Intro to fabrication – Mounting Motors

This weeks assignment was to create a project involving a motor. This could be either a servo motor, stepper motor or DC Motor.

My idea for this weeks assignment was to make a “Useless device”. The initial idea was to create a button you would press. This button would turn on a motor which would press another button and a light would come on. The actual challenge would be to mount the motor onto something and attachment to the shaft of the motor.

This is a cardboard version of what my initial plan looked like. Spinning a circle attached to the shaft of my motor would extend the reachpoint of an arm. This arm would hit a button and turn on a switch.

The pieces would be cut out of acrylic and I would attach the parts using mechanical screws. After talking to a few people I realized that the many pieces in the plan would cause a lot of friction – making it difficult for my motor to create enough torque. For that reason I decided to create a more simplified version of the idea – taking out a few parts. This is what my new plan looked like. Basically, it would be the same concept as my first idea, but it would have fewer parts.

First I needed something to mount my motor onto. I found two pieces of leftover wood in the shop and cut them on the Miter saw. I then layered them, so that if I drilled a hole thorugh them they would cover up my motor – and keep it in place. Since the motor had an awkward shape i chose to drill two holes next to each other and file them into one shape where the motor would fit. This took a few practice attempts.

First practice attempt to make a motor-shaped hole in the wood:

Cutting the actual holes in the two layered piece of wood:

Filing and fitting of the motor. Practice attempts on the right – fitting adjustment being made on the left.

With the DC motor was now mounted to the wood, I would have to attach something to the shaft. I measured the dimension of it and cut a circular shape out of acrylics on the laser cutter. This circular shape would have a hole in the middle that would fit onto the shaft of my DC motor. Additionally, I cut a rectangular shape which was intended to go onto the spinning wheel and function as an arm turning on and off the light switch.

Everything was going well and this is what my “useless device” now looked like:

I connected 6V to my Motor and found that it was spinning really fast (a lot faster than I expected). So instead of 6V I tested 3V and found that the motor moved at a slower pace. The speed was now well suited for what I had intended for this project. The problems started to occur when I mounted the acrylic pieces to the motor. The motor now wouldn’t move. I assumed it was because of the low voltage supply to the motor and changed it back to 6 volts – also this time I added a potentiometer to the circuit to control the amount of voltage going into the motor. I could now control the wheel attached to the motor shaft without problems.

Testing different voltage-supplies and potentiometers for the circuit:

I then tried to reattach the acrylic pointer to the wheel. Also I found two pieces of wood that would go onto the device to limit/control the movement of the pointer/arm intended to touch the switch-button.

My “useless device” had now turned out to be exactly what I had in mind to start out with:

The motor would spin the wheel and the pointer would hit a toggle switch located exactly at the end of reachpoint of the “pointer”. The only problem was that it didn’t work. Every time the pointer was attached to the wheel it would either stop spinning or go very fast depending on the amount of voltage applied to the motor. Additonally, some parts of the circuit would start to get overheated.

Frustrated, I figured that the pieces controlling the movement of the “pointer” was maybe too narrow. For that reason I broke them off and tried one more time with two new on pieces that would allow for more movement of the pointer and (maybe) less friction.

However, this provided the same issues as before. The motor would either spin very fast (with a high voltage supply) or not spin at all. Mostly, it would spin a few rounds and then stop. I tried many different constellations – changing the voltage supply, changing the position of the pieces controlling the movement taking parts on and off. But nothing seemed to work.

The best explanation I can think of as to why this doesn’t work is the DC motor. I should have probably used a more powerfull motor. What really surprised my though was how well it worked with just the spinning wheel as opposed to mounting the “pointer” to the device – where it didn’t work at all. I was really happy with the mounting of the motor into the wood and the mounting of the wheel to the shaft, but the movement of the pointer didn’t end up the way I wanted it to.

Intro to Fabrication – Materials and fasteners

For this weeks assignment I tried a few different things – not everything was succesful, so I had to change my idea a few times. For my PCOMP final I am building a wearable strap that measures respiration, however I have not yet come up with a good solution as to how to cover the cables that goes into the fabric. So for this assignment I wanted to make a case that gets covered in fabrics.

This was the starting point:

For the case I went down and bought some mints and toothpicks as these cases had the size I was looking for to hold my boards. I later realized that in order to later acces the board again, I would have to go with the toothpick case. This case had a plastic circle in the middle that I cleared using a wirecutter to make space for the boards.

I then used the metal nippler to create passages for the wires going to and from the board. And as this didn’t work out well I also tried drilling holes (I knew the case was going to be hidden by fabric – so the rough look didn’t really matter). I started out with a smaller drillbit and gradually increased the size. However, for the head of my battery connection to fit I realized that I needed the passages to be quite big.

At this point I realized that making the holes fit for me to access the board, switches and battery was going to be very difficult. So at this point I decided to 3d print a case instead. After finally finding the time and a 3d printer that worked I printed a case to contain the electronics. This took a lot more time and effort than I had expected.

After a lot of soldering and adjustments to the board I managed to fit the switch, microcontroller, bluetooth and polar pulse sensor into the enclosure.

The next thing I wanted to do was to create an enclosure to hold the case. I wanted to make this enclosure out of fabric – so that it could be sewn into my bigger chest strap;
First I measured the dimensions of the case and outlined it on the fabric

I then connected the sides using thread.

When both sides had been sewn I cut of the excess fabric and turned the case “inside out”.

Although some things could have been done more precisely I’m very happy with the outcome. Considering what I started out with – my final case/enclosure will work really well in my final device. Also, I got to try some different materials and new techniques.

Intro to Fabrication – Enclosures

For this weeks enclosures class I wanted to redo the case of my PComp midterm. When presenting this project a few weeks back I was happy with the project, the enclosure however was absolutely horrific. At that point, I remember wishing I had taken this class earlier as people who had worked with this brought some amazing products. This is what my cardboard case looked like (I convinced myself that I was saving the planet by not using acrylic).

That thing could win ugly of the year award. Anyways, this week a went to canal plastic and realized how many different colors the eye can see. After that I went to the container store had a similar experience – this time with boxes. I bought a standard bamboo box with some doubt as I had to drill some holes into the box – and since the boxes seem a little fragile I didn’t know if that would be possible. I needed to make a hole on the side for an ultrasonic distance sensor which was the first thing I started working on.

I got a quick tip from Ben. He told me to use a Spade-bit? One of these round bits to create big circular holes. Also, I thought it would be a good idea to clamp some wood to either side of the box to avoid the bamboo from splintering.

This worked a lot better than I had expected and the two holes separated by an inch fit well with the ultrasonic sensor.

Next, I had to create an Illustrator sketch to use with the lasercutter for the acrylic top of the box. I made room for a switch and a light – just like the original box. In order to do this I had to measure the individual parts which was done using last weeks “tool of the week”: the caliber (or the “Fancy scale” – as I like to call it).

Also I had to create another spacing for an ultrasonic sensor pointing up. During Pcom midterms one of the things pointed out when presenting my project was instructions. My previous box didn’t really provide any instructions except for a couple arrows. I was considering this when making this design – trying to come up with a way to illustrate the gestures that were intended for this project.

Before making the actual cut in acrylic I made a test sample in cardboard. This was useful as I needed to correct the holes for the ultrasonic sensor a bit. After that I cut the actual thing in Acrylic.

I cut the acrylic 3-4 times. A big mistake I made was only to etch once. It looked great through the glass in the actual machine. However, I later realized that the etching was very hard to see. For that reason the instruction images didn’t really come through – I tried using a sharpie to color. That helped a little – but still not to a degree that I’m happy with. So I will give it another go this weekend.

The image shows my final enclosure. I mounted a toggle switch and a light which provided a good finish. Aside from the ecthing error I think it looks good – especially, considering the first prototype.

Intro to Fabrication – week 3 – Laser Cutter

This week in class we talked about measurements and the many types of scales that exists. We were introduced to the beautiful world of the Laser-cutter and saw a lot of different cut-outs made in acrylic and wood using cutting, etching, coloring and bending. Our assignment this week was to create something using the laser-cutter. I decided to create a bookstand but wasn’t sure how exactly to create a simple design. So I tried to draw different sketches out. If I potentially had to use screws I didn’t want them to be visible – which made everything rather difficult.

Eventually I found this design on the internet and wanted to do something similar.

The first thing I did was to try to create the pieces in cardboard. I used a knife to cut out the elements and put them together to see if the pieces would actually work and if the dimensions of the pieces were suitable for a bookstand.

At first, my intentions were to glue the pieces together so they would stay in place. I then realized it would be better to have a stand where the two parts could be taken apart again, if for some reason it needed to. This is what the elements looked like and their dimensions:

The hole in the element to the left was intentional. Instead of using glue I was hoping that when the two elements were collected together putting something through that hole (piece of wood) would lock the pieces in. That way the two pieces could always be taken apart again.

 

I created a file in Adobe Illustrater using the specified dimensions and inserted the gaps to make the pieces fit each other. I then went to the laser-cutter to print them out. First obstacle I met with the laser was that my piece of wood wasn’t flat. The dimensions in the printer is 24in x 12 in and I cut a piece according to that but the wood had a bend and needed to be cut into smaller pieces.

I then cut the pieces out (The wood needed four rounds of cutting – using freq 500, time 15, power 100) only to realize that the pieces didn’t fit. The space I had created for one element to fit into was too small. Rookie-mistake, I had created a hole in one element that was exactly the measures of the other element – and it clearly didn’t fit. I created another element but this time with more space for the second element to fit in. And even though the dimensions this time was (somewhat) larger than the first time the elements still didn’t fit. I figured the only thing to do was to sand it down.

After a while and a lot of sanding and a lot of struggles I managed to fit the pieces together. As you can see from the back of the T-element – it took a lot of sanding to make the pieces fit. We were told that the laser-cutter wasn’t 100% accurate – today I saw that with my own eyes.

If I were to make this project over again (I might) I would change the dimensions of the gap for the T-element to fit into drastically. I would make sure I left a left of extra space for the pieces to fit together. This would save me a lot of time and make the project look better.

Question – what wood is better to throw into the lasercutter? What types of wood doesn’t bend a easily as others?

Intro to fabrication week 2 – Repeatability

In this weeks class we were introduced to different clamps, saws and sanders in the workshop. More specifically, we were taught how to use the band-saw, the sander and the miter saw. At first these machines seems rather intimidating – but you quickly learn to become more confident using them for your projects. The main theme this week was Repeatability which meant we had to produce 5 of something for next weeks class. This assignment has become quite a thing at the ITP floor known as one of the assignment that consumes a lot of time. I knew I wanted to make 5 frames this week -although some alarm bells rang – apparently it is difficult to make things straight and align corners. This I would soon find out.

First I had to realize that standard dimensions of paper in the US varies from paper in EU (of course it does. Like everything else). So my idea of making 5 standard A4 frames didn’t make much sense. Instead I based my dimensions on the so-called US-half letter which is approx. 14.9 cm x 21.6 cm. I had some difficulties finding the right material to work with. At first I tested some wood that I had from a previous project. The problem with this wood was that it had to be cut in half (at least) – which was an impossible task. I used the band saw, aware of the fact that I wouldn’t be 100pct straight – but it was really bad.


This is my attempt to divide the piece into two equally sizes portions.

Instead I looked for a material that had the appropriate thickness

However, this piece still had to be cut into several straight pieces that could be used as the different panels in the frame. Although this piece was easier to cut straight using the band saw – doing it like this would be time consuming without providing very good results.

Instead I took one of the well cut pieces with me to find wood that was already cut into panels of the right size. All I would have to do then would be to cut the edges into 45 degrees and connect them. I found some wooden pieces in the right dimensions in “Blick”. I first had to measure some “prototype sticks” that could serve as a template for the rest of the frames. I found that the edges, when cut in 45 degrees on the miter saw would be 1.3 cm which I then added to each side (bottom, top, left, right side) so that the actual picture size would be US half letter. See image for measurements.

It took some time to get the first set of panels to fit into the right sizes (first pancake). But when that was down, it went faster with the rest of the panels. Having a template however, does not guarantee similar results. I had to adjust the sizes again and again to make the panels the same size. This is what it looked like at one point – although I had used the same template for all of them.

Instead of correcting each individual panel I later realized that I could have simply taped the sticks together and cut them all at once – to make sure they had a similar length.

With the panels down (10 side panels and 10 top/bottom panels) I sanded the rough edges that the miter saw had left on the pieces. Although I did not fully trust the 45 degree mark on the miter saw it worked pretty well. What was more difficult was to get a clean cut from the saw without curves or bends in the wood. Sanding the edges helped align the part of the panel that would connect in a joint.

 

Glueing the pieces together went well. I used the 90 degree corner clamps to collect the pieces. My frames were to small for me to use more clamps, so I had to piece together one corner at a time.

 

With the assembly being done i put some wood filler into the front part of the frame to smoothen out some of the areas where the connection of the joints didn’t look good. Also I removed leftover glue and wood filler from the inside corners of the frame, as I imagine it will be difficult to sand down when dry.

My plan tomorrow is to sand down the frame to get a smooth transition from one panel to the other. Also depending on the available colors – I may color the frames before class.
Ideally, I would have 5 fully functional frames. But instead of just glueing a background panel to the frames I will try to think of a smart solution so whatever is being framed can eventually be replaced.

Intro to fabrication. Week 1. Flashlight.

This was the first week of the “Intro to fabrication” class. I am really excited to learn some basic crafting skills and I have seen people do some incredible work using the tools from this class. We were introduced to Ben Light, tool of the week (a spring loaded punch), safety protocols, the website and some tools for drilling. Also, the homework for the week was to create a flashlight. For this assignment we could do whatever we wanted – only rule was for the flashlight to be portable.

Let me start out by saying that for this assignment there was a lot of “first time”. I have previously seen other people handling different machines in the shop. For this assignment I wanted to challenge myself to try some of them and get more comfortable with them. The idea for my flashlight occurred during a presentation in the applications class when I noticed an image of a desk-lamp on a random slide. I quickly drew a sketch of what I imagined my flashlight to look like.

This was the drawing I made. Basically, I was thinking about creating a small box for the battery-case to fit into. On top of the case would be two additional squares of wood that would be connected with hinges, so that you could adjust the light to go in different directions and use the light as a table lamp.

On monday I collected some wood from “Metropolitan Lumber and Hardware”. This was my first real encounter with a system other than the metric system. Basically, I had no idea what sizes of wood I ordered or how it was cut – but it worked. When getting back to ITP I used the vertical panel cutter to cut my wood panels into more appropriate dimensions.

Although I consider this class to be a lot of manual work I decided to use the laser cutter to create the bottom box functioning as the container of the battery pack. So, I created 4 equally sized squares 4.5 inches by 5 inches. Two of them were considered to be the top and bottom of the case whereas the other two were the adjustable hinge parts.

I had someone assist me on the template and general setup for the laser-cutter. It was very straightforward and seemed to work well with the dimensions of the wood I had bought. In addition to the four pieces I also cut a small hole into one of the layers to fit a toggle switch for the light.

One thing I realized when gathering the components needed for this assignment was that creating a battery-driven circuit is very different from the breadboard setup that I have become very comfortable with over the past months. Without the Arduino and the breadboard the setup had to be visualized in a completely different way. Also, this was the point where I started to question my initial idea with the hinges. I was worried that attaching hinges to the wood would break it. Also, if I was going to create an adjustable lamp with top layers that could move using hinges – how would I connect the wires going to the LED at the very top of my light? After trying out different setups with the pieces of wood that I had already cut I decided to do a more simple setup. Basically, this would just be a box with open sides. So I starting gluing the pieces together. 

The gluing part went surprisingly well. I was worried that the connecting edges of the wood would be to small and therefore wouldn’t hold. I left the box in press overnight to make sure the glue had enough time to harden.

When picking up the “box” the day after I drilled holes for the LED to go through. My intentions were to attach two or three LED through the panel. I tested the circuit on the breadboard to see if it would work. It did. However, I realized that connecting the different parts to the box, when it had already been assembled was nearly impossible. Connecting the battery and switch was no problem – but connecting the two LED’s to that setup I couldn’t figure without having to take the box apart again

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The setup that I could not sort out from a soldering perspective.

The setup I decided to go with instead.

So instead if two small LED’s I decided to go with a bigger light. When drilling the bigger input for the light I gradually increased the size of the drill – hoping I wouldn’t cause harm to the surrounding wood.

This is what the final result looked like. Although it is far from what I imagined prior to the fabrication process, I learned a lot from it. Aside from having been introduced to several of the machines in the shop, just trying to set up a circuit without a breadboard was an interesting challenge – that forces you to see the circuit from a different perspective. Looking back at the project now I would probably have attached the lights and soldered the circuit before assembling the box. That way I would have more room to navigate and solder.

Questions:

How would I connect two LED’s to this setup? Should I have done it before assembling the box?