MARRIED TO A MAKERSPACE GEEK

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I’ve known since I met my Makerspace Geek husband that he could fix ANYTHING. It didn’t always look pretty but it would work. I’m reminded DAILY just how talented he is. Unfortunately, over the years, being somewhat of a minimalist, I ran out of things to put on his Honey-Do List. I would find myself, at times, racking my brain trying to think of something he could fix or make. Because after completing a task and joyfully erasing it from the fix-it/make-it board, he was happy, contented and fulfilled. Lo and Behold he discovered Makerspace. I should celebrate the day as one would a major holiday. It has transformed my little geek into a big geek. He LOVES Makerspace and I love that he has a place to go where he can share, with other like-minded individuals, all the geeky thoughts spinning in his head. He still shares some of that with me but I know that oftentimes my head kind of goes on blank mode and I find myself just looking at him, trying not to nod off and listen. After his joining and I got over his starting every sentence with something about Makerspace, or his approaching total strangers and handing out a Makerspace card, or striking up conversations with family and friends and droning on for, what seemed like hours, about Makerspace, I surrendered. Why??? Because it makes him darn happy, that’s why. And who doesn’t want to see someone they love being happy??

 

So now when we’re eating dinner and I see him chomping at the bit because he wants to be at the club, I wish him well on his merry way and sit back to a quiet evening. If I’m awake when he gets home I get to hear all about the goings-on. I admit to crashing, often before he gets home because when he does he’s often so jazzed that I then have trouble falling to sleep .
Thanks, Makerspace, for making a space for him

3D Printable shock mount for PCM-M10 digital recorder

PCM-M10 Shock Mount

PCM-M10 Shock Mount

Several years ago I played with a lot of audio stuff including making binaural recordings of things like cicadas, train rides, and festivals in Japan, and the singing of tree frogs in my back yard when I lived in a forest in Missouri.  Those recordings were done on a MiniDisc recorder because it was the best available audio quality recorder for people on a budget (i.e. cheapskates) like me.   Time and technology wait for no one, and I’ve been getting the itch to do some recording again, so I recently picked up a Sony PCM-M10 recorder.   This little machine records in many different formats up to and including 24 bit/96 ksps (though self-noise really limits the machine to about 15 actual bits).  The audio is recorded onto micro SD cards so unlike the MiniDisc, you get access to the raw digital data without any compression or associated quality degradation.

My previous recordings were done using a DIY binaural microphone that used a roughly matched pair of electret condenser mic capsules mounted on a wire bail that held the capsules inside my ears.  Even though those mic capsules were pretty noisy, the recordings came out pretty good.  When you listen to them with headphones you get a real “you-are-there”, surround-sound experience that can be quite startling.  You can hear those recordings here: http://mark.rehorst.com/Binaural_Recordings/index.html   Soon, I’ll be starting a new binaural mic project to go with the new recorder, this time using much higher quality mic capsules.

In the meantime I was looking for a shock mount to use when making recordings using the built in mics.  The shock mount prevents low frequency noise from handling, bumping the table the recorder sits on, etc., from being coupled to the mics through the body of the recorder.  I did a web search and found only a couple unsatisfactory designs so I did what any maker would do- I made!

One of the flaws in the few designs I saw was that some of the numerous switches and I/O jacks on the recorder would not be accessible when it was bolted to the shock mount.  They also didn’t look very nice.  After a lot of sketching possible designs on a whiteboard and paring the thing down to a minimal implementation, and spending much too much time making a 3D model of the recorder, I came up with a printable 3-finger design that holds the recorder either on a tabletop or a tripod and keeps ALL the switches and I/Os available.  The only thing you can’t do while the recorder is mounted is swap batteries (but with 40 hours record time on a set of two AAs, that shouldn’t be a problem).

I used DesignSpark Mechanical to make the recorder model and design the shock mount.  DesignSpark makes rounding corners of complex 3D objects easy (nearly impossible in Sketchup), but I did run into some of its limitations that I hadn’t previously considered.  One huge limitation is that there is no way to put any form of text into a drawing without some special work-arounds (use Sketchup to make text, then import into DesignSpark).

CAD drawing of shock mount

CAD drawing of shock mount

PCM-M10 on shock mount- CAD

PCM-M10 on shock mount- CAD

This shock mount design is available here:  http://www.thingi

verse.com/thing:384567

 

I printed the shock mount on MegaMax using Coex3D Aqua ABS filament.

 

CNC Mogul Introduction

A few weeks ago Mike Stone of CNCMogul.com visited the Milwaukee Makerspace.

Mike donated one of his machines to the space for testing and feedback as well as to use for the membership. It should also be mentioned that Mike is local and has his shop and distribution in Wales, Wisconsin.

Joe Rodriguez built one machine and I also put one together at our shop at home. So here are some thoughts on the process as well as some pictures. It isn’t a review as these machines haven’t really been put to the test as of yet. Time will tell.

The CNC Mogul is a general purpose 3 axis CNC kit that is relatively easy to put together and can be used for anything that you like. I’ll be using ours for routing and Joe wants to make a CNC plasma cutter with the one in the space. The basic kit is affordable and it uses the Makerslide as it’s building blocks. The stepper motors are run with a rack and pinion setup on aluminum tracks and gearing as well.

The controller is a Chinese Tb6560 Stepper Motor Driver Controller that is controlled via parallel port.

The power supply is a 24V 14.6 AMP 350W Max Power Supply.

The whole kit can be ordered online from 2ft X 3ft up to 4ft X 8ft. Custom dimensions are also available.

So here is the kit before assembly. This is a 3ft x 3ft kit that I will be building and using with a router.

This is the kit right before opening.

This is the kit right before opening.

Inside the kit there are a bunch of baggies with tons of little parts. You can look at the manual here

I’m assembling the quad rail kit. Once I start pulling things out of the box there is an amazing array of parts that explodes out of it. Fortunately each bag and part are well marked.

Everything that you need to build your own CNC controlled machine.

Everything that you need to build your own CNC controlled machine.

cncmogul03

Everything is labeled really well.

Everything is labeled really well.

Everything is labeled really well.

Everything is labeled really well.

The kit took approximately 3+ hours to put together. The documentation in the manual is hit or miss. The pictures are extremely good and really help in putting this together. The accompanying text is also great for the first 1/3 of the manual and then you’re left to interpret pictures from there. There are a few questions that came up while building this but fortunately I was able to figure it out.

Little by little the parts are being built.

Little by little the parts are being built.

After the gantry gets built and all of the wires are connected it’s time to test. CNC Mogul recommends using Mach 3 for your machine control. And even has a few pointers on how to setup Mach 3 on their site.

I decided to go with LinuxCNC because it’s open source, I’m comfortable with Linux and it’s low cost (free). I loaded it up on a spare computer and after running through the instructions I was able to control the stepper motors on the Mogul.

What I had difficulty with is that the CNC Mogul uses an “A” axis and “Y” axis slaved together. LinuxCNC can do that but you can NOT test for that in the setting up process. You essentially tell the “A” axis to use the same step and direction pulses as the “Y” axis. I also inverted the “A” axis so they would turn the same direction when they are facing each other.

One of the other difficulties I had was figuring out the leadscrew pitch to enter into LinuxCNC. After some experimentation 1.27 inches per revolution seems about right but some more testing is needed.

Once you’re finished building the whole thing you need to mount it to something. I picked up a Craigslist find and the Mogul fit perfectly.

I generated some G-code from Vectric’s Vcarve Pro Zeroed each axis and started to cut.

I still need to put a waste board down and face it off flat and put some type of work hold-down system in place.

After the unit gets setup in the Makerspace the members will have access to the machine and we’ll see how durable it is.

The CNC Mogul with router mounted and ready to cut.

The CNC Mogul with router mounted and ready to cut.

Total time to build, test, and implement the whole system has been approximately 6 hours. There is still some testing and tweaking to be done as well as putting in a dust collection system.

If there are any questions feel free to ask me either on this post or in person. I’ll be putting this through it’s paces as well.

My 2nd test using the CNC Mogul with 2 types of router bits.

My 2nd test using the CNC Mogul with 2 types of router bits.

SnakeBite Extruder Works!

I repaired the Budaschnozzle hot-end over the weekend and bolted the SnakeBite extruder to it and then to MegaMax and tested it last night.  There’s plenty of tuning to do, but the first print looks promising:

 

Start of SnakeBite’s first print

 

More of SnakeBite’s first print

 

Not too pretty but it shows promise.

Not too pretty but it shows promise.

3D Printable Thermal Enclosure For 3D Printer

Well, OK, not the whole enclosure, just the parts that hold it together.

MegaMax can print big stuff but he’s had problems with large prints delaminating.  The answer seems to be enclosing the printer to keep the prints warm while printing.  I designed this box and 3D printable parts to hold it together so that I can take the box apart easily to work on MegaMax or move him to other locations and put it back together when I’m done.  The box is 38″ D x 28″ H x 32″ W.

box door open

 

 

 

 

 

 

 

 

 

 

box door closed

 

 

 

 

 

 

 

 

 

 

 

 

 

The box is made of 1″ PIR foam with corners suitably notched to accommodate the printed parts.  MegaMax has a 450 Watt heater in the printbed so the box gets super-toasty inside.  I suspect it gets a little too toasty but haven’t made any measurements yet.  I’ll soon be moving the electronics out of the box.  I didn’t do anything to seal the seams in the box because it doesn’t seem to be necessary.  I did tape the edges of some of the foam boards with clear packing tape to prevent damage.

Design and stl files are available at http://www.thingiverse.com/thing:269586

Snakebite Extruder Testing

rev7 extruder with hot-end

 

 

 

 

 

 

 

 

 

 

 

 

One of the biggest problems with FDM 3D printing is hot-end jamming.  There seem to be a lot of causes, most of which are not readily identifiable when a jam occurs.  One thing I have found is that after a hot-end jam I can usually grab the filament and manually push it and get it flowing through the hot-end again, though it is too late to save the failed print.  The most common means of driving the filament into the hot-end is to pinch the filament between a gear and a bearing and have a motor drive the gear, either directly (with 1.75mm filament) or via a gear reduction/torque multiplier arrangement (3mm filament).  When the hot end jams, the large force applied by the gear over the small area of the filament that is pinched between the gear and bearing usually chews a divot in the filament thus destroying the grip.

A couple weeks ago I started designing a 3mm filament extruder for 3D printing.  My hope is that this extruder will provide sufficient force on the filament to prevent hot-end jamming from ruining prints.  My design uses two counter-rotating 6-32 nuts twisting on the filament (like the way your hands twist in opposite directions when you give a “snakebite” to your friend) to drive it into the hot-end.  One is a normal, right-hand threaded nut, the other is left-hand threaded.  When the nuts turn in opposite directions, the torque that would try to twist the filament is cancelled while moving the filament forward and reverse without twisting.

The motor has to turn about 1.26 times to move 1mm of filament so there is a huge torque to axial force conversion.   The gear diameter is about 30mm.  That 1.26 rev moves the gear about 119mm at its perimeter.  That means there is about a 119:1 increase (ignoring losses in the gears, bearings, and nuts) in the force at the filament compared to the force at the gear.  That force is applied over a larger area of the filament than the usual pinch arrangement, so it is less likely (I hope!) to carve the filament and lose grip.  I tried stopping the filament by grabbing it with my fingers and holding as tightly as I could but it didn’t even slow down.

The firmware in the printer has to be tweaked so that it knows exactly how many steps of the motor are required to drive 1mm of filament.  The formula is:

32 rev/ 1 inch  X     1 inch /25.4 mm   X    200 steps/1 rev    X  16 microsteps/1 step   =  4031.496 microsteps/mm

For initial tests I just input 4031.5 using the rotary encoder on the LCD interface to the RAMPS board in MegaMax.

Here are the parts that I used:

Left hand threaded tap:  http://www.amazon.com/gp/product/B006YITGY8

5mm brass tubing:  http://www.ebay.com/itm/360828686174

5x16x5mm (625Z) bearings:  http://www.ebay.com/itm/321062568303

Plastic gears:  http://www.sciplus.com/p/PLASTIC-GEAR-SET-WITH-BUSHINGS_40234

I also used a NEMA-17 motor from a QU-BD extruder.

You can DL the STL files for the printed parts here:  http://www.thingiverse.com/thing:261037

Test printing will start in the next day or so and I will post another video showing success or failure.

Fingers crossed!

Laser Cutter Venting System, Version 5.0

Sometimes solving one problem creates a few new ones! As part of the Laser Cutter Room Reconfiguration, the exhaust system got an upgrade. A new, bigger, more powerful fan meant we needed a new way to control it. The previous system (Version 4.0) was a simple on/off switch. That just wasn’t going to cut it for this industrial grade blower. Tom G., Tony W., myself and others spent the holidays installing this new two-horsepower beast above the ceiling in the Craft Lab. Once it was hung from the roof joists with care, Tom got to work ducting it over to the Laser Cutter Room. Finally, when all the heavy lifting had been done and the motor drive had been wired up, all we needed was an enclosure for the switch.

The request went out on the message board. Pete P., Shane T., and I all expressed interest, but life got in the way and it soon became a matter of whomever got to it first would be the one to make it. I ended up devoting the better part of last weekend to this project (much more time than I anticipated) but I can honestly say I’m pretty happy with the result.

LCEC01

The goal was fairly straight-forward: make an enclosure for the switch Tom had already provided. It was a color-coded, 4-button, mechanical switch that had been wired to provide four settings: OFF, LOW, MEDIUM, and HIGH. The more laser cutters in use, the more air you’d need and the higher the setting you should choose. There’s four duct connections available for the three laser cutters we currently have.

There’s a saying: “Better is the enemy of done.” Truer words have never been spoken in a makerspace.

At first I wanted to build the enclosure out of acrylic. Then I remembered this awesome plastic bending technique that Tony W. and some others told me about. I found a video on the Tested website and got inspired. (If you don’t know about Tested, please go check it out. You’ll thank me later.) Unfortunately, my bends kept breaking and melting through, so after a few hours of tinkering I moved on.

Thankfully, we have a small cache of plastic and metal project enclosures on our our Hack Rack. I managed to find a clear plastic, vandal-proof thermostat guard. It looked workable.

I tried laser cutting it, but the moment I saw the plastic yellow and smoke, I knew there was probably some nasty, toxic stuff in it, so I moved to the CNC router. About an hour later I had my holes cut.

Then came the wiring. Up until this point I had been focused on the control box itself. Now I wanted to add a light!

No, two lights! Yeah!

One light to tell you when everything was off, and another that lit whenever the fan was in use. People could look at the lights from outside the room and instantly know if the fan had been left on. (It should be noted that the new fan, despite being twice as powerful than our last, is actually much quieter. Tom added a homemade muffler to the inlet of the blower and shrouded the whole contraption in 3″ fiberglass batt insulation. The best way to know if the fan is running is to open a slide gate damper and hear air being sucked in.)

OK, I totally got this.

Draw myself a ladder diagram and get out the wire connectors… Remember that I need to isolate the signals from each other so any button doesn’t call for 100% fan… A few more relays… Some testing… and done!

Wait a second… the motor drive doesn’t have a ground for the control signal.

Hmm.

Guess I can’t power it from the drive. I’ll just tie into the drive’s ground. Nope, that didn’t work.

I’ll read the motor drive manual. OK, it has a set of “run status” contacts I can monitor.
….and they’re putting out a steady 0.4 volts DC. That’s enough to light up a single LED! …except, no. It’s not lighting. Doesn’t seem to be any real current.

I’ll just use a transistor! That’s the whole point of a transistor!
….well nothing I tried worked.

I’ll build a voltage multiplier circuit!
….and this isn’t working either.

On Day 3 of this “little project” Ron B. made a comment about using a pressure switch of some kind.

Wait.

We have a Hack Rack full of junk and I know there’s this old bunch of gas furnace parts. It couldn’t be that easy…

LCEC02

Yeah. So, three days (and a few frustrating epiphanies) later, this all came together. Press the beige button, get some air. Press the other buttons, get some more air. Any time there’s suction, the red light comes on. The indicator light is powered by its own 24 volt DC wall pack. The pressure switch has both normally open (N.O.) and normally closed (N.C.) contacts so it would be totally feasible to add another light at some point. The controller could display “OFF” or “SAFE” or whatever as well as “ON” or “FAN IN USE” or whatever. The text is just a red piece of paper with words printed on it, then holes laser-cut out to fit. We can trade it out with different words or graphics if we ever feel the need. I was just glad to have it done, so I called it. Better is the enemy of done, indeed.

LCEC03

You can learn more about the evolution of our laser cutter venting system on our wiki!

Further Adventures in CT Scan 3D Ego Printing

 

 

After a long series of manipulations, the CT scan derived  face was successfully used to make a pencil holder (of all things!).  It is about 100mm high and took about 9 hours to print.  You can find files that you can use to make your own mash-ups of my face on thingiverse: http://www.thingiverse.com/thing:203856

3 face cup 2

Successful CT scan processing into 3D printable file

Today was spent researching all the manipulations involved in getting a CT scan into printable form and I managed to get a print out of it.  The process starts with DeVide where the dicom data from the CT scan is processed using a dual threshold, decimation filter, and stl writer.  The stl file contains a lot of unwanted stuff, in this case, soft tissues inside my head that add triangles but won’t be seen in the print, so those are removed by applying ambient occlusion followed by selecting and deleting vertices by “quality” (which will be very low values for vertices on the interior of the object).  This process invariably blows small holes in the desired surface, so you apply a “close holes” filter to fix that (which closed up the nostrils very nicely).  Next you open the stl file in netfabb and rotate and clip unwanted external stuff and apply repairs as necessary.  Finally, drag it into slicer and scale it. slice and print.

First successful ego print!

First successful ego print!