CG forward to obtain better stability.
I always enjoyed building model rockets with my dad and sister as a kid but always found the construction process of cutting, sanding, aligning, and gluing the balsa wood fins to be tedious and take a lot of fun out of the process. Back then the hot glue gun fixed a number of model rocket fabrication shortcomings for me.
For a good while now every time I see an empty paper towel roll I see a model rocket body. I’ve been mulling a concept in my head for some time now to design and 3D print a model rocket nose cone and model rocket fins that could attach seamlessly to a paper towel roll to serve as the model rocket body. We had some empty bounty paper towels in the house so this weekend we fired up the CAD and the 3D printer and gave it a shot. The final results came out better than I could have expected!
It works! Our only problem was that we only had wimpy “A” rated model rocket engines on hand. Due to the weight of the assembly combined with the underpowered rocket engine the first two 3D. Printer paper towel roll prototypes went less than 100 feet into the air. Other than that everything worked splendidly.
My goal for the next iteration is to take the design down to the minimum 3d printer wall thickness (the internet is telling me the minimum is about 1.5 to 0.8 mm for the absolute minimum) and see how well the structural integrity of the design holds up. That combined with some “C” rated model engines should add some serious kick to our rocket power of these 3D printed “bounty towel” rockets. This isn’t rocket science (or is it?)
I’ve been wanting to add multi color printing capability to my 3D printing repertoire and pulled the trigger on ordering a Prusa MMU2S. My son has increasingly become more interested in 3d printing and helped me execute the majority of the build. I was grateful for his help. The whole build took us two long (and I mean L-O-N-G) afternoons to complete the build.
The website says you need to upgrade from the MK3S to the MK3S+ before performing the MMU2S upgrade. I didn’t mind the fact the MK3S to MK3S+ was only $49.99.
To keep this list as dense as possible I am not posting many pictures or photos in the post. Mostly lists of prompts to serve as inspiration.
DALLE 2: Godzilla riding a bicycle, illustration by Michael Sowa
You can request access to the DALL e 2 Online Waitlist <–here.
The Blue Mountain Antique Gas Engine and Tractor Show (also more affectionately known as the “Jacktown Engine Show” is an excellent annual event for anyone interested in antique engine machinery and our industrial history. The event is held in Bangor, Pennsylvania and offers a wide variety of antique engines and tractors on display. There’s something about hit-and-miss engines that just feels nostalgic. Maybe it’s the way they putt-putt along, or the fact that they’re usually found on old farm equipment. Either way, these antique engines are fascinating pieces of history.
There is also a very impressive flea market at the back of the jacktown engine show with a variety of antique and vintage items. Most of the flea market is focused on machinist tools, Americana antiques, and an eclectic assortment of hardware. This year I was casually scanning for another behemoth vise to refurbish but was unable to find one that caught my eye. I picked up a a few hand tools including a very nice machinists file, a demagnetizer, and some deep discounted zip ties for my garage shop.
My children and I enjoyed watching the tractor pull contest.
