Precision Coffee Roasting Gets Even More Precise With Help From the Makerspace


In an effort to improve the precision of coffee roasting at Swift & Finch, Mark McLucas upgraded the Victory 10 roaster by replacing the analog environment thermometer with a SOLO 4824LR PID controller and T-type thermocouple, which are capable of providing real-time temperatures within 1/10 of a degree.  The bean pile temperature is monitored by a near identical setup from the manufacturer.  He used the laser to cut an acrylic face plate and etch labels for both PID controllers, enabling him to differentiate between displays at a glance.

Precise monitoring and control of both bean pile and environment temperatures is
critical to producing clear flavors and a clean cup quality.  The temperature curves of both BT and ET move somewhat independently throughout the roast, and are manipulated through adjustments to airflow and gas charge.  Ideally, the two curves, though being 100-150 degrees apart at certain points, can be manipulated to move in tandem, the bean temperature gradually climbing to meet the environment temperature at the end of a roast.


To help with process control, he used the laser cutter to create a dial face for the gas control knob, making it easier to track and repeat exact set points procedures and train others in the fine art of bean browning.

To some, roasting coffee is considered to be a sensory operation: something conducted purely by watching bean color change, smelling for the development of compounds, and listening for first and second cracks.  However, the last few decades have brought about a more scientific approach to growing, processing, roasting, and preparing coffee, with roasting being one of the most crucial.  At the risk of sounding melodramatic (as is the inclination of some coffee professionals or people that fancy themselves as one), a coffee that has the perfect biological parentage, the ideal environment, and the best of care in growing, harvesting, processing, packaging, and transport can be blunted and even completely botched by roasting it without the same level of care and control.

All in all the project took approximately 6 hours, with approximately 3 hours spent designing the pieces and testing various laser settings to get the dimensions right, the edges clean, and the engraving deep enough.  The remaining three were spent on reassembly and testing.

What laser settings worked well? I found for the acrylic I used, a quicker speed (70), a lower power (35), and more passes (19) worked best for the vector cut.  I left the piece in place, added my engraving to the design, and ran the raster engraving back over the vector cuts as well to help clean up the edges.  Any pointers to other folks based on your experience?  Experiment a lot and be patient.

A well done laser cut is a beautiful thing.


Adventures in Vacuum Forming

I’ve been wanting to create some project enclosures that are not black boxes from Radio Shack (not that there’s anything wrong with Radio Shack), so I built a vacuum forming rig following an instructable:,-cheap,-upgradeable-sheet-plastic-vacu/

Here it is setup in the kitchen of 7hills Makerspace:


I found some channeled flashing at the hardware store that I made into the frame. I use 2×4 cutoffs to elevate the plastic in the oven, so it had a little more room to sag. A little over a minute at 400 degrees did the trick. Press the frame against the weather stripping, flip the switch, one giant sucking sound later you have a part:

I started out making a simple part. The mold was sawn, sanded, turned on the lathe, and then sanded some more. I was surprised to see the wood’s grain still showing through. I cut off the excess and added some self-adhesive vinyl. Here’s how it turned out:

It’s not perfect, but it was a pleasing first attempt. I’m planning to make a bottom enclosure from bent acrylic. That’s one more thing I’m learning about as I go.

The next thing I wanted to try during my inaugural molding session was an experiment to see if you can create molds on the makerbot. Would the two plastics stick to each other making mold release difficult? The answer is … no. The makerbot-made molds did not stick to the sheet plastic. However, the surface imperfections typical with makerbots was visible through the sheet plastic. The results show that with numerous small parts, I should have paid more attention to airflow and bridging/webbing.


So there you have it. I felt pretty successful for a first try, but I have lots more to learn about vacuum forming.

“Hello World of Making” Project

When learning a new programming language, you start by getting the computer to display “hello world” on the screen.  It is a preliminary confirmation that you can do the basics of the programming language.  With a new makerspace like ours, lots of visitors and future members will want to learn what can be done in the space and how to do the basics on our machinery.

In order to help them, I have tried to design a single project that costs just a few dollars, and that uses a diverse set of machines available at 7Hills Makerspace.  The project is not a fancy high-tech, Arduino based device; it’s a flashlight (and not even a good one at that). It uses 3D printing, circuit board etching, soldering, and laser cutting. It is essentially a “hello world” project for new or future makers.

Hello world flashlight picture

The Hello World of Making" Flashlight

The body is 3D printed (here in red ABS); as is the “on” button.  The top and bottom are laser cut 1/16 inch acrylic.  The top is etched to read “Hello World of Making,” the bottom has the 7Hills Makerspace written out in text and the logo is displayed. The electronic components include a CR2320 battery, battery holder, a resistor, an LED and a push button.

Exploded CAD drawing of flashlight

Exploded view

Flashlight off




The project is still a work in progress.  As you can see, some of the holes don’t line up right yet and expediency lead me to use a yellow LED.  future versions will have bright white LEDs (because I will have gone to the store by then).  I also plan to think throught the processes that are use and schedule them so that waiting time for one project is utilized to get another process started.  For example, while the circuit board is being etched for 20 minutes, Laser cutting and etching could be introduced and started.  While the 3D printer is finishing, Drilling the PCB and soldering could begin.   The goal is to have the build to be of managable duration, not to rushed, but not boring or tedious either.

This is a first attempt.  I plan to change it and improve it.  I would love to hear your ideas about how to make it better.

Hello World of Making!




Pano Virtual Tours

Over the past few months, I’ve been playing around with using panographic and spherical photography to create interactive, virtual tours. I thought I’d post an overview of the experience here, and provide some details of the tools and process I used.

First, I’ll provide links to three of the test shots I did so you can see what this looks like when it’s put together.

Rome Area

Bird Trail

Industrial Building

Creating these tours is a three step process:

First, you need to create a series of photographic images using a wide-angle lens. For this part, I followed this great tutorial. You don’t need a fancy camera for this. In fact you can use a simple point-and-click, although a nice digital SLR and a really wide angle lens will really make things pop.  And if you don’t use a wide angle lens, you’ll just have to create more images and stitch them together to get a full 360.  For the above, I used a Canon 5D Mark II camera and a Rokinon FE8M-C 8mm F3.5 Fisheye Lens.

Next, you have to do some post-processing of the images captured in step 1.  Basically, you need to “stitch” the images together to create a single panographic image, or depending on your needs, multiple, tiled images that fit together to create a spherical panorama. For this, I used software from PTGui. You can find some great resources and tutorials on that site. There’s also an open source alternative for this called Hugin, but I haven’t worked with it.

Finally, you have to prepare and publish your creation on the web. There are many ways to do this, but I chose to embed them in a Flash Player using krpano Viewer. the same company also provides krpano Tools, which is basically a framework for creating all the controls, screen elements and effects you see in the examples above.

That’s the nickel tour. I hope you’re all motivated to go create your own tours! I’ll be doing some new shoots for one of our customers over the next few weeks and will post follow-up notes.  I’m also hoping to do a spherical video soon.