About Lois Holman

An exchange student from the University of Birmingham, I am a double major in Mechanical and Materials Engineering.


This post is here for easy navigation of my work over the past few months. For individual posts, see below. For my full blogroll, see here.

Getting started, and miscellaneous posts

“Hello World”, the maker community world

Beauty in Equations

Ready steady GO (expiriences in learning Fusion 360 CAD)

Getting going, lets 3D print!

Tying up a few ends (miscellaneous side projects)

“How to… ” Join me on my skills series

How to… Laser Cutting
How to… Arduino
How to… Soldering 
How to… 3D Scanning
How to… Engrave Glasses (semester post)

“Time…” A semester project

Part 1: Time for a semester project? (this post)

Part 2: Progress through time

Part 3: Tick tock goes the clock

Part 4: What’s in a face?

Part 5: Closing Time

Closing Time

Part 1: Time for a semester project?

Part 2: Progress through time

Part 3: Tick tock goes the clock

Part 4: What’s in a face?

Part 5: Closing Time (this post)


Rounding up my “time” posts, this is my final prototype for my project.

Here (below) is my final prototype functioning. You use your own hands as the clock hands, and the shadow cast by the LEDs tells the time. When the clock is not triggered, it acts as a light installation.


Heres how I’ve incorporated the different skills from the semester into my project:

  • Soldering: hours upon hours with the soldering iron putting together those LEDs, wires, and components.
  • 3D-Printing: printed gears for a mechanical clock idea (didnt make it onto final design). Designed on Creo after an unsuccessful attempt on Fusion360.
  • Laser Cutting: created an interlocking box enclosure to house all the components. Designed using inkscape.
  • Arduino: wrote code from scratch for the interactive nature of this clock.


For future iterations, things that i’d consider doing:

  • diffuse the LED light so that its a softer glow, maybe with a fabric covering
  • reset the time code at midnight so that theres no chance of it hitting problems from constant running
  • hinged lid for easier access to inside components, or better press fit box
  • overextend the lip or mount LEDs much further into box, so its not possible to look at them directly
  • the code could be rewritten to be more efficient
  • troubleshoot to ensure every single permutation is correct.
  • laser hole in top back for a nail to hang on a wall
  • determine optimal angle  to trigger the ultrasonic sensor.


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What’s in a face?

Design, ideas, progress, challenges, and workarounds for my semester project. Part 4 of 5

Part 1: Time for a semester project?

Part 2: Progress through time

Part 3: Tick tock goes the clock

Part 4: What’s in a face? (this post)

Part 5: Closing Time

With the functionality implemented on a working prototype, the last few stages are aesthetic.

I designed the casing and enclosing structure to be in the style of a press-fit laser cut box. These are something that I really liked the look of and wanted to have a go at creating.

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examples of press-fit boxes


I designed it in the editing program Inkscape, and have made it out of 1/8” wood.

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Hand drawing a box design. Hoping it will fit together!

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laser cutting the design

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putting the box together

I built in a platform to raise the level of the LEDs so that they would cast a general glow, instead of seeing point lights. (point lights are visible if it is mounted directly onto the base).

While the box does interlock, I didn’t design it to take into account the material that would be removed when the laser cuts, so it does not “press fit” together on its own. A glue gun fixes everything though.

On designing the clock face

Tying in with my equations, and “world fundamentals” theme, I wanted an equally relevant clock face.

A lot of ideas that I came across involved using numbers that numerically evaluated to the clock face number:

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clockface examples

These were fun, but I wanted each number to have a deeper meaning. The result is a clock face where each number is relevant to a different mathmatical theorem. The majority of this clock face was found online.

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My clock face

Each number is related to a theorem, if you’re curious…

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I have this description rastered onto the back of the clock



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Ta daa!!


“I can run, but cannot walk. I sometimes sing, but never talk. I need your hands upon my face, for you to check me, to keep your pace”.


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Tick tock goes the clock

Design, ideas, progress, challenges, and workarounds for my semester project. Part 3 of 5.

Part 1: Time for a semester project?

Part 2: Progress through time

Part 3: Tick tock goes the clock (this post)

Part 4: What’s in a face?

Part 5: Closing Time


Prototype 2.

Simplifying circuits is how I’m going to fix things. Prototype 1 tried to incorporate 2 colours of LEDs, with only 12 IO points. Simplifying the design, I’m reverting to a single colour of LED, which does not call for the circuitry to be as complicated.

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circuitry works! Just the code to rewrite now then.

The LEDs can light much brighter in this configuration, so i can have greater spacing in my clock face and go for a bigger frame.

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working on framework of prototype 2

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Detail of LED positioning

A little spanner in the works at this point: the time code stopped running on the device. With a lot of help and troubleshooting, the problem was located as a dodgy connection in the hardware, not a code issue as originally expected.

Coding shenanigans

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Editing code

My code has also been through a series of iterations. It requires 3 files to be run:

  • setting the time on the time device to sync with my laptop
  • reading and checking the time on the time device
  • running the LED commands based on the time on the time device


Since I couldn’t utilise 2 colours of LEDs, I’ve opted to include a proximity sensor to detect when the time is being checked. The design is now that it only becomes a clock when the sensor is triggered. For the rest of the time, its a light installation.

Heres the testing of the proximity sensor:

Note how the shadow cast by the pencil makes the hands of the clock and tells the time


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Progress through time

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Design, ideas, progress, challenges, and workarounds for my semester project. Part 2 of 5.

Part 1: Time for a semester project?

Part 2: Progress through time  (this post)

Part 3: Tick tock goes the clock

Part 4: What’s in a face?

Part 5: Closing Time


Realistically, there’s 2 routes I can take with creating a timepiece. Predominantly mechanical, or predominantly electrical. Cogs and wheels or LEDs and circuits?

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Progress milestones and challenges:

early design and prototyping days

  • I started off by brainstormed ideas for a clock design that would utilise many making techniques.

Fixed design

  • With my love of the outdoors, the way the world works at the most naturalistic level, the fundamental equations and the beauty that can be seen through them, I feel that merging old time-telling techniques with modern techniques is a particularly fitting final project for me.
  • In the brainstorming process, Vishal suggested some form of interactive nature for the clock. I originally thought about proximity sensors to activate a screen displaying data or something (as an additional feature besides time-telling). The idea that I’m running with is that I want to keep a simple elegance about the design, in keeping with the simplicity of the concept. No need to clutter it with unnecessary features for the sake of making it sing and dance.

Looking at various mechanical designs as inspiration:

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  • At first I printed some gears to see how feasible it would be to produce a mechanical-based clock.
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Playing around with gear design and 3D printing gears

I found that the gears did not mesh well, and that it would be difficult to get smooth motion out of this.

I then considered possibilities with LEDs and circuits:

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Different design approaches for LED clocks


Settling on an idea:

  • What I’m creating is a a clock face that relies on shadows to be the hands of the clock. Different LEDs in a ring will light based on the time, and shadows cast by those LEDs will show the time.
  • A similar concept was created as a design project in germany
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concepts that i want to play around with


I got a time-keeping device working and talking with the arduino after some code bashing attempts. I’ve also managed to write some other code for the lighting of specific LEDs based on the time it reads from this device.

It utilises 2 rings of LEDs, with 2 separate colours. With a single arduino, its only possible to have 12 positions for LEDs. For more LEDs (ideal would be 60), a much more complex circuit would be required, with the use of charliplexing and many more man-hours of soldering and complexity.

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From this diagram I can see that theres only 23 I/O pins, so my design is constrained to that


Working with the limitation of 12 IO pins on the arduino, I developed circuitry where each position has 2 LEDs in series wired like so:

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The concept works on a breadboard. While a low power is constantly running through, so the LEDs are low lit when not engaged, when the LED is chosen to light, it is significantly brighter than the others.

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During the soldering process


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The parts are all soldered here, and wired up for testing. Unfortunately, with so many LEDs in the circuit, I found that the LEDs that should light brighter than the others do not have enough power to do so.

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Testing the LEDs

Back to the drawing board.


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How To…. Engrave Glass

A post on my experiences and observations while rastering glass, and the methods I followed.

Refer to my first laser post (How to… laser cutting) about the general use and basics of laser cutting.
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Here, I’m looking specifically at rastering images onto glass. (The lasers that I’m using aren’t strong enough to vector cut through glass.)
To get a clear, well rastered image, settings have to be fine tuned, because the power speed, and laser movement vary per laser cutter. These settings also differ between the glass that you are restoring onto, since different glasses have a different composition and impurities.
Screen Shot 2016-05-12 at 21.04.22
The final rastered pieces!

Procedural steps:
Preparing an image for rastering (using Inkscape as an image editor)
  • Determine the size of the glass face that you will be putting the image on, and create a document of that exact size.
  • import your image in, and convert it to a vector file (black and white)
  • convert the image colour to 50% grey. This helps preserve the integrity of the glass and does not cut as deep. It also creates a “whiter” finish
  • (optional: tidy up the image)
  • place the image in the location wanted
  • export file as a PDF and save to a USB drive
Using the laser
  • turn on all fans and ventilation equipment
  • check laser is calibrated correctly and focus the laser, if not using the autofocus
  • open file on computer linked to laser cutter, and hit file, print
  • depending on laser cutter, settings are adjusted differently. in advance settings, select rastor, setting power to 100, and speed to a value between 20 and 40%
  • hit print on the computer, and on the laser machine.

Experimentation and learning:

Particular selections that I had to make were selecting rastor instead of vector cutting, setting the highest power possible (100), and testing various speeds and restoring styles to get the best finish.
I tried a series of test combinations:
black image, speed 50
black image, speed 40
50% grey, speed 40
50% grey, speed 30
For rastering my image, I found that a grey image at 25% speed worked best, and for rastoring text, black at 30% worked best on this glass. Also tried using grey text at 30 and 25%, but they both leave areas not quite fully rastered.
Another experimental point is the way the motion of the rastor cut: this was the difference between “standard” and “jarvis”.
 Screen Shot 2016-05-13 at 09.28.56Screen Shot 2016-05-13 at 09.29.06
 standard vs jarvis
Rastering circumferential surfaces:
 The previous experimentation was all done on a flat surface so that the laser draws a flat image. To be able to raster onto a circumferential surface, a special jig must be used to rotate the surface as the image is engraved.
Depending in jig setup, a number of constraints must be considered for optimal engraving.
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Non-varying diameter with no external protrusions is the best shape to use
for a circular glass.
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examples of suitable glasses 
 Here is an example of a very inappropriate glass, which would not be possible to rastor onto easily:
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Features that make this inappropriate are:
  • handle will get in the way of the laser when the glass rotates, so a workaround would need to be considered in terms of the engraving space.
  • the base rim means that the glass does not sit level, which it needs to do for uniform rotation.
  • engraving area has to be planned very carefully. if it were a blank glass then it wouldn’t matter, but if I want what I’m engraving to line up with what is already on the glass, then careful measurements have to be made.


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“Time” for a semester project?

So here it is: design, ideas, progress, challenges, and workarounds for my semester project. Part 1 of 4. ***(note at end of post)

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Sneak preview… So can you guess where this is heading?

My project, what is it?
Over the last semester we’ve been introduced to an array of techniques. A theme I’ve tried to keep in my own work and posts has lead from my very first posts on the beauty of equations; the natural world and pure concepts. This resulted in my climber key hanger, coin trap, and interest in mathematical shapes. An area of these pure concepts that I’m interesting in developing into a project, is time. A timepiece, a clock device, is something I can design and create, where I can draw on combining a range of the processes and techniques that I’ve tried out this semester.

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Talking with a classmate (Steve), I came out with the line: “It’s going to be a clock, a wonderful clock, a really really great clock. I bring you…. a clock that trumps all other clocks.” I’m aware that saying “I’m making a clock” sounds like quite an anticlimax, considering the plethora of possibilities that we can work on, but its definitely something that I can develop to touch on most aspects of making that I’ve had access to. I want to use my final project to build on, and demonstrate these skills/techniques.

Looking at ways to jazz up a clock and add aditional functionalities, considerations include:

-sensors to interact with its immediate environment?

-feeds from online data?

-electronic circuits sewn into the face of the clock for visuals?

-motor motion still with arduino?

-led stuff?

Browsing online for unique clock concepts as inspiration and an initial hunt for ideas:

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Passing of time on this calendar is demonstrated through the slow capillary action of the purple ink

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Classic circular clock face with unique designs that utilise different interactions and concepts for denoting time


***(Sorry Vishal: I went down the route of powering through, redesigning and adapting until I have my final piece, without stopping to write about it until its done. Documenting it now instead of as I go along means this is a more cohesive piece of prose and takes less time away from the creation of the project!)


In this series of posts:

Part 1: Time for a semester project? (this post)

Part 2: Progress through time

Part 3: Tick tock goes the clock

Part 4: What’s in a face?

Part 5: Closing Time

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How to… 3D Scanning

How to… Laser Cutting
How to… Arduino
How to… Soldering 
How to… 3D Scanning (This post)
3D Scanning… What is it? As the name says, its the scanning of a 3D object, and can be done with fairly basic technology. It works through the process of laser triangulation, using a sensor to pick up reflected laser rays.
Its very popular commercially as personalised gifts: busts or even whole bodies can be scanned and printed.
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Printing in different materials even allows for different colours to be printed on a model


Simple camera attachements like this iSense scanner can be added on to existing technology to create the scan.
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Here 3d scanning has been utilised in a novel way to produce a quirky iPad stand.

More expensive scanning devices do also exist, with more accurate laser and sensing technology for finer detail scans.

General workflow for producing a 3D print from a 3D scan:
  • scan in image*
  • using Autodesk Meshmixer to clean and tidy up the scan, scale image to sit on the dimensioned printing bed
  • use edit and sculpt functions to smooth out blemishes on the scan (e.g. smoothing out hair on a bust)
  • Add a base for the print by selecting from primitive shapes
  • autorepair under the analysis inspector section, to fill in any holes on the scan
  • combine all shapes, and save as an .stl file to be imported into Cura for printing

*scanning the image is the hard part! Very easy for the scanner to “lose track” of the object


For this exercise, I wanted to create something functional from my 3D-scanning. Scanning a bust is a very common use of basic 3d scanning, so I wanted to experiment with a more challenging scan.

My aim was to scan a outstretched hand and arm, with the goal of turning it into a unique and customised coat-hook or key-holder, like these:

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I want to create something like this, using 3D scanning

Since busts are a common use for 3D scanning, the software we were using had algorithms written in to be able to pick out the head shape for a scan, and has optimisations in place to pick up the head scan as smoothly as possible.


Building up a scan image by rotating head and shoulders on a spinning chair

A particular challenge was getting the scan software to recognise the hand as the item to scan, and not everything else in the background.

Once the scan started picking up the hand as my object, the difficulty was in rotating the scan-camera round the hand to get a full 3D image. It works well for a bust because when sitting on a chair, the rotation has the head at the centre of the axis. I found it very difficult to have the centre of the scan object at the centre of rotation. Its hard to rotate an arm about the same spot!

There were many failed scans that looked similar to this:


Many scans later there was a better one that was incomplete, but had enough framework in place that I could then build up the missing parts of the hand using Meshmixer.

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After some editing and little fixes (recreated and extended some fingers!), I managed to create this:

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It worked! 3d printed hand scan


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How to… Digital Embroidery

How to… Laser Cutting
How to… Arduino
How to… Soldering 
How to… Digital Embroidery (this post)
Digital Embroidery… what is it? Producing stitched pictures from a computerised image. This is set up through a program called SewArt (not open source). It converts a graphic into a stitch file that can be read by a sewing machine.

Rough digital embroidery workflow:

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  • open image in SewArt
  • paint pallette icon -> Select the number of colours to reduce to. These are the different thread colours that you’ll be loading into the machine.
  • blocks icon -> This is to help tidy up the colour selection. By using “merge” colours, and “despeckle”, it tidies up the image
  •  sewing machine icon->  This lays down the stiches. Choose the order so that you don’t switch thread too much, manually selecting the row stitch type and pattern
  •  save the sew file as a .pes, with a 3.9 inch maximum image size to fit in the machine
  • connect the machine to a laptop then drag and drop the .pes file into the “removable disk” of the sewing machine
  • thread the thread through the machine following the numbers, finishing with push down button 9, and pull through the loop that is created
  • check the white bobbin thread is loaded, check tension dial is set to 0. This stops the white thread getting pulled through. Put the foot down, the needle down, then hit the green go button!
  • When a colour is done, cut the thread, move the foot and needle up, then change thread as before

If the stitching goes wrong in some way and you need to stop and cut the thread, you can adjust where you are in the sewing sequence, using a +- through the stitches and colours.

Things to watch out for (easy tripping points):

  • choosing the stitching correctly in SewView
  • don’t be too ambitious with many colours
  • don’t use small text
  • don’t knock it or move it when it is sewing
  • watch out for tension, so that white thread is not getting pulled through the fabric


Knowing this was coming up, I looked round for embroidery uses and patterns.

While brainstorming for uses of embroidery, I drew up quite a blank. At first consideration, it has no physical use, and is just for aesthetic purposes.

I was looking for designs where the embroidery could be turned into something functional, and not just be something to look at, resulting in my first consideration being embroidered headbands and small adornments:

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Searching for embroidery inspiration

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Some patterns that I considered for a headband. Conclusion: too ornate and complicated to reproduce.

The closest to a functionality I could think of, was to convey information through pictures and design.

This is exactly what clothing patches do: decorate a garment, and are often used as logos. Who does this better than NASA? They have a mission patch for everything, and those mission patches are the most iconic use of embroidery. So much history and importance is associated with a simple embroidered patch.

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While iconic, this has a few too many colours for me to attempt for my first piece of embroidery, so settling on the NASA logo:


Knowing that simple shapes, and few colours are the key to a well made embroidered patch:


also made this Deadpool. Perfect design for simple shapes, minimal number of colours.


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Tying up a few ends

Reflecting on this week, it’s been pulling together the final parts of quite a few pieces that I’ve been having a hand at: a bit of “this and that”, and a few mini-projects along the way.


I recently came across the concept of coin traps, and used Fusion360 again (Ready, Steady GO! for my first shot at Fusion360), to design one that would fit a dime. These are great for demonstrating the additive nature of 3D printing, because you have to pause your print part way through to add in the coin, before allowing it to continue and create the enclosing case around the coin.


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I CAD-ed up my own model of this to practice some dimensioning and to see how many steps it takes- 18! (a handful of those are just chamfering the edges). My design is for a 17mm diameter coin. This can easily be scaled up and down when using Cura, to create coin traps of different sizes.


A throwback to one of my earliest posts Beauty in Equations, I found this blog recently of 365 days of prints, ‘a print a day’, and it demonstrates a interesting selection of mathematical prints:

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1) pencil sculpture created through using 3d printed supports        2) knotty mathematical shapes

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3) trefoil knots as a 3D puzzle                                    4) demonstration of stereographic projection

(mathsy explanation  of stereographic projection here!)

The blogger uses a special program to conceptualise the mathematical models, before converting them to .stl files for 3D printing.

In my post on 3D printing (Getting going, lets 3D print!), I highlighted some fun things that can be designed and printed using PLA 3D printing.

Here’s my own take on one of them. It’s a key-hanging device, designed in Fusion360 and printed at the Illinois Makerlab:




More recently when we started playing around with electronics, I procured a few extra components and have made my own LED lamp.

The base structure was created in Fusion360, and printed using supports to maintain the dome structure.

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A breadboard frame would have been easier, but I’ve used cardboard for basic LED positioning.


The rest of the innards are held together with a combination of electrical tape, sticky tape and white tack.

End result worked out ok though!

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