A phone with a frickin’ laser!

My recent acquisition of a Meade ETX-90 telescope with computer go-to system for locating objects in the sky got me thinking that it would be nice to have a system to locate objects in the sky when you’re looking through binoculars or a telescope that doesn’t have a computer and motors to drive it.  To that end I came up with the idea of mounting a green laser pointer, commonly used by astronomy nutz to point out objects in the sky to noobs, on a cell phone or tablet running a program such as Google SkyMap or Skeye.

sky laser all parts

CAD rendering of the parts

After much thought and a few prototypes I came up with a system that allows a laser to mount on a phone and that assembly to mount on a tripod, a handle, or a telescope.  The tube that holds the laser has adjustment screws to allow the laser to be aligned with the SkyMap on the phone.  It also has to slots that fit over standard gun sight rails.  On one side I have a phone/tablet bracket that has a gunsight rail and slides into the laser tube, and the other side can be used for a rail that mounts on a tripod or a handle.  Extra rails can be mounted on telescope tubes.  I haven’t yet designed a binocular mount, but will soon.



Parts printing on MegaMax

I printed the parts on MegaMax with Octave fluorescent red filament (that’s why the colors vary in the photos- the flash apparently excites the fluorescence in the picture with the handle).   All the parts fit VERY tightly together but I included screw holes for extra security.  The phone/tablet mounts on the bracket using velcro tape.  I think it may be better to print or buy a cheap case to fit the phone than screw it to the phone/tablet bracket.  I’ll be posting the design files to Thingiverse shortly.


Phone and laser mounted on handle


Phone and laser on a tripod



Laser Cut Cocktail Recipe Coasters!

Years back, I used to throw a lot of cocktail parties.  Between myself and two good friends, we owned five cocktail shakers and 35+ martini glasses.  During the parties, we’d typically be the only three people shaking martinis for all the guests.  Though that’s awesome, it also means we missed out on much of the socializing and mingling during each party.
blog21In preparation for a recent birthday party, the solution came to me: Use Lasers!  So, I laser cut ten coaster-sized pieces of basswood and then laser engraved my twelve favorite Martini and Champagne cocktail recipes on them.  I also cut stands for them that had a laser engraved “best practices” guide for shaking Martinis – you know, the things that bartenders are typically too busy to do for you: Chill your glass before pouring your drink into it, shaking your drink until it is sufficiently cold, etc.  The drinks have recipes that taste better than what most bartenders will make for you, because they include things like an amount of lemon or lime that they’re too busy to squeeze into your drink.
blog22The party was an even more awesome experience for me, because I wasn’t only shaking drinks all night.   It was also even more awesome for the guests, as they found that great cocktails are super easy to make!  And who doesn’t like to make things? blog26 Also, the carbonated Gin & No tonic is real crowd pleaser!  See my previous post about home carbonation for more info, and note that all types of inappropriate things can be carbonated:  Gin, Ardbeg Corryvreckan, grapes, etc!

How To Laser Cut Really Big Halftone Photos

Wanting to up the ante a bit after having the Makerspace laser cutter chop out hundreds of city blocks to form a big map of MKE, I decided to laser cut a  24” by 18” halftone image!  As it required the laser cutter to carve 10368 circles out of an off-yellow piece of 98 Lb paper, the cutting took 1.3 hours and produced quite a bit of confetti.  I’ll display this with a purple (rather than black) paper behind the off-yellow laser cut paper.  In person there is an interesting transition from an abstract purple/yellow shape into a black and white image as one moves further away from the image.  You may even want to sit back from your monitor to improve the “image quality.”


Check out this video of the laser cutter in the middle of cutting 10000 circles!  Note the mysterious logic employed by the laser cutter to determine the order of its cuts.

I imported a photo into GIMP, and desaturated it to produce a black and white image.  After bumping up the contrast and darkening it slightly to nearly saturate the darkest areas (and avoid any totally white areas), I brought it into Inkscape.  Inkscape can create halftones in a two step, manual process.  The first step is to draw an 8 pixel by 8 pixel circle in the upper left corner of the 1133×720 pixel image, and select Edit->Clone-> Create Tiled Clones.  To create a rectangular grid of halftone dots whose sizes are set by the color of the image below, use these settings:


From a quick test cut of a particularly dark area, I found that I needed to add an offset between each row and each column to account for the kerf of the laser.  I.e. the laser beam has a cutting width that is wider than that of the line, and so in the darkest areas of the photo the halftone dots overlapped, causing a large section of the paper to fully detach. That led me to make this test strip with 11 shades of grayscale, evenly spaced between pure black and white.  I laser cut this test strip with various offset distances between the rows and columns in order to arrive at the optimal 10% extra offset between adjacent rows and columns shown in the above settings. Note also that the smallest size circles may not even be exported from Inkscape due to their infinitesimal dimensions (i.e. if you export as a .pdf).  The minimum gap between circles with 42% speed and 100% power on an 1133 pixel wide image blown up to 24″ is 0.79 pixels, which is 0.017″.

test_tripApplying these same settings to the image created a 128 by 81 array of circles, for a grand total of 10368 vector objects.  In my first trial run last weekend, I found that sending this much data to our 60 Watt Universal Laser takes 5 minutes and results in a print error I noticed only after hitting start!  After 1.3 hours of vector cutting, I found that a few of the rows and columns were shifted a bit from their intended location.  It’s not clear whether this had to do with the print error, or if the paper moved slightly during the cutting process.

In order to improve the second version (shown at top), I chose to move away from the rectangular grid of halftone dots – recall that Kays and London teach that hexagonal close packing is for champions.  The reason to abandon the rectangular spacing is to improve the dynamic range (i.e. to make the blacks blacker).  For example, rectangular grids of circles pack at an “efficiency” of Pi/4, which is 79%, whereas hexagonal close packing results in a pi/6*sqrt(3) packing, or 91%.  That means that the darkest sections of the image will be darker, as more of the light colored “front” piece of paper can be cut away.  See the image below, and note that the hexagonal pattern does indeed appear darker.


It turns out that Inkscape doesn’t easily permit this.  I ended up spending an hour or two fiddling with the column and row offset settings using my 11 black/white tone test strip to find settings that gave the hexagonal offset with the closest, even hexagonal spacing between adjacent circles.  The following settings worked great for an 8 by 8 dot on the darkest square of the test strip:

hex_arrayI test cut this yesterday, sending ¼ of the data at a time to the laser to avoid printing errors. However, part way through the cutting, cut-out paper circles stuck to the long air assist nozzle of the laser head (ironically) hit a washer I was using to weigh down the paper to prevent movement while cutting. The paper shifted by about 1mm, which was enough to make some adjacent halftone dots overlap and cause others to have a visibly wider spacing.

In the process of cutting that photo, Shane happened by and mentioned that vector cutting 10368 objects may be just as fast as the typically-very-slow raster cutting time.  With three clicks, I turned off the vector outline of the halftone dots, and selected a fill color.  After test cutting a row, I found that he was right.  Check out the difference between raster  (100% speed, 100% power) and vector (42% speed, 100% power) in the darkest section of the image – the area with the closest spaced circles:


The vector halftone dots are perfectly circular, though the edges are a bit rough.  Some of them have a very small border and so are a bit fragile.  The raster halftone dots are not very circular, but the edges are very smooth and the boarders are slightly wider.  I chose to raster cut the 24″ x 18″ image, and found that the raster cutting time of 1.4 hours was nearly equal to the 1.3 hour vector cutting time.

Note that many programs can create halftones, though often the results will not be suitable for laser cutter use:


The next step is to laser cut this image into wood.  Also, Inkscape will let you draw any shape to create tiled clones from – so please do share photos of any halftone images you create with star shapes!

Giant Laser Cut Map of Milwaukee

I’ve been on a laser cutting kick lately.  In the last two weeks, I made 9 travel coasters, two of which feature neighborhood maps of places I’ve lived.  Though I could have just raster cut these very small coasters, generating the vector version allowed me to create this big map of Milwaukee, Wisconsin!  This wall hanging map is the maximum size of our largest laser cutter: 24″ by 18″!  Boom!


This map was inspired by a project made by my friend NJStacie a while back.  While she has both the infinite patience and the limitless awesome that allowed her to use an X-acto knife to cut out all the city blocks of Boston from an actual map, I used a laser cutter and software. To create images for my roadtrip coasters, I simply took screen captures of google maps, and processed them into vector files using GIMP and Inkscape.  There are so many extraneous details in google maps (lines for buildings, the text labeling street names, etc), that it was clear I needed an alternate approach for making this map.

Its easy to get a small google map without text labels, check out the url of this page.  My first approach to get more than 512×512 pixels was to use the Google Maps API, which is a toolset to imbed an interactive google map into webpages using Java.  The great thing about it is that the rendering style is completely configurable. Even better, there is a GUI to quickly configure your desired style, and automatically generate the JSON object to pass to the style property of the MapOptions on your webpage.  Instead of investing 10 or 15 minutes reading about how to integrate all these steps, I just created the style, and took a few .png screen captures.  I opened them as layers in GIMP and combined them to create the following grey and black image:


I saved it as a .png, and imported it into Inkscape, selecting Embed Upon Import. I created vector data from this raster image by first selecting Path -> Trace Bitmap, opening a dialog box with many choices.  I really only experimented with the top two import choices, Edge Detect and Brightness Cutoff.  I found that Edge Detect gives two outlines, one of the streets and one of the city blocks.  For this reason, Edge Detect seems to be the best choice to create the widest streets, and therefore the strongest paper cutout.  It required some cleanup though, so I selected Path -> Break Apart, adjusted the Fill and Stroke, and then just deleted all the street outlines (thereby widening the spaces between buildings, which is effectively the streets).  As some of the streets were to narrow to really form one continuous outline, they formed a lot of smaller street segments that I deleted in five or ten minutes of fast and furious clicking.  After all those steps, a vector version of the following image was produced:


I did a few test cuts to find a power/speed that cut all the way though some colorful, 98lb, 25″ by 19″ acid-free archival paper I picked up.  The goal is to use enough power to cut though, without using too much power, which widens the kerf (laser cut width), thereby undesirably narrowing the streets.  This ended up being 100% power, with 52% speed. Check out the laser cutter in this real-time (not sped up) video.  Note that one typical problem of having both air assist and super-power fume-removal suction while cutting is that the laser cut bits tend to flip over into the cutting path, potentially resulting in an incomplete cut.  That meant when the laser cutting was complete, I had to carefully punch out the 15 or 20 stubborn city blocks that weren’t completely cut though.

I also cut this design into a coaster, and made one with my old Massachusetts neighborhood too.  Naturally this was a lot of data on a small surface, but the results are pretty good despite the vector cutting time approaching that of the raster cutting time! I cut these at 100% power, 100% speed, like the other coasters.


After I completed all these steps, I learned about a way to access vector map data directly.  The Open Street Map site allows export of .svg vector data just by clicking the share button on the right side of the page!  Even better, one can zoom in to Milwaukee, and press the big green Export button on the upper left to export an .osm database of the visible section of the map.  This OpenStreetMap archive can be opened in Maperative! and a style can be applied to the rendered map.  Maperative has several styles built-in, and I simply edited the google maps-like style to omit all the buildings, and draw all roads, highways, on-ramps, etc in a black with no border.  Maperative can export .svg files, but I found the content of these files are a bit of a wreck.  For example, each different road type is a separate vector path, meaning that there are many separate paths in the file.  Ultimately I found I’d taken the wrong approach, as I should have rendered all the city blocks as black vector outlines, and omitted the roads – as that is what I really need to laser cut.  With a bit more work, using Maperative would likely be a quite quick path from map to laser cutter. However, I abandoned this approach as I’d already created a somewhat reasonable workflow.

Laser Cut Road Trip Coasters: Improved!

I used the Makerspace 60 Watt laser cutter to make coasters that show the path of some road trips I’ve taken.  That way I can enjoy the sweet irony of sitting on my couch enjoying a tasty beverage while having thoughts of travel!  This project was somewhat inspired by mmassie’s OpenPaths Zurich vacation keep sake project.

As I don’t use OpenPaths, I used Google maps to plot the course of past road trips, and simply took screen captures.  I wanted to create vector images with hairline width (0.001″) lines so the laser cutter can make each coaster in 45 seconds instead of 20 minutes. There are many ways to generate vector data using these raster .png images. I chose to semi-manually edit out unnecessary parts of the images using GIMP, and then used Inkscape to extract vector data from the resulting simplified images.  If you’re new to these tools, just search for “Inkscape raster to vector” tutorial videos.  An alternate approach is to just import the raster image into Inkscape, and use the Bézier line tool to trace the important paths.  Yes it is manual, but this alternate method also only takes 5 minutes to complete.

The coasters are cut from 3/16″ 4″ x 24″ solid basswood using fairly standard settings of 100% power, with 100% speed for etching, and 3.5% speed for cutting.


I made quite a few coasters, and above is a photo of three of them. The coaster on top is a rail trip through Italy, the second is a 1000 km, 12 day (right hand) drive through Ireland, and the last is a much longer than 12 day road trip through the southwest – note the vertical and horizontal lines are the state borders of NV/NM/CO/UT.

A few days later, after polishing my vector editing skills in Inkscape, I made an improved version of the above three coasters.  I added circles to more clearly highlight each stop, and I etched the names of each stop on the reverse side of each coaster.  One group of raster to vector settings I used in Inkscape resulted in the creation of two sets of (closely spaced) hairlines for the outline of Italy, as shown in the coaster above.  I really liked how distinct the outline of Italy is relative to the path of the trip.  I chose to intentionally create two offset hairlines for the other country or border outlines, using Inkscape’s linked-offset path command.

Check out the new and improved design of the front, with dual country/border outlines and circles to denote the stops:


Check out the reverse sides of these coasters shown below, with names of each stop etched on them. Albuquerque.


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.


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.


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.


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…


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.


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

Staying Stocked Up

The idea was simple: make something to help keep track of our supplies so we know when we’re running low on the essentials.  After weeks of kicking the idea around and various rough doodles, this project finally took shape.  Two days after the first cut on the laser cutter, it was complete.

Made from multiple layers of acrylic, cardboard, and wood, the “Milwaukee Makerspace Consumables Super Analog Status Board” is a clipboard-sized device with nine sliders installed in enclosed slots.  Sliding the tabs right displays more green to indicate “full” or “lots” and sliding left reveals the red acrylic below to indicate “empty” or “low.”  The user can carry the board around the Space with them as they check on supplies and when done, a large hole centered at the top allows the board to be hung up and displayed on a wall.

The hardware holding the whole thing together can be loosened and the layers disassembled.  The cardboard insert that the text resides on can be swapped out should we decide to change the list of items we want to keep tabs on.  The supplies being tracked currently include:

  • Toilet Paper
  • Paper Towels
  • Hand Soap
  • Welding Gases
  • Welding Wire
  • Propane
  • Soda
  • Duct Tape
  • Painter’s Tape

A digital version may or may not be planned for future release.

Tabletop Game Boxes

With Tabletop Day approaching and my great affinity for complicated rules attached to cardboard (see picture on leftDSCF0722 of what should be my linen closet) I thought it would be the perfect time to work on a few projects to improve some games that I much enjoy. On top of some other, smaller things I decided that the boxes that come with a great majority of card games are kind of worthless. Take for example. Gloom. A fantastic game in which you try to make your family as miserable as possible before killing them off in horrid ways all the time trying to make your opponents family happy so they cannot do the same (I realize I sound crazy but if you come down to the MakerSpace this Saturday I will have it so you should give it a shot. It really is fantastic). While the game is fantastic it came in was one of those that has the bump of cardboard in the middle between the two stacks of cards that is supposedly, in some fantasy universe where cards have different physics than everything else, supposed to keep them separate. This never works and the box usually breaks fairly quickly.

Being utterly fed-up with these boxes I decided to make my own for 3 games. Gloom, Cthulhu Gloom, and GOSU: Tactics. With the first two this also has the added benefit of being able to make the box large enough that I can fit expansions in with the base game and in the case of GOSU it is an opportunity to make a box that better fits sleeved cards and add a 3 turn counter to keep track of the round after the pass (If you have played GOSU you know it can get a little hazy when some people are taking a whole slew of turns per round).

After some playing with Inkscape, cutting out the first one on the laser cutter, realizing I suck at measuring, cutting things again, some gluing, and several layers of shellac later I had a few new boxes.

I had several people ask me how it was that I achieved this look on Baltic birch plywood so I thought I would go over that quickly. TheCGloom Box Open

inner part was just rag stained with some dark Minwax stain (I think it was Red Mahogany) so nothing special there but it adds a nice contrast to the lighter outside I feel. The outside is an amber shellac. I just applied 5-6 coats with a heavy sanding between the first two and a very light sanding between the rest. Nothing too exciting but it really makes this plain wood look pretty decent.



Makerspace rocks Sustainability Summit


Members of the Milwaukee Makerspace built and manned a booth at Milwaukee’s Sustainability Summit this week.

Josh Z. and Ben N. talked with the crowds, showcasing member’s projects ranging from an electric motorcycle to 3D-printing, aluminum casting, CNC woodworking, lasers, and more! Several of the event organizers told us that we were the busiest booth there, which was pretty obvious, because my throat is still sore from speaking with attendees for two days straight!

The 3D printer was especially eye-catching to the crowds and there was a strong interest in 3D printing and laser-cutting.

We did NOT have electricity at the booth, so in true DIY-style, we MADE our own with a real-world “Vehicle-to-Grid” Display, powering a laptop, 2 computer monitors and the 3D printer directly from the electric motorcycle. Our display featured a slideshow of Maker projects on the double monitors, the hands-on Laser Kalidescope, and even conductive Play-doh!

One of my favorite moments was speaking with the owner of the “Cow Sailboat” out in Madison about converting its diesel system over to an electric drive. We also briefly saw Ed Begley, Jr. and Will Allen. (Thanks to Growing Power for the sprouts!)

All in all, it was a great event! The organizers donate the booth space to us because they love the real-world, hands-on teaching and excitement that we bring!

If you were at the Summit, and are swinging over here to the web-page after learning about us, WELCOME! Stop on by, meet some members, and take a tour, we’d love to have you!

Thanks to Josh, Ben, Shane, Pete, and others that loaned projects for us to display!