Soldering and Sewing to Complete Your Project

Learning soldering and sewing techniques to complete a project will provide you with a valuable skillset. This chapter teaches you the basics of soldering to help you to make your circuits more durable and permanent. These skills will help you to take your projects to the next level, from a low-fidelity prototype to a high-fidelity prototype, and ready for wearing.

In this chapter, you will try soldering! We will explore the tools and items we should have, learn some ways to improve our soldering practice, and try a few activities so we can learn this skill. After soldering, we will focus on sewing to make wearables. We will try some activities to put these techniques into practice. Once we have a foundation for soldering, we’ll revisit our project from Chapter 9, Designing and Prototyping Your Own Hyper-Body System. This will provide the practical element as we turn it into a wearable system. Now is the time to take this implementation...

Technical requirements

This chapter is all about learning how to solder and sew your hyper-body wearable from the last chapter. These items are suggested, but we’ll go through how to use them as we work through the chapter. Items can be found on various supplier websites (see https://cpc.farnell.com/, https://www.digikey.co.uk/, https://uk.rs-online.com/web/, https://www.mouser.co.uk/, or https://www.tinkertailor.tech/). You’ll need your prototype from the last chapter and a switch to use as an on/off switch, as well as the following:

• Items for soldering:
  • A soldering iron, stand, and lead-free solder
  • Brass wire sponge solder iron cleaner and tip tinner
  • Wire cutters and tools for soldering
  • Resistors of any value and a protoboard/perfboard
  • Wires: 22 AWG or 24, an LED, a 220 Ohm resistor, and heat shrink tubing
  • Flux, helping hands, a solder mat, and masking tape
• Items for sewing:
  • A sewing needle, needle threader, and thread
  • Fabric, a hoodie, jumper, sweater, or similar...

Soldering

Soldering is a way to join metal (wires, for example) by adding another metal (fusible alloy) that melts (solders) at a lower temperature than the two metal pieces we want to be joined. The solder is the glue holding it together. The purpose is to form a permanent conductive connection between the two connections. It needs to be a good enough connection to survive a pull test. When we’ve soldered our items, we will try the pull test to be sure our connections hold. Welding melts all the metal items together using higher temperatures, and we won’t be doing that with our soldering process. Solder is a mix of tin, lead, and sometimes flux. We can buy lead-free solder, and this is what I would recommend as lead-based solder is too dangerous, not environmentally friendly, and not worth the risk.

You’ll need skill and dexterity to solder. This challenge is something I thoroughly enjoy doing! Practice using old components or buy resistors that are inexpensive...

Sewing

After learning more about soldering and the advantages of soldering our circuits, to allow for durability and reliability, we will look at another making skill: sewing. As mentioned earlier, conductive thread isn't great over long distances due to the resistance. However. we can sew conductive textiles that we have cut in shapes to suit our designs. This allows a larger current to be sent through the material, and we can use this for creativity in our circuits too!

We are going to learn more about sewing through practice. We’ll use our wearable technology project from the hyper-body system we started to prototype in the previous chapter. First, let’s take a look at recommended items for sewing.

Sample items used for sewing

There are a few essential items you need for sewing, and many other optional items too. See what items you already have, and then you can build up slowly all the sewing supplies:

Figure 10.29 – Sewing...

Putting your wearable together

We have our electronic components and we know they are working because we made a low-fidelity prototype with them and the code. Now, we can transfer this prototype to a more stable version by sewing and soldering it in place. Let’s make our wearable in a few steps.

Activity 10.4 – Sewing a pocket for the heat pad

For the heat pad, I’m making a pocket for it to sit in. Because we want the wearer to feel the warmth, I’m using a thin linen fabric. You’ll want to choose a fabric that has stability but that is thin enough to allow the heat to transfer to their back. Measure out the amount of fabric needed and cut wider and longer than the heat pad to allow extra fabric for a folded seam for the edges. Figure 10.31 shows the measuring with the heat pad. Linen can fray, so we want to turn the edge of our fabric inside to create a nice edge that doesn’t come apart:

Figure 10.31 – Measuring...

Summary

This chapter has covered a lot of new techniques and skills. We learned about and practiced soldering, and then we looked at sewing in more detail. These two skills were then used to complete our previous project. The practical nature of the learning should give you a much better understanding of some of the techniques. We completed a wearable that we can use with our family and friends, and we finished an IoT project wearable. This was an exciting chapter, and you will hopefully have time for more practice before jumping into the next chapter.

In the next chapter, we get into the theory behind our informed wearables, and this is by looking at Design Innovation as a process. Another exciting chapter is ahead!

Review questions

1. What advantages are there for soldering a circuit?
2. Why shouldn’t we sew all our circuits?
3. What is a bridged connection?
4. How can we tell whether we have a bridged connection? What tool can we use?
5. Can we remove solder from our wire/connection?
6. What are some good fabrics for making wearables, and why?
7. Why would we use a seam ripper?
8. What is the advantage of using IoT in a wearable?