Cephalopod Robot Friend, the story so far

Quick lead in:  I am trying to build a cephalopod robot shoulder friend.

I was disappointed that I only learned of Glow Ascii‘s owl robot companion, Archimedes, after Maker Faire Bay Area 2018.  Over the year, leading up to Maker Faire Bay Area 2019, I followed Odd_Jayy‘s spider/bowler Anansi robot companion with similar rapt interest.

Still high off Maker Faire 20191 , I was also excited by the prospect of #CephalopodWeek on NPR’s ScienceFriday.  Between cuttlefish, squid, and various octopuses (especially the “Opisthoteuthis Adorabilis“), there are a LOT of awesome little friends to consider making.

While trying to avoid work, I posted a sketches to Twitter.

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Last week I started designing a few parts, drawing from some experience designing printable prosthetics for the E-nable project a few years ago.  I was trying to build it out of what I had on hand, which did not include elastic cord.  I thought a zip tie might provide enough “spring” and “give” to work.

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I admit, this was a total mess.  I suppose it is only fitting I use this meme featuring Dr. Zoidberg.

Thanks Dr. Z

Thanks Dr. Z

Thanks to some kind encouragement from Odd_Jayy, I kept moving forward.  Rather than focusing on the end of the tentacle, I got to work on the basics of the mechanics – channels for the elastic cord and fishing line, wedges cut into the faces so the tentacle could articulate.

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The tabs on these parts were too thin and tended to break when I assembled them.  However, the next version worked really well.

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These worked a lot better, so I started cranking out parts.

https://www.youtube.com/watch?v=QLUkgY5XDNg

https://www.youtube.com/watch?v=H–MmB1uzrA

The nice thing about these tentacles is that they look somewhat lifelike without actually requiring much in the way of electronics.  As long as I can design a body/housing and put a servo inside, that one servo could possibly pull on 8 different sets of fishing line to articulate all the tentacles at the same time.  And, since it’s just fishing line, there’s no special routing of brake cables necessary.

The tentacles are somewhat larger than I would like, so that means where they connect to the body needs to be similarly large.  There’s definitely room for improving the tentacle segments.  I’ve already designed two different “ends” for the tentacles, so they’re rounded instead of exposed connectors, fishing line, and elastic cord.  Also, to make the curling tentacle look better, I should angle the the top and bottom of each segment.  Another improvement would be to rotate the articulation angle for different segments to give the tentacle a more organic look when moving.

However, if I don’t get working on the body of the robot, it’s not going to ever get done.  Given the size of the tentacles, I’d need to have them all on one side, lest the little robot take over my entire shoulder.  Here are some “Cuttle-Bot” sketches along with a robot body design.  If you look at the design, you’ll notice the connectors are rotated to different angles.  This is so that the tentacles would each spring back together towards each other – and then splay outwards when articulated.

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However, this last design takes FOREVER2 to render in OpenSCAD.  This is at least partially due to design and code inefficiencies, but also due to the number of spherical parts, facets, and “hull” operations needed to make these parts work.

I think I may want to try shrinking the tentacles slightly so I can build a smaller-bodied robot.  Either way, I have to get cracking on at least some kind of housing/body and mounting motors/electronics before I can keep moving forward.

Companion Robots: Building Robot Friends
  1. Cephalopod Robot Friend, the story so far
  2. Cephalopod Robot Friend Progress
  3. CuttleBot Body and OpenSCAD Design Tips
  4. An Assembled CuttleBot Body
  5. Building the Monocle Top Hat Cat for #MicrobitVirtualConcert
  6. Companion Robots and Maker Faire Season!
  1. LONG LIVE MAKER FAIRE! []
  2. Well, a little over 5 minutes []

DIYFaire.com: Hello Maker World!

There were dark rumors going into Maker Faire Bay Area 2019 which imparted a cloud over the event.  On June 8, 2019 I was still reeling from the news Make and Maker Faire were closing, so I bought a domain and created a website (DIYFaire.com, now lapsed) with the idea that come January of 2020 perhaps I might find a way to get together again with far flung friends on the same weekend.

The website is gone, but Archive.org remembers and the WordPress installation may yet exist.  Although I write this preamble on 7/12/2023, the day I will remember I’d heard Maker Faire was coming back, I’d like to preserve that post on 6/8/2019 here on my main blog:

Make: and Maker Faire may be gone. I hope they’re not. I hope Dale and the Make crew figure out a way to rise up. People made things, just for the sake of making them long before Make they’ll continue to do so. Knowing people will continue to make doesn’t really salve my sense of loss. I feel like we’ve lost too much, mourned too much, and it still feels so raw.

 

At the same time I’m not going to miss Makers, because I don’t have to. Makers are not going anywhere. I am going to miss the opportunity to meet up with Makers and far flung friends at least once a year at Maker Faire.

 

Fortunately, the end of Make and Maker Faire are not the end of the friendships sparked and forged there.

 

Here’s my promise to you, right now. On the weekend of May 16-17, 2020 I’m going to travel out to San Mateo. I’m going to stay out there for the weekend. And, I’m going to bring some stuff I’ve made or been working on.

 

I don’t have any idea what “DIYFaire.com” is going to be. If nothing else, it’s a place holder.

 

It’s a “save the date.”

 

If I don’t see you sooner, dear friend, let’s start making something together right now. Let’s make a plan to hang out, share things, and continue our friendship. You’ll forgive me for ending with someone else’s words.

 

“And if you’ve come this far, maybe you’re willing to come a little further. You remember the name of the town, don’t you?”

Maker Faire Application: Vacuum Forming Workshop

DIY Vacuum Formed Arc Reactors

DIY Vacuum Formed Arc Reactors

I’ve been making some notes as I work on my vacuum former and the proposed workshop for this year’s Bay Area Maker Faire.  Here’s some ideas and thoughts, in no particular order.12

  • Workshop Proposal
    • I’ve demonstrated my bucket vacuum former at my daughter’s school a few times – and it is always a huge hit.  The vacuum formed result looks like so much more than the product of very cheap and accessible materials.  Two years ago I put on a presentation at Maker Faire about how to build a vacuum former – and this year I want to try something even more ambitious.  Here’s the slideshow from 2017.

    • I want to do an entire workshop on how to build and operate a vacuum former – and then let people try to vacuum form their own objects.  One of my favorite things to vacuum form is an “Arc Reactor” and then augment it with an RGB flashing LED and a coin cell battery.  However, I think people would also enjoy making goggles and phone cases.  It takes about 30 seconds to heat up the plastic and just seconds to actually vacuum form a shape and let it cool down.

https://www.youtube.com/watch?v=9Prj04gPeLw

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  • New Developments
    • Several months ago, just before Thanksgiving, our stovetop stopped working.  Yeah.  I know.  Talk about timing, right?  While we scrambled to get a new cooktop ordered, delivered, and installed, we also purchased an inexpensive hot plate from Amazon.  I had originally used an old hand-me-down large toaster oven to heat up the plastic, but wondered … is there a better way?  That toaster oven is huge and takes a long time to heat up.  This weekend I was delighted to learn the hot plate heats up very quickly, gets hot enough to soften the plastic, and works as a fantastic and compact replacement for the toaster oven.
      • There are a few caveats to using the hot plate.
        • The heat was more localized, causing the center of the plastic to become thinner and saggier.  When the plastic plates were heated in the toaster oven, they tended to heat more evenly.  Perhaps if I tried a lower heat setting or held the plastic plate higher, this might be mitigated.
        • It’s hard to get a sense of the plastic without actually watching it get soft and wobbly.  This is especially true when the plate is inside the toaster oven – there’s only room enough for one or two people to see what’s going on.  However, with the hot plate, there’s no enclosure3 to obscure an audience view.
        • I was somewhat paranoid about letting the plastic droop down onto the heating element.  I’m pretty sure it would smelled horrible, made a huge mess, been nearly impossible to clean, and made the hot plate unsuitable for any other purposes.  I may try to locate a cheap hot plate from a second hand / thrift store / goodwill to take to Maker Faire.  Though, now I’m also wondering if it might be possible to repurpose an old coffee maker, grill, griddle, or panini press, into the heater for this project.  Maybe if I covered the heating element in aluminum foil first, that would protect the surface?
      • The power switch of the vacuum head / bucket head is conveniently placed right on top for normal operation.  For unusual operations such as this, where the vacuum is upside down, it is decidedly inconvenient.  I used a power strip with a switch which made it much easier to operate the vacuum.  I think I may invest in a dedicated foot switch extension cord for this project.  It’s a very cheap upgrade that would make it a lot easier to do.
    • I also have a prior post discussing some additional ideas on how to improve this process.
  • Accessories / Things to Bring to Maker Faire.  There are SO many little parts to a project – forget any one little thing and you’re going to be making a last minute trip to the hardware store.4 Here’s a few lists of things I will need:
    • Parts
      • Bucket
      • Vacuum head
      • Hot plate
      • Power strip or foot switch extension cord
      • One or two wire coat hangers
      • 6x Small to medium binder clips
      • Wooden dowel (1x 6″ riser, 3x 8″ legs)
      • 3D printed parts (1x plug, 2x riser caps, 3x leg holders, 3x feet)
      • Hot glue
    • Building Tools
      • Drill (for drilling holes)
      • Ruler and / or paper grid
      • Chisels
      • Hacksaw (cutting the wooden dowels)
      • Hot glue gun
      • Sharpie
    • Presentation Tools
      • Heat gun
      • Scissors (cutting plastic plates)
      • Old socks (DIY oven mitts)
    • Materials
      • Examples of plastic plates in various stages of the process
      • Examples of items made, also in various stages of production
    • Consumables
      • Plastic plates
      • Tape (clear packing tape works well)
      • Fishing line
      • Elastic cord
      • Pens (metallic permanent markers)
      • LED’s
      • Batteries
      • Maybe stickers to give away?
Bucket Vacuum Former
  1. How to Make a Vacuum Former
  2. How to Use a Vacuum Former
  3. Vacuum Former – Things to Form
  4. Vacuum Former – Ideas to Improve Vacuum Former
  5. Maker Faire 2017 How to Make a Vacuum Former Presentation Slides
  6. Vacuum Forming an Arc Reactor
  7. Maker Faire Application: Vacuum Forming Workshop
  1. As always, as much to inform you, dear reader, as to order my own thinking and jot things down before I forget them []
  2. DOCUMENT!!! []
  3. And, now that I think of it, it may be the enclosure which causes more even heating… []
  4. Not that this is a bad thing.  But, I’d rather have to go because I want to do go []

PCB Design with KiCAD

It is pretty incredible that you can find a written or1 video tutorial on virtually any topic to learn anything.  Today, I’m particularly thankful to Shawn Hymel, Sparkfun, and Digi-Key for putting together their Intro to KiCAD video series on printed circuit board design.

This series took me from knowing nothing at all about PCB layout and design to ordering my very first board through OSHPark.  My first design isn’t anything amazing – it was basically a breakout board for an ATTiny85 to make it easier to build small projects. 

My first ATTiny hacked tap light was a mess.  I soldered wires directly to the microcontroller making it a real pain to update. ((I ask you – is this the work of a sane man?)) I soon realized my mistake and soldered an 8-pin socket in its place so I could reprogram the chip easily.

This is the alternative to a custom PCB – a rat’s nest of wires soldered to a chip

Mercifully, Shawn’s tutorial series got me up and running very quickly.  This post is not meant to be a tutorial for KiCAD, but more like a “lab notebook” for the workflow to create a board.  If you haven’t built a board yet, go check out Shawn’s series and follow along in KiCAD.  If you are a novice like me, you might find these notes helpful:

Eeschema

  • If you launch Eeschema separately from KiCAD, you can save different versions of a schematic.  Keeping old versions of design files is hugely helpful to me and if you launch KiCAD directly, the option to save different file names and versions is not available!
  • The keyboard shortcuts in Eeschema are great.  With just a few, it’s possible to really get around quickly.
    • “Shift-A” and left click to place parts 
    • “M” to move parts
    • “R” to rotate parts
  • It is necessary to add “PWR_FLAG” to both the power and ground lines.
  • Double check your connections work by clicking on the bug icon. 
  • Assign the parts you intend to use to match up with the symbols using the “Assign PCB footprints” icon.
  • Save your work and “Generate netlist” to have something the Pcbnew will be able to work with.

Pcbnew

  • First configure the Design Rules by going to Setup -> Design Rules.  Shawn pulled these KiCAD Design Rules from the OSHPark.com website.  KiCAD has apparently changed a little since the version used on the OSHPark website, but the settings are easy enough to identify and change.
    • Net Classes Editor
      • Clearance: 0.01.  Track Width: 0.01.  Via Dia: 0.03.  Via Drill: 0.015.  uVia Dia: 0.03.  uVia Drill: 0.015.  Diff Pair Width: default.  Diff Pair Gap: default.
      Global Design Rules
      • Minimum track width: 0.006.  Minimum via diameter: 0.027.  Minimum via drill: 0.013Custom Track Widths: Track 1: 0.03
  • Read netlist” to bring your design over from Eeschema.
  • Placing parts and drawing lines gets a lot easier when you fine tune the Grid.  I started with 5.00 mils at first, then smaller figures to place smaller parts and features.
  • Once the parts are arranged in Pcbnew, connect the ground and power lines using 30 mil traces and everything else using 10 mil traces.
  • Create the outline for the board cutout by clicking on “Edge.Cuts” and drawing with the “Add graphic lines” tool.  Starting with my second board, I began cutting the corners off, so that they were a little nicer to hold and 
  • Label things on the “F.SilkS” and “B.SilkS” layers using the “Add text”‘ button.  Since my boards are so small, I wanted the text to be a fair bit smaller than the default settings.  I edited the text settings by going to Setup -> Text and Drawings.  
    • Copper text thickness:  0.007.  Text height:  0.035.  Text width:  0.035.
  • Create a copper pour with Place -> Zone, then choose “F.Cu”2 and “GND”.3 and draw a box around your board.  Then repeat for the “B.Cu” and “GND.”

Again, I’m a total newbie at circuit design.  If I got something wildly wrong, please let me know.  :)

  1. More frequently these days []
  2. Front copper []
  3. Ground, natch []

Rocklin Mini Maker Faire 2018

15 Second Drawings
15 Second Drawings

My daughter, TinkerGirl, and I are going to be demonstrating our 15 second drawings at the Rocklin Mini Maker Faire this Saturday.  We’re pretty stoked about this since it will be our first time as Makers at this Mini Maker Faire.  We’ll be the ones wandering around with a DIY dry erase board.

If you’re wondering what the heck “15 second drawings” even means… it’s just what it sounds like.  Both of us will each draw whatever you want in 15 seconds.  Whatever you want, no matter how complicated or absurd, drawing before your eyes in just 15 seconds.

Or, we can teach you how to draw anything in 15 seconds.  Or compete against us or perhaps challenge a friend (or enemy?!) to a 15 second drawing.

You want to learn more?!

Regex: Back reference and Self reference in Regular Expressions

This is going to be a very short and niche post.

Sometimes I have to use regular expression or “regex” searches to parse a bunch of text, but I can’t remember how to use the search function to find a particular sequence of character and then reuse those found characters in the text I’m trying to replace it with.  In Notepad++, this would be done as follows:

  • Search string:   (7//*[0-9]*[0-9])\r\n
    • This will find all entries with “7/3” or “7/14” or similar digits with a line return afterwards
  • Replace string:  \1/2018;
    • This will replace those entries with “7/3/2018;” and “7/14/2018;”, respectively

The trick here is that the first set of search information is collected together within a set of parenthesis, which are then referenced back by the “\1”.  If you forget the parenthesis, the “\1” term won’t “know” what it’s supposed to be repeating.

Like I said, very niche.

[SOLVED] Google Pixel stuck in a boot loop after update and full storage

If your Google Pixel is stuck displaying the “G” and forever looping through a boot screen, Google’s support will tell you there is no hope and you’ll either have to do a complete factory reset and data wipe of your phone or send it in so they can do it for you.  However, if you are adventurous or have nothing to lose, there may still be hope.

I’m not saying this will work for you, or that you should even try what worked for me.  But, if you’re as desperate as I was, you would try absolutely anything to get your photos back.1

While out of town on vacation, away from WiFi and cell carrier internet access, I took a lot of photos and a few short videos.  My phone, a lowly Google Pixel with just 32GB2 of storage ran out of space.  It claimed it was at “100%” usage of storage with only a few dozen megabytes of space left.  I leaped into action, right there on the beach, deleting some large documents and ZIP files I had downloaded and then asked the Google Photos app to “Free Up Space.”  Pats on the back!  Job well done!

Except the Pixel had other ideas.  I reached into my pocket later to pull out the phone and take a picture to discover that it was on the white boot screen with the colorful Google “G” logo and a light gray “progress” bar undulating underneath it.  I thought this might be due to the phone overheat and put the phone away.  When I pulled it out later, I found the phone was still showing the same white boot screen.  I don’t know what caused this problem.  I don’t know if it was the Android system update from a few days ago, the storage being mostly full, possibly being too warm from being in my pocket, or what.

I tried everything I could think of and everything I could find to no avail:

  • I was unable to boot the phone into anything resembling active status, not even the last measure of “Safe Mode.”
  • I could boot the phone into “Recovery Mode” which looks like the Google Android robot lying on its back with a front panel open and some text underneath.  However, attempts to “Start”, “Reboot”, and use “Recovery Mode” were all unsuccessful.
  • I tried following the recommendations of the mysterious “Techno Bill” on the Pixel Google Groups to install ADB and Fastboot and then apply a Rescue OTA to the Pixel.
    • If nothing else, this one possibility gave me hope that I could still interact with my phone, somewhat.  I was careful to try out the specific OTA3 for my phone.  As you navigate the various menus in the Recovery screens for Android, you’ll need to take note of the version of Android you’ve got – so you can place the same version over it.
    • As best as I understand this fix, you’re basically overwriting a possibly damaged or corrupted operating system with a shiny new factory fresh version – and that doing so leaves your data intact.
  • The thing that gave me the most hope was this post by Mac_DG on Reddit.  Basically, they said, “If you can get there [the Google recovery screen], and it’s a software problem everything is fixable.”
  • I even spent 43 minutes4 chatting5 with Google’s Pixel support team member, Marlene.  She was sympathetic, but assured me in no uncertain terms that my data was lost forever.  My options were to send my phone to Google or take it to a repair facility for a diagnostic.

Finally, after much searching, I found this thread on Google’s product forum where someone named Jintoku described an identical problem to mine – and someone named Kara Alexander described an identical problem … and a solution suggested by Samuel Cooksey!  If you think you’ve got the same problem – nearly full storage, frozen or looping “G” screen, and unable to enter Safe Mode, it is absolutely worth your time scrolling through this thread to see if this solution may work for you.  It is also worthwhile reading through Jintoku’s conversation with Google’s representatives to see how hard they tried not to do a factory reset on the phone – and just how certain the Google representative was that this was the only possible solution short of outright replacement of the phone.

I will not duplicate the efforts of Techno Bill, Jintoku, Kara Alexander, Samuel Cooksey, and Mac_DG by repeating everything they’ve already said.  Rather, you may use any of the above links from my search to follow along and, hopefully, set you on the correct path.  If you would prefer a condensed guide, with links, I hope this will help:

  1. Follow Techno Bill’s guide on installing ADB and Fastboot.
    1. If you’re on Windows, you either need to follow Techno Bill’s guide on updating your computer’s “Path” or, if you’re a little more comfortable doing so, you can skip steps 1-8 and instead open the command prompt and type
      1. “SET PATH=%PATH%;c:\adb”
      2. The benefit of doing it this way is that you don’t have to permanently add this path to your operating system, it’s a lot faster and easier than Techno Bill’s method, and you don’t have to restart your computer
  2. Download the Developer Beta Preview OTA for your phone6 .
    1. It almost goes without saying that with words like “Developer”, “Beta”, and “Preview” in the title, this version of the Android operating system isn’t for the faint of heart.  If you don’t know what you’re doing or, like me, don’t have anything to lose, you shouldn’t be trying this.
  3. Follow Techno Bill’s guide to “sideload” the Rescue OTA to the Pixel.

If this blog post, that I write as my phone is running the Photos application right now to back up my vacation photos, saves even one person’s data, I will be an incredibly happy person.

  1. After all, what’s the worst damage I could do?  In a worst case scenario, the phone would still be unresponsive or bricked permanently []
  2. !!! []
  3. I believe this refers to an “over the air” operating system update []
  4. I was emailed the chat logs after the session ended []
  5. Since I had no phone, natch []
  6. Pixel, Pixel XL, Pixel 2, Pixel 2 XL []

Loudest 3D Printed Whistle – now with 100% more science

Extremely loud and compact emergency whistle v1

Extremely loud and compact emergency whistle v1

I ordered a decibel meter from Amazon the other day so I could drop some science on the claims from various 3D printed whistles on Thingiverse.  There are several that claim to be the loudest.  Well, today, I began my quest to put these claims to rest.

The closer the decibel meter is to a sound source, the higher it registers.  To eliminate some of these variables, I placed the decibel meter on a counter in front of me and a chair 24 inches in front of that.  For each of the whistles I was testing I stood just behind the chair and gave the whistle three hearty puffs.  The decibel meter, which was set to record and display the “max” reading, would then tell me the loudest reading for that set of three whistle toots.

Without further ado, I declare the “Extremely loud and compact emergency whistle” by Whistleblower on Thingiverse the clear winner at 121.1 decibels.  Both whistles by this designer took the top two scientifically determined spots.

NameThingiverse IDMass (grams)PricePrint Time (minutes)DecibelsSubjective Rank
Extremely loud and compact emergency whistle [v1]29330213.9$0.1222121.11
Extremely loud and compact emergency whistle [v2]29330213.7$0.1118111.53
v29 (Over 118 db!)117916013.9$0.4290110.44
2 chamber whistle (LOUD) [w5]26165128.1$0.2449109.52
Emergency Whistle with Solidworks 2014 source4951721.2$0.047101.85
Whistle Ring Modified [v2]20271151.6$0.05990.86

Just how loud is 121.1 decibels? 1  Well, for starters, it’s just above the pain threshold of 120 decibels.  It’s louder than:

  • Your iPod headphones at maximum volume
  • A baby crying, next to your ear
  • A full symphony orchestra
  • The subway
  • A sporting event
  • A chainsaw
  • A jetski
  • A marching band

It’s on par with:

  • Thunder
  • A shotgun
  • An ambulance siren
  • A rock concert

And, if you didn’t have earplugs, you would exceed the daily safe exposure limit for 121 decibels in 7 seconds.

There may be louder whistle on Thingiverse2 and, if so, please let me know.  I’ll print the model and test against the others in my arsenal.

Default Series Title

  1. This page has several charts to help explain. []
  2. Or some other online 3D design repository []

Loud 3D Printed Whistle Test, Take 2

Impatient for my decibel meter to arrive from Amazon and eager to get more feedback on the loudest 3D printed whistle, I brought the four loudest whistles to work and enlisted the help of two friends.  We performed the test much the same as the last time – only this time they were on one end of a large parking lot and I had driven to the far side to blow each whistle once, then repeated them each once.  Here’s the result on their subjective test:

NameThingiverse IDMass (grams)PricePrint Time (minutes)RankDecibels
Extremely loud and compact emergency whistle [v2]29330213.7$0.11181TBD
Extremely loud and compact emergency whistle [v1]29330213.9$0.12222TBD
2 chamber whistle (LOUD) [w5]26165128.1$0.24493TBD
v29 (Over 118 db!)117916013.9$0.42904TBD

Whether the1 loudest whistle is the v1 or v2 of the “Extremely loud and compact emergency whistle,” Thingiverse user whistleblower clearly designed an amazing, quick printing, low cost whistle.  It has a very high pitched piercing tone that can be downright painful to be near, let alone create. 2

As before there’s a number of different things that could be happening here.  Perhaps the particular tone of this whistle travels better through open spaces (such as a parking lot) rather than through a door and down a hall (such as inside my house).  I know there are some whistles that require a lot of blowing power to hit maximum volume and others which almost “choke” on too much pressure.

In two days my decibel meter will arrive and I’ll try all of these tests again and post a new table.  If you think you’ve got a contender or have seen a really loud whistle on Thingiverse, let me know in the comments so I can print and test it.

Default Series Title

  1. Subjectively []
  2. Again, I had my earplugs in for the test []

Loudest Whistle on Thingiverse… The Answer Might Surprise You!

You'll need a pair of these earplugs

You’ll need a pair of these

Whistles have been a staple on Thingiverse for years, probably because they’re such a small, simple, and impactful way to demonstrate the usefulness of a 3D printer. 1 I don’t know how many there are, but there are a LOT of whistles on Thingiverse.  I’ve been curious about which whistles on Thingiverse are the loudest and conducted a semi-scientific experiment to figure this out.

Six whistles

Six whistles

I say “semi-scientific” because I don’t have a decibel meter.2 My methodology was to have my family at one end of the house while I went to the other side, closed the door, put in my earplugs, and wailed away on six whistles as hard as I could.  In any case, here’s my findings:

NameThingiverse IDMass (grams)PricePrint Time (minutes)RankDecibels
Extremely loud and compact emergency whistle [v1]29330213.9$0.12221TBD
2 chamber whistle (LOUD) [w5]26165128.1$0.24492TBD
Extremely loud and compact emergency whistle [v2]29330213.7$0.11183TBD
v29 (Over 118 db!)117916013.9$0.42904TBD
Emergency Whistle with Solidworks 2014 source4951721.2$0.0475TBD
Whistle Ring Modified [v2]20271151.6$0.0596TBD

I added a few columns that may (or may not) be of interest to you.  I indicated the weight of each whistle, because sometimes I want to know how many whistles I could produce off a single spool of plastic.3  Sometimes I want to produce the loudest whistle for the time I have to produce a whistle.4  I showed the cost per model5 , because it brings me so much joy to know I can make my daughter’s classroom louder than a jet engine for less than the cost of a pack of gum.

I know there are a number of important variables are are simply not addressed in this test.  Different frequencies sound louder or might be easier to hear through the door.  I tried to blow each whistle the same amount, but some whistles are louder with less forceful or more forceful blows.  Once that decibel meter shows up, I’ll be sure to post another update.

Default Series Title

  1. Photo by mosambers []
  2. Yet.  At <$20 on Amazon, you can be sure I’ll be adding actual readings soon []
  3. With careful design, approximately 2,500 whistles per kilogram of plastic []
  4. The v2 of this whistle is the clear winner []
  5. Assuming a spool costs about $30, shipped []