Cameras and Settings – Nailed to the Sky – Part 2

I’ve dropped my point-and-shoot a number of times. At least I was able to get the grass out of it.

Selecting a camera and settings for Kite Aerial Photography (KAP) can be tricky. There are a few things that we need to get right to get a good image hanging 100-metres up.

But improving your camera and settings knowledge for KAP will also lift your day to day photography. Get awesome shots all year round!

This is Part 2 of a series on Kite Aerial Photography. Check out Part 1 here, which covers the basics.

Camera selection

The camera I use for KAP is a Canon PowerShot A590 IS, from back in 2008. You can get a similar one on ebay for less than AUD$50.

Here are some of the features to look out for when purchasing a camera.

Megapixels

The maximum possible number of pixels captured by a digital camera sensor is often measured in megapixels, abbreviated to MP. My decade-old PowerShot has an 8 MP camera. By comparison, the iPhone 11 has a 12 MP camera. Well, it actually has three, but it’s also close to AUD$2000.

1 MP is a million pixels, so 8 MP usually equates to a photo with the dimensions 3264 x 2448 pixels. This is close to a 4K image, which is 3840 x 2,160 pixels.

I found that 8 MP is plenty for my use, but newer cameras have more, so grab one if you can – it can’t hurt.

Image stabilisation

My camera also has image stabilisation (IS), which is very handy for KAP. IS was designed to remove the blur caused by shaky hands. It works just as a well to dampen out some of the movement effects whilst tethered to a kite!

Mechanical image stabilisation is done by commecting small servos to the camera sensor. These move the sensor in the opposite direction of the overall camera during the split second the camera shutter is open. This means that whilst the camera may be moving during the shutter opening, the sensor is not, helping you get a better shot. It’s not perfect, but it helps. Image stabilisation can also be done by the camera software, if the servo method is not used.

Optical zoom

Most cameras can zoom in an out to make the subject bigger or smaller in the image.  Smartphones often use digital zoom, where software crops down the image that the sensor captures, to create an apparent zoom. This means a loss of sharpness, however, as there are fewer pixels from the camera sensor used in the final image.

Optical zoom is better if you can find it. A physical lens moves back and forth to increase the zoom by bending the light waves before they get to the sensor. In this way the full resolution of the camera sensor can be used. Most point-and-shoot cameras use a combination of optical and digital zoom.

My PowerShot has an optical zoom of 4x, but it can go to 16x with an additional digital zoom. During flight I generally try to keep out of the 4x to 16x range to maintain image quality.

Mechanical damage

Cameras are fragile, that’s just something we have to live with. But some are more fragile than others. I couldn’t find a quantitative measure to rate the protection from fall damage, so I can only provide an simple engineering assessment.

Point-and-shoot cameras seem to be designed to be knocked around a bit. I can imagine dropping a point-and-shoot into a bag after I’m done with it. I wouldn’t do this with a larger SLR or mirrorless camera. These larger cameras have custom fit cases  for their protection.

Being lighter, a point-and-shoot will reach a lower terminal velocity in a long fall, so will be more likely to survive. Moving parts and large glass lenses of larger cameras are also something to avoid in KAP, as they are  points of possible failure.

I’ve dropped my point-and-shoot a number of times. At least I was able to get the grass out of it. Be prepared for a full replacement and budget for it!

Data storage

Lots of storage is important. KAP uses a ‘quantity over quality’ method of photography, so you are going to need to store all those poor quality images as well as that one good one!

I use a 4 GB SD card for my camera. Taking photos at the resolution of 8 MP, this equates to about 1.9 MB per photo, on average. This means I can take just over 2000 photos before having to swap out the memory card.

I’ve never taken more than 1000 in a day, so 4 Gb is plenty. SD cards have much more capacity these days, anyway.

Camera settings

Shortly after my first flight, I decided to learn all the settings on the camera. I had been using the Auto mode, where the camera tries to determine the best settings for each photo, but these calculations meant a delay between pushing the shutter button and the photo actually being taken. With all the movement of the camera this meant the photos were rarely pointing at the right place.

I aimed to use the ‘program’ and ‘manual’ settings for better control and a quicker shutter response.

But first, let’s look at the automatic mode.

Auto mode

In automatic mode the camera will choose most of the settings itself, but the camera will first try to focus the camera on the subject. An infrared light is used to try and determine distance to the subject, and it takes a second or two. This is a poor choice for KAP, as the subject almost always lies at the ‘infinity’, which can be manually locked using the settings below.

My PowerShot also has an Easy mode, where the camera sets all the settings, except the flash.

Program mode

In program mode, you set most options yourself, but the camera will determine shutter speed and the aperture value (more on these later). Here are the main settings in program mode.

Focus – This is where we set the focal distance to be the same as the distance to the subject, so the subject is captured clearly. The actual area ‘in focus’ will actually be a band of space, but the focus setting determines the middle of that band. It ranges from a few feet to ‘infinity’.

When taking photos for KAP most if not all the images will be far enough away to be considered in the ‘infinity’ range, so just set the focus to ‘infinity and leave it there for the whole flight. Be careful, it might reset to the normal setting if you turn the camera off.

ISO speed – This is the camera’s sensitivity to light. A low ISO speed means the camera will be less sensitive to light, great for daytime shots. Raising the ISO is better for nighttime shots or to avoid blurry subjects, but will introduce ‘noise’ into the image, reducing image quality.

You will need to set this on the day of your flight based on the environment you are shooting in. Take a few test shots and choose the best setting for the day.

Dan’s tip #1: If you are flying at dawn or dusk, or in patchy clouds, you may need to bring the camera down to adjust the ISO speed from time to time. Anything that is affecting the environment’s light levels will change the ISO speed you need to maintain a consistent light level in your photos.

White balance – This is a setting that aims to make sure white items in real life actually look white in the photo. This can be affected by different tpyes of light sources, as they each give the environment a different ‘colour temperature’. Our eyes can adjust to different light sources, but cameras cannot, so they have to adjust with the white balance setting. Sometimes the automatic adjustment setting is a bit off, so we have to set the white balance manually.

You can see the effects of the white balance by taking a photo of something white and seeing if it is represented more white or more red in the photo. If these are off, you need to adjust the white balance. Again, this is something to test on the day depending on your environment.

Drive mode – This allows you to put a delay between pressing the shutter and the photo being taken. Normal options are 2 seconds or 10 seconds. This is used if you want to set the camera down and run to be in the photo, if you want to ensure the camera is not moving because you just pushed the shutter button.

Leave it off for KAP flights.

Colours – This is simply changing the colours of the photo, similar to an Instagram filter. Follow your inner-artist!

Flash – The flash will be too far away to have any effect. Leave it off for KAP flights. This also helps conserve the camera battery!

Metering mode – This is how the camera decides on the exposure settings based on the lighting environment. Most of the time the standard setting is fine, as we will be shooting in daylight. The other settings are for shooting bright subjects or non-standard situations where an average of the image brightness won’t do.

Compression – This is how much the camera attempts to reduce the data size of the photo files. More compression means fewer megabytes, but more visual artifacts in the image.

Set this to Superfine, or equivalent, for the best quality photo – you’ve got plenty of storage space.

Recording pixels – This allows you to choose how many megapixels each photo will be. 8 MP for this camera is just the maximum size. We can also choose 5 MP, 3 MP. 2 MP or 0.3 MP.

Set this to maximum to get the most out of your flight.

Manual mode

In manual mode, you can select all the option described above, plus the shutter speed and aperture value.

The shutter looks like this.

The hole in the middle is where the light gets into the camera. The hole opening time and the size are controlled by shutter speed and aperture settings, respectively.

Shutter speed – This is how long the shutter stays open. Faster shutter speeds mean you can capture a fast moving subject, but it gives the camera sensor less time to capture the incoming light. It won’t work in low light situations. Longer shutter speeds are better for low light situation, but moving subjects will be blurry.

Shutter speed is measured in fractions of a second. For example, a shutter speed of 1/60 means that the shutter will open for one-60th of a second. Also, quote marks mean a decimal place, so 0″3 means the shutter is open for 0.3 seconds and 5″ means 5 seconds. Shutter speeds can often go as low as 1/2000 and as high as 15″.

For KAP, we want the shortest shutter speed possible whilst still maintaining the brightness of the image. This will help reduce the blurriness of the images whilst the camera is moving around.

Aperture – This is physically how much the shutter will open when the photo is taken. A lower aperture value makes the shutter open wider, which creates a shallower band of depth that is in focus.

A higher aperture value makes the shutter open only a small amount, bringing the background and foreground into focus at the same time. This will also reduce the amount of light reaching the camera sensor, so it needs to be balanced with the shutter speed and the ISO.

For KAP, a smaller aperture is preferred, so the whole scene is in focus.

The Exposure Triangle

Shutter speed, aperture and ISO are all tied together, as changing each of them will also affect the light level of the image. If you concerned most with depth of field, you will set aperture first and then adjust shutter speed and ISO the maintain an even exposure level.

For KAP, due to all the movement, we usually want to set shutter speed as fast as possible. Then you can set your aperture to get the correct depth of field, and finally adjust the ISO to make sure the final image has enough brightness.

More resources

The above helps draw attention to some of the camera and setting choices we have, but the rabbit hole goes much deeper. Check out these resources to continue your journey.

ExpertPhotography has a great article on shutter speed and all the effects you can get by controlling it.

You can also find great camera setting cheat sheets at trouvaille22 and Katie the Creative Lady.

Building the camera rig

Catch us in the following weeks as we get into how to build a camera rig, or go back and check out our previous post for an introduction to Kite Aerial Photography!

• Part 1 – Introduction
• Part 3 – Rig
• Part 4 – Camera and Control
• Part 5 – Kites and Flying
• Part 6 – Travel with your gear
• Part 7 – Extra Resources

Check out Series 1 of our Professional Development videos for Teachers to dive in to Engineering for Educators.

Enter you email below to get free access to all 9 videos of Series 1 – Nuclear Power Plants Essentials.

Daniel is passionate about sharing his enjoyment and experiences of engineering with everyone, regardless of where they are in the world.  Based in Sydney, Australia, Daniel has over 10 years of engineering experience: on site, in the workshop, and in the lab.  

Engineering All Sorts exists to help you as an educator to become more confident in engineering concepts and thinking, and to help you grow your STEM strengths.

Nailed to the Sky – Aerial Photography Without a Drone – Part 1

Just you and the wind… and some backyard electronics.

Did you know you can take your own photos at 100-metres without a drone?

It’s called Kite Aerial Photography (KAP), and has been around since the 1880’s. Think of it like a serene version of drone photography – just you and the wind…

… and some backyard electronics.

How it works

Task overview:

• Choose a camera
• Mount the camera to a lifting rig
• Install a way to control the camera
• Choose a kite
• Hang the lifting rig on a kite line and fly!
• Get awesome photos!

However, it’s not as easy as it seems.

Choose a camera

You may have to replace it when it hits the dirt.

The camera we choose should produce a good quality image, as there isn’t much point going to all this trouble for blurry photos – I can do that well enough from the ground. Cameras with ‘automatic’ and ‘program’ functions are great. You can either let the camera automatically try and take the best shot, or you can jump in and control some of the settings in prog.

Also, consider the durability of the camera. It’s likely the camera will fall from a very high point, so it must withstand a moderate level of mechanical damage. Similarly, cost is important, as you may have to replace it when it hits the dirt.

Lastly, lots of storage is important. KAP uses a ‘quantity over quality’ method of photography, so you are going to need to store all those poor quality images as well as that one good one!

Dan’s tip #1: Popular camera choices are the simple point-and-shoot digital cameras from the 2000’s. Although now replaced by modern smart phones, they often provided a high quality image, with lots of automatic functions, large storage, and a moderate durability for a low price.

I have seen KAP using large SLR cameras, but this increase in image quality comes at a higher price, especially if it destroyed. SLR cameras are more bulky and more fragile than point-and-shoot cameras, so a larger more stable kite will be needed, along with a large wallet to fund any replacements.

Using a smartphone as a camera is not something I have tried, but it can be done. Whatever your choice, make sure it is compatible with your choice for camera control, as described further down.

Mount the camera to a lifting rig

The lifting rig is a frame that carries the camera and attaches it to the support lines that hang from the main kite line. It often has legs for sitting on the ground, to keep the camera out of the dirt and dew (or depending on where you are, livestock droppings).

The rig can be made from plastic, aluminium, steel or even carbon fibre. Plastic is cheap and light, but fragile. Aluminium is stronger, but a bit heavier. Steel is strong, but heavy, and carbon fibre is light and strong, but expensive.

You can mount the camera a few ways. The simplest is to fix the camera in one position, often pointing down. This will reduce rig weight and cost, but will limit your photos to top-down. It also means you will have to fly directly over your subject, which may not be possible (or legal).

The next level of complexity is a rig where you can manually set the camera angle before each flight. This is achieved by using bolts that you can loosen and tighten to set the frame in the orientation you want. This method offers bit more control, but you will still have to interrupt the flight to make any adjustments.

The highest level of control is a two-servo system, to control the orientation (north-south-east-west), and the pitch angle (up down) of the camera. These are often controlled using radio control, but can be controlled with wires if you can manage the spool the spool of wire. This wire will add weight to the kite line, so be careful!

Install a way to control the camera

When the camera is up in the air, it will need to take photos without anyone to push the button. The shutter can be controlled mechanically or electronically.

Mechanically, a physical button-pusher arm operates the shutter button to take a photo. This can be hooked up to a timer, so the camera takes photos at regular intervals. Otherwise, the arm can be controlled by a servo for remote control.

Some older cameras have a shutter control wire that can be electronically activated, but newer ones often don’t have this function. Instead, electronic camera control must be actuated via the USB port with a special electronic device, such as a CAMremote. These devices can fire the shutter on a timer, but can also be connected up to a radio control receiver or WiFi for full control of the shutter from the ground.

If you want to get control over all the camera functions whilst in the air, devices such as the above can also interface with the camera to change ‘program’ setting such as shutter speed and ISO levels whilst in the air. You may need to install some intermediate software on the camera to get it working, but it’s worth the effort.

Lastly, how do we see what you are taking photos of? Most cameras have a video output plug, such as HDMI or Component, and this can be connected to an audiovisual transmitter for viewing on the ground. Again this uses radio waves, and light-weight versions can be found on hobby websites and in shops. These can be shown on a laptop or other screen.

Dan’s tip #2: Make sure your control radio system and your video radio system operate at different wavelengths. You’ll get some serious interference if they are the same! My set up uses 2.4GHz for control and 5.8GHz for video.

Choose a kite

These kinds of kites will pull hard if they get out of control. Bring a friend. Or maybe two.

A kebab stick and plastic bag kite won’t cut it here. Even simple KAP rigs are too heavy for this kind of kite. We need to start with kites at least a square meter in area.

KAP kites are made out of ‘rip-stop’ nylon sail, fibreglass or carbon fibre rods, and polyester kite line. My main kites is called a Dopero, and it’s 3 metres by 2 metres. It’s big.

Dan’s tip #3: These kinds of kites will pull hard if they get out of control. Bring a friend. Or maybe two. On a test run of one of the above kite I had incorrectly set up the pitch, and I could not get it down myself. The cable was even starting to cut into my gloved hands. It took myself, my dad and my father-in-law hanging on the line to haul it in.

Another common KAP kite a ‘sled’. This kind of kite doesn’t have any rods, so it’s easy to set up and pack away. The force of the wind keeps it open due to its shape. They are renowned for being great in moderate to high wind, and being super-stable – Nailed to the Sky.

But you can use any kite you want as long as it’s strong and stable.

Hang the lifting rig on a kite line and fly!

Getting the kite airborne can be tricky. You want to make sure the kite is stable before you hang the extra rig load on the main line. You also don’t want to drag the rig along the ground as the kite falters or changes direction.

Watch out for trees, as they can create turbulence near ground level, giving your kite instability below the tree line. Once you get above the tree line, the kite may pull much harder and even change direction.

Beware of power lines, telegraph lines, people and buildings. You could seriously hurt yourself or others if you come down on any of these things.

Often, one person will concentrate on flying the kite, whilst another hangs the rig and controls the camera. Once stable flight is achieved its easy to hook your rig lines up to the main line, usually by winding the main line around the aluminium connectors.

For single person operation, you can get a kite stake that to stick into the ground amd tie the kite line onto. You can do this whilst you attach the rig and control the camera. It will only work in super-stable conditions, however, as the stake cannot feed the line in and out to maintain kite altitude.

Dan’s tip #4: Know your flying height limits. In Australia it’s 120m, unless you are near an airport. Are you allowed to fly at this location? Do you need authority to fly?

Let the kite out and try to get some height. Then start taking photos!

Get great photos!

I wish. Ninety-nine times out of a hundred, your photos are going to be blurry, pointing at the sky, or close-up shots of your nostril. Photography doesn’t like movement, and your camera is hanging off a kite!

But it’s worth it for that one great shot.

Catch us in the following weeks as we get into the details of Kite Aerial Photography!

• Part 2 – Kites
• Part 3 – Rig
• Part 4 – Camera and Control
• Part 5 – Kites and Flying
• Part 6 – Travel with your gear
• Part 7 – Extra Resources

Check out Series 1 of our Professional Development videos for Teachers to dive in to Engineering for Educators.

Enter you email below to get free access to all 9 videos of Series 1 – Nuclear Power Plants Essentials.

Daniel is passionate about sharing his enjoyment and experiences of engineering with everyone, regardless of where they are in the world.  Based in Sydney, Australia, Daniel has over 10 years of engineering experience: on site, in the workshop, and in the lab.  

Engineering All Sorts exists to help you as an educator to become more confident in engineering concepts and thinking, and to help you grow your STEM strengths.

4 of the Best Engineering Games – Learn AND Have Fun – Part 2

eeLearn through doing with these great Engineering games from over the last few decades. They are great for passing on to students or just diving in yourself!

This is Part 2 of this series of blog posts. Check out Part 1 here.

Some of these games sparked an interest in Engineering in me. The rest helped me learn during my career. They fostered my passion to create things and taught me about the process of design. They also helped me put new-found knowledge straight into practice – a key tenant of learning.

But my favourite aspect is that these games are deep, full of details and the challenges they pose. Sometimes the learning curve is steep, but these games teach you about the real world.

Take On Mars

Following a short tutorial, the mission goes bad, fast.

Take On Mars is somewhat similar to Kerbal Space Program: you have control of a space program, you can explore the surface of Mars, and you’ll need to take into account real-world issues like wind and darkness. But that’s where the similarity end.

Dan’s tip #3: Take On Mars has some fun elements, but it may only appeal to a certain set of people. The simulation is much more rigorous, and hence the pace can be slow. Play this game if you are happy to wait for a long term payback. I should also mention that the game has a few bugs that will never be resolved, as the developers stopped working on the game some years ago. More on this later.

There are two separate gameplay streams in Take On Mars. In the first, you command a solely-robotic exploration of Mars. Starting out with a few components and a small amount of capital, start by sending basic probes to a few locations on Mars. No moving parts, just a camera and few sensors to take some readings for the mission. The probes can’t even move around on the surface. By successfully completing the mission objectives you earn a few dollars to put toward the next mission.

By choosing a suitable research path, you can discover new parts for use in each mission – robotic frames, better cameras, more advanced sensors, even solar panels so you aren’t relying on batteries. Working constructively in this way, you can complete more complicated missions for more money, feeding your enterprise.

The game locations in Take On Mars are based off real Mars locations, so it wasn’t long before I had a rover crawling around Victoria Crater, analysing soil samples, and trying not to get stuck on a rock. It was pretty enjoyable to design a robot within the limitations of the robotic frame, to complete as many missions as possible in one hit.

But after a while, I wanted to get into the second part of the game – the manned missions. Following a short tutorial, the mission goes bad, fast.

Spoiler Alert regarding the book and movie The Martian by Andy Weir! Skip to the next section if you don’t want to know what happens!

The manned missions were inspired by The Martian by Andy Weir (also very good!). After a spectacular crash on entry to Mars, you find yourself the only survivor of the mission, with only a few minutes of oxygen and no shelter. You have to spend your first minutes carefully digging through the debris to find some more oxygen canisters, a replacement helmet for your leaky, cracked one, and a pop-up emergency tent. Then at least you have some time to figure out what to do next.

The remainder of the game is spent trying to get home in a series of steps, each building on the last. First, collect some food and a communications device. Then find the parts for the modular truck and assemble it. Call for the orbital supply drop, then drive to each location to pick up the resource processing equipment (allowing you to make more supplies!). The first stage finally culminate in a massive, wheeled Mobile Lab that you can use to get to the back-up base and return ship some miles away. Then you can finally get down to growing some potatoes!

The resource fabrication part was quite fun for me. There was something that I enjoyed about collecting and hauling canisters of resources to feed into the fabricator. I could build something from essentially nothing, starting with martian rock and sand, and ending up with more equipment for my mission.

I loved Take On Mars, but it did cause me frustration at times. In the robotic missions, the rover was quite slow. I know the game rover speed was about 100 times faster than actual rover speeds, but it was still slow for me. I’m at a stage of life now where I can’t spend much time playing games, so any time I do spend has to be efficient! I can’t spend twenty minutes driving from one location to another. In the manned missions, the walking speed isn’t much better, especially with the bigger space suits.

I also found the mission screen and organisation of the robotic missions a bit complex. Sometimes it was hard to determine what was part of the current mission, which were the optional parts, and which were from other missions. This often meant more wasted time and limited resources.

Also, the game gets really dark. I’m not talking about dark themes. I’m taking about the sun going down. Don’t make the mistake of landing your robot in the middle of the night – you won’t get anything done. It’s just pitch black. And you can’t recharge your batteries with solar panels if there’s no sun, so the rover will simply grind to a halt. The manned missions have the same darkness problem, but at least the space suit has a passable night-vision function.

Lastly, the game tended to crash a fair bit, and this is what stopped me playing. There was a certain part at the second landing site during the construction of a 3D printer that would not let me pass. I was so close to getting home and the game wouldn’t let me finish! I was pretty disheartened after that.

I highly recommend giving Take On Mars a go, but be prepared for a few hiccups along the way.

Special Mention: Gizmos and Gadgets

It sounds light-hearted, but remaining true to the style of games from this era, it’s actually pretty tough.

I have fond memories of Gizmos and Gadgets, if a little hazy. Published in 1993 by The Learning Company, it’s been a quarter of a century since I last played it. Until today! You can play Gizmos and Gadgets over at Classic Reload! 

The object is to win a bunch of races with road and flying machines you build yourself. To collect the best parts, players must travel through a series of warehouses completing physics puzzles along the way. 

The puzzles are varied across balance, electricity, energy, force, gears, magnetism and machines, and increase in difficulty as you go. I remember wiring up circuits and building gear trains to get past each level.

There is also a challenge mode where you can play against a team of robotic monkeys that steal your parts and generally cause mayhem. It sounds light-hearted, but remaining true to the style of games from this era, it’s actually pretty tough.

The Learning Company also produced a number of other games, my favourites being Operation Neptune and Ancient Empires. Try them out!

Check out Series 1 of our Professional Development videos for Teachers to dive in to Engineering for Educators.

Enter you email below to get free access to all 9 videos of Series 1 – Nuclear Power Plants Essentials.

Daniel is passionate about sharing his enjoyment and experiences of engineering with everyone, regardless of where they are in the world.  Based in Sydney, Australia, Daniel has over 10 years of engineering experience: on site, in the workshop, and in the lab.  

Engineering All Sorts exists to help you as an educator to become more confident in engineering concepts and thinking, and to help you grow your STEM strengths.

3D printing a reusable leather stamp

Predictably, I thought to myself: “I can make that”. This kind of thought is a blessing and a burden, and a recurring theme for me.

A few years ago, after my wallet started to fall apart, I became interested in leather-working. I couldn’t find a new wallet that I liked, and the slimline card wallets I found were too expensive, being only two bits of leather sewn together.

Predictably, I thought to myself: “I can make that”. This kind of thought is a blessing and a burden, and a recurring theme for me. It feels good to make things, but it can eat up my time. Often much more time than I thought it would at the outset. More on the Human Planning Fallacy another day.

Over the years I’ve made a leather key fob, leather travel cord organiser, and a sheath for a blade (an old handheld scythe that I use to cut the grass – but that’s another story). I did make that wallet, too.

But my pieces were looking a bit plain, and I started looking into adding some flourishes, by stamping and embossing the leather with patterns. Here is how I’ve been able to create my own leather stamp with a 3D printer.

Shortcut: You can download the file for your 3D printer below! Just enter your email and we’ll send it to you.

Process

It’s OK, “engineering is an iterative process”.

I designed the stamp on my computer, turning an image file into a 3D printable file, then printed it. More details on each stage below. Overall, the time for each stage was:

• 2 hours – Design
• 1 hour – 3D printing
• 24 hours – Stamping

I also faced a number of challenges that taught me some valuable lessons along the way. Often, they sent me back to the drawing board. It’s OK, “engineering is an iterative process”. These included:

• Licencing of images,
• User interface quirks of software,
• Mirroring the image, and
• Printing small items

Keep an eye out for these below.

Making the stamp

Better to stick to my own intellectual property in this case.

The stamp that I made was 3D printed on an Ultimaker Original, but it took a lot to get to this point. The steps are:

• Convert an image file to vector format – with Inkscape
• Use the vector file to generate a 3D shape – with 123D Design
• Print the stamp – with Cura and an Ultimaker Original

Convert an image file to vector format – with Inkscape

Start with a .png or other image file that you want to turn into a leather stamp. Import the image into Inkscape, which is a free vector editing program. You can use Inkscape to clean up the file and turn it into an .svg file, which is needed for the next step.

Lesson #1: At first, I wanted to create a stamp of an interesting map that I had found, called a Dymaxion Map, or Fuller Projection Map. This map is interesting for a number of reasons, most of all because of it’s low distortion of the land masses. But this map is trademarked by the Buckminster Fuller Institute, and is only available for use through a licencing agreement. Better to stick to my own intellectual property in this case. You can read about the Dymaxion Map over at bfi.org.

A vector file differs from a normal image (or raster) file in the way it stores the shape and colour information of the image. A raster image is a series of pixels, each with their own colour and location. The image looks fine if you are using a normal resolution, but as soon as you try to zoom in the output becomes very blocky.

By contrast, a vector image stores the shape data in the form of a line equation. This way, no matter how far you zoom in, the image will always have smooth edges. This is also a prerequisite for using the image for 3D printing.

Use the ‘Trace Bitmap’ function to convert the raster .png image into a vector format. This algorithm processes the image and makes an approximation of the image in a vector format. You can control how accurate it will be – more accuracy simply results a larger output file.

For us, lower quality is fine, as the final stamp’s resolution will be limited by the 3D printer. I even went so far as to use the ‘Simplify’ function to reduce the complexity of the vector file some more.

Lesson #2: Remember to click on the image in Inkscape to select it, before using the ‘Trace Bitmap’ function. Missing this caused me a fair amount of confusion!

Next, adjust the dimensions of the .svg image to match your intended stamp size. Doing this at a later stage will reduce the quality of the stamp.

Lastly, save the file as an .svg file, ready for the next step.

Using the vector file to generate a 3D shape – with 123D Design

Next, start up 123D Design – a free Autodesk CAD program. Here you can import an .svg file as a sketch.

Firstly, double-check the sketch is the size of your intended stamp. If not, go back and change it in Inkscape, and update the .svg file.

Next, simply extrude the sketch until it is about 4mm thick, which should be plenty for a leather stamp. I also built a backing board around all the pieces for structural strength, and to keep all the little stamp pieces in the right place, about 2.5mm thick.

Lesson #3: When I printed this out the first time and stamped my piece of leather, the image was mirrored on the leather! For the final product I made sure to mirror the shape before printing, so the image was stamped the correct way around.

Lastly, export the file as an .stl file ready for printing.

Create a printable file – with Cura

Cura is the software that comes with an Ultimaker, but any 3D printing software will do the job here. Import the .stl file, and we are ready for the following adjustments.

I used PLA with a 0.1mm layer height and 0.4mm nozzle. My wall thickness was 0.8mm with an infill density of 20%. These are standard printing settings for an Ultimaker of this style.

The only special function that I used was ‘Enable Ironing’, which attempts to smooth out the top layer. This helps remove the printing lines from the finished leather piece.

Lesson #4: Also after the first print. I found that the outline of the text “Engineering” was too thin to be printed. As a result, I went back to 123D Design and filled in the inside of the text with a further extrusion.

The print took about 45 minutes.

Feel free to download a copy of the .stl here. Just enter your email and we’ll send it to you!

Applying the Stamp

The leather I used is approximately 3mm thick and dark brown. I purchased it for about AUD$25 at the The Fabric Store in Sydney. It was about a square meter to start with. I only used a piece about two inches long for this stamp.

To stamp the leather, you’ll need a few things:

• Leather and stamp
• Two pieces of timber
• Two clamps

First of all, soak the leather in water until it is wet through. This helps it to form around the stamp.

Place the stamp face down on the smooth side of the leather, and sandwich this between the two pieces of timber. The timber spreads out the force of the clamps for an even pressure on the stamp.

Lastly, use the two clamps to squeeze it all together, increasing the pressure on each clamp incrementally and alternately to keep the pressure even. Don’t put too much pressure or the stamp will crack – it’s only plastic after all. The stamp should sink into the leather a bit.

You may need more timber and more clamps for larger stamps.

Wait

I left the stamp in the clamps for 24 hours to be sure. You can experiment with shorter times, but I found that only an hour or two is not enough for the imprint to take hold.

Outcome

The stamp could probably do with a bit more cleanup with a small abrasive tool remove any leftover printing debris, but I was pretty happy with the outcome.

I’m already pondering the next design – “I can make that”.

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Daniel is passionate about sharing his enjoyment and experiences of engineering with everyone, regardless of where they are in the world.  Based in Sydney, Australia, Daniel has over 10 years of engineering experience: on site, in the workshop, and in the lab.  

Engineering All Sorts exists to help you as an educator to become more confident in engineering concepts and thinking, and to help you grow your STEM strengths.