Appendix: Answers and Additional Information

This chapter has useful links for your wearable practice, as well as lists some of the suppliers that I would recommend. There are also the answers to the review questions that have been asked throughout the book.

In this chapter, we provide information on the following topics:

  • Useful links
  • Suppliers
  • Answers to chapter questions

Useful links

The links are for online services and tools that can help with your wearable designs:

Also, as a reminder, the tools that I use are mostly all Engineer tools. My preferred soldering iron and other electronics items are Miniware. For sewing supplies, I usually choose Gütermann or Prym items.

Suppliers

The suppliers listed are suppliers I have personally purchased from in the past and have had good experiences with.

US-based suppliers

There are many suppliers in the US that provide components – however, these are ones that I have experience with:

UK- and Europe-based suppliers

These are suppliers I have purchased from in the past and have had a good experience with:

  • https://www.tinkertailor.tech/: This is new to the scene but is the place to go for all conductive materials and all wearable items, from the electronics to the sewing items needed too. All wearable-focused.
  • https://proto-pic.co.uk/: A great site where I got a lot of my first ever components.
  • https://kitronik.co.uk/: They do a lot of school projects and have kits, as well as inexpensive wearable items. They also have a lot of supplies for laser cutters and prototyping.
  • https://coolcomponents.co.uk/: Another good supplier that I’ve placed many orders with. Often, they have items that are out of stock elsewhere.
  • https://thepihut.com/: I’ve always had super quick delivery and good prices from here. I realize it’s called PiHut and we didn’t cover any of the Pi technology, but they have a range of wearables, circuit boards, sensors, and outputs.
  • https://www.bitsbox.co.uk/: This is a good site for general hardware that you might need.
  • https://uk.farnell.com/: Farnell has everything you could ever need, but it can be difficult to find through their search, as there is so much choice.

Answers to chapter questions

Throughout the book you have been challenged with review questions – here are answers to the questions.

Chapter 1

  1. Sometimes, they are defined by augmenting people in some way, such as memory, communication, or in a physical sense.
  2. Typically, wearables have embedded electronics, a power source, and inputs/outputs of some description.
  3. Some exciting intersections exist between wearables and science, fashion, medical, and art. Take inspiration from other fields or plan projects with others who are involved in these areas for interesting and inspired results.
  4. Informed wearables are wearables that consider and focus on uses that will improve someone’s life or help them in some way. They can be designed with the thoughts and feelings of people to understand an issue better.
  5. Wearables can be made for the upper body or lower body and be head-mounted, held, or worn on the wrist.
  6. Ethical considerations when designing wearables include data security, what data we are recording, and privacy. When testing our prototypes, we need to be sure to provide information about what we are doing and get consent.
  7. You should have some sketches and planning for some future projects!

Chapter 2

  1. Swapping out the resistors resists the current and alters the amount of electricity going to that component. It will make our light brighter if we reduce the resistance, and if we add a higher resistance, it will make our light not as bright.
  2. We looked at series and parallel circuits.
  3. A closed circuit has a flow of current through it, so it will work. When it is open, electricity will not flow. This can be an error or done with a switch or button, for example.
  4. A parallel circuit has both ends of the component wired to its power source and ground. These all will work at the same time, as electricity is given to all the parallel components equally.
  5. A soft circuit is a great way to take advantage of fabric and material properties. We can have very flexible circuits that move easily and comfortably compared to rigid breadboards and other structured components.
  6. Conductive materials allow the flow of electricity through them. We can use a multimeter to check whether current is flowing through and whether we can use them in our circuit. We can also check if it is an insulator – so electricity won’t pass. Then, we can use this to cover parts of our wiring.
  7. A practical activity – to create two circuits.
  8. A drawing task to sketch ideas out – I hope you managed it!

Chapter 3

  1. Sensors include temperature and light sensors and accelerometers. There are also speakers, buzzers, and vibration boards.
  2. These kits provide a way to connect a microcontroller easier because most of them have sew tabs and a smaller or flatter shape to integrate into a garment better.
  3. The I/O pins are very important because they mean we can connect the sensors to our circuit through the microcontroller. The number of pins will dictate how many things we can connect to the board. There are digital and analog pins.
  4. The difference between digital and analog pins, is that digital has two states, ON/OFF or 1/0 for example. An analog pin is often used to read sensors so it uses data with values. For example it converts voltage ranges from 0 to 5 volts, to the digital value of 0 to 1023.
  5. We need to check our board is plugged in, that we have selected the correct board from the Tools menu, and that we have the correct Port selected.
  6. The void setup() function is the first code that is executed (one time) if the board is started up or reset. It sets any parameters and initializes what we will be using in our sketch.

Chapter 4

  1. We can test our flex sensor using a multimeter. This will give us a range of values from 0 to the high value. We know it is working because these values will change on the multimeter or in our code through the Serial Monitor window.
  2. The Arduino IDE will give you an error message of “unexpected unqualified id”. The easiest way to fix this is to change your variable name to something else.
  3. This is a good way to see whether our code is working as we expect. We looked at examples to show the position of our accelerometer and the flex sensor output.
  4. We wanted to light the LED with varying intensities, so to do this, we need more control, not just a digital pin of HIGH and LOW. The PWM pin allows us to have a range.
  5. These next questions were for you to sketch out ideas and inspiration.

Chapter 5

  1. We learned about I2C and SPI protocols.
  2. No! It’s a great way to start, with the sensors we buy, but there is a whole world out there in terms of creating sensors, so we really should try that too.
  3. Making our own sensors allows us to create the exact fit, style, and size to suit the wearable we are making.
  4. Libraries add so much to our program. They have pre-written functions that allow us to quickly program the components we want to use.
  5. We can use a digital pin.
  6. Find out the power consumption – is it a 3V or 5V sensor? Also, look for the pinouts – where does ground connect? Find out where the ground, power, and any other connections should be connected.

Chapter 6

  1. The Protocol uses two wires, and it is for serial clock (SCL) and serial data (SDA).
  2. Unplugging the board so you don’t accidentally surge the power.
  3. The line of code turns on pixel number 4 in a string of pixels and turns it blue.
  4. We can add light and vision to our wearables using LEDs, EL wire, NeoPixels, OLED displays, TFT screens, and other screens too.
  5. The switch can be used to select different programs to run on the board.
  6. The additional components are a transistor, a diode, and a resistor.
  7. This was a reflection question.

Chapter 7

  1. We can use any circuit board, but we may need to adapt it to fit the type of wearable we are making. We looked at modifying a circuit board to sew it into our circuit with more ease.
  2. The three main parts of the microcontroller are the processor, memory (volatile, temporarily lost at board reset, and nonvolatile, where the memory stays even when power is off), and I/O peripherals.
  3. Most have Wi-Fi and Bluetooth.
  4. It is a good idea to develop your wearables in parts, component by component, mapping out a circuit on paper, and then building that one part. For example, add the OLED, make sure it works, then move on to adding the second component, and so on. The steps we followed to add our code were the following:
    1. Begin by adding the libraries that the OLED uses at the top of the sketch
    2. Then, work towards the setup() function where what we are using is initialized
    3. Follow with the behavior you want the code to execute
  5. An API allows us to connect to and get data or information from another source. We are using the weather API, for example, to get the current weather information.
  6. We needed the key to connect to our account so the service knows who is accessing this data information. We may have a limited account, for example, with limited calls, so they want to check our rates.
  7. Yes, we can edit variables all at once throughout the code. Right-click and select edit all occurrences from the menu. Now, it will edit them all at the same time.

Chapter 8

  1. The three main areas of prototyping are role, implementation, and look and feel.
  2. These integration prototypes answer several of the design questions. They represent the complete user experience of an artifact. These are time-consuming to build because all the parts should be working or be good representatives of the final prototype.
  3. A low-fidelity prototype might not necessarily look like the final version and will likely use different materials and an altered configuration, but it encourages reflection.
  4. Understanding that different domains will have very different outcomes in terms of the environment we design for, the use, the placement, and so on. There are so many possible variations that designing a wearable for one domain will result in a completely different wearable solution for another.
  5. The best way is to speak with people. Listen to them, their experiences and stories, and they can contribute in a meaningful way.
  6. Fibers and yarns form the structures by being knitted, woven, or non-woven. Fibers can be bonded together using heat or a mechanical or chemical process.
  7. Knit fabrics are made through a machine that forms rows and loops, and then it continues to create rows and loops through the previous row. Woven fabric on a loom has one set of yarns lengthwise and one set crossways. These yarns cross each other. Non-woven fabrics are made when fibers are molded, bonded, or felted. Faux leather is made using this technique.
  8. One way to remember these differences is that knits are made from a single yarn and woven fabrics use multiple yarns (or threads) that cross each other.
  9. Checking the structure can be done by pulling the grin of the fabric and checking the movement in the straight grain, cross-grain, and diagonal bias.

Chapter 9

  1. Other senses discussed include movement, balance, and the position of where our body is and where we are in space.
  2. If we use clothing we already have, we don’t have to create the item to wear first, which can be time-consuming. For rapid prototyping, starting with clothes that we can upcycle is economical and a great solution.
  3. Planning will save you time and help to prevent errors. Planning can help avoid putting components into places that you’ll end up moving because they may stick out too much or be uncomfortable for the wearer.
  4. Plugging in the board, we should always check both the correct board and port have been selected from the Tools menu.
  5. A limitation of the ESP32 S2 chip is there is no Bluetooth.
  6. We would connect to a service such as io.adafruit to create our IoT projects.
  7. A feed is for connecting to our wearable or circuit to read or send data.
  8. We have a dashboard in io.adafruit so we can make the frontend, or the part that someone sees and interacts with. This is where we can display our data from the ESP32 and also use items such as buttons and graphs.

Chapter 10

  1. Soldering will make our wearable more durable and it will last a lot longer than if we left it on a prototyping breadboard.
  2. Some circuits have components too far apart. As we increase the distance of the conductive thread, the resistance also increases. This will prevent electricity from getting through.
  3. A bridged connection means that wires or pins are connected that should not be connected.
  4. We can tell if we have a bridged connection by using a multimeter to check whether there is an open loop (OL) or whether our multimeter makes a sound and registers a connection. If we hear the beep, that means it is bridged.
  5. We can use a solder wick to remove the solder from our wire or connection if we have put too much or need to remove the connection we made.
  6. Some good fabrics for wearables are sturdy fabrics such as denim and felt.
  7. A seam ripper will help us to open up a seam so that we can put electronics in between the fabric. It makes this process easier and less likely to damage the fabric.
  8. Adding IoT to a wearable can increase its usefulness for the wearer if used correctly. We can use IoT to track our data or to interact with the garment.

Chapter 11

  1. It’s important to understand the context and history of your subject area. If you speak with people and they don’t understand the subject, you will likely be wasting their time by not asking the right questions.
  2. Speaking to people is the best way to find out the stories that will ultimately help to create a design that is much more suited to its purpose.
  3. Some of the broad categories that we can consider include educational and research organizations, and researchers, government or policymakers, employers, professional associations and advocacy organizations, standard-setting organizations and organizations that provide technical assistance, companies, and the people directly involved in or affected by the topic.
  4. The three categories of impairment are the following:
    • Permanent (a long-term wheelchair user, for example)
    • Temporary (after accident or illness)
    • Situational (a noisy environment, for example)
  5. Three important aspects to consider are the following:
    • Sensory impairment (loss of vision or hearing)
    • Physical impairment (loss of function in one or more parts of the body)
    • Cognitive (a learning impairment or loss of memory or cognitive function due to old age or conditions such as Alzheimer’s)
  6. With codesign, you are designing with the people who will benefit from the thing that is being designed. This happens all the way through the process so that they are part of it and offer meaningful contributions. Participatory design is about people participating at certain points in the project, but not necessarily the same people, and the amount of contribution will differ.
  7. It’s extremely important to get the prototype to the wearer and create a feedback loop – a way for them to offer you feedback on what you are prototyping.

Chapter 12

  1. If we sew it, there will be an overlap with the ground thread that we’ve just sewn. It will cause a short, so our connections won’t work, and it could damage our components. We need to provide insulation to the conductive thread.
  2. The tack solder is a way to start soldering the board so we get an even and secured solder. We start with soldering one pin on one side of our board and then continue to the opposite side. It’s a way to tack or hold it in place.
  3. Clean and tin your solder iron to protect and extend the life of your tips.
  4. You shouldn’t use pin 2 if you are using the charge board with the QT Py SAMD because it is being used by the board. There is a simple voltage divider on the cathode side of the diode. This is so that the firmware can detect the voltage. If it is higher than 4.3 V, it means you’re likely to be plugged into the USB, allowing charging versus using the battery power. Because of this, you can’t use the A2 pin when using this power board.
  5. strip.fill() fills the NeoPixel strip with one color. First, defined with (0,0,0), are the RGB color values. Secondly, which NeoPixel we want to start from is defined. NeoPixel 0 is the first one, and the third number in strip.fill() , is the NeoPixel position number to finish with.
  6. Case (‘2’) gets called in our code through being sent in the code. We would have to send the 2 value to the switch case when we call the function – in this example, tagActions(‘2’); is how we would call it to then execute the code.

Chapter 13

  1. Setting the road map means that we can plan projects in different ways, but we might start with a component-based plan or a topic-based plan. This helps to set up our plan. Overall, it’s good to consider the domain – for example, forgetfulness, or whatever your topic is – and look at comfort, usability, and style universe.
  2. Iterating the designs is very important because it would be very rare to get a project perfect the first time round. After trying our devices and testing them with people, issues may surface that we can use can improve what we have created.
  3. Non-volatile memory is retained even if the system is powered down.
  4. Positive feedback – and one example of it is an initial sequence of lights to inform the wearer it is working. This is positive feedback from the system to communicate to the person that the system is functioning.
  5. EEPROM is electrically erasable programmable read-only memory.
  6. One note about flash memory is that it has a limited number of cycles on the same flash block for writing, which is around 10,000 write calls. After that, it may start to degrade.
  7. A global object or global variable is declared before setup(), which allows it to be used throughout our program.
  8. An integration prototype will involve role, implementation, and look and feel.
  9. Tin the wire and add solder to tin the legs on your circuit board. Only apply a thin amount. By applying a thin layer of solder to both surfaces we want to join, it helps the solder to flow more easily between them, creating a good connection.

Chapter 14

  1. The benefits of documenting our projects are that we can share them with the community and remember what we did.
  2. Three possible ways to troubleshoot our circuits are to run a blink sketch, to check the board, and check the port. There are a few different responses to this though, including checking you are using a data cable, checking the power, and checking there are no bridged connections.
  3. Other techniques include using 3D printing and laser cutting as tools for prototyping.
  4. This is a reflection question. If there are aspects you’ve enjoyed or have questions about, you can tweet @cmoz.
  5. This was a personal question about your techniques.
  6. This is about your personal thoughts on the future, as a reflection exercise.
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