MAKE#

schematics gif

Before you start#

This is how to make Stitch Synth! With 10 modules, each with its own circuit, and mostly hand-sewn, it took me about 2.5 months to design, and two (very long) weeks to make the final version. If you have zero experience with both electronics and e-textiles, this might not be the project for you - at the end of this page I’ll link to a few starter projects that’ll get you going.

What you need to know#

For now, I’m assuming you know:

This page is structured like this:

I highly recommend prototyping modules that have an IC in them on a breadboard first - debugging an e-textile circuit is much easier if you’ve made it a few times on a breadboard and really undestand how it works.

breadboard prototype

Tools we’ll be using#

Essentials:

Nice-to-haves:

Things you’ll need (aka bill of materials)#

If you’re like me, looking at a long list of materials needed for a project often makes you sigh and wonder if it’s worth the hassle of trying to find all those things. So I’ve split this list into categories and had added a few links. Also, if you’ve never attempted to buy components from an electronics website before and don’t know where to start, I’ve compiled some advice for you at the end of this page.

Textile things#

Electronics things#

Word to the wise: get a couple of extras of each component, in case you break / fry / accidentally step on one!

For prototyping you should also have:

E-textile things#

I’ve used a range of conductive threads and fabrics, but don’t feel that you have to use the exact things as me - depending on where you are, you’ll have access to different materials, and lots of different things will work. And if can’t get your hands on any of the standard kinds of conductive textiles, try Becky Stern’s method of bringing your multimeter to the fabric shop to find metallic materials, or raiding a family member’s embroidery stash like my fellow Fabricademer Teresa van Twuijver. And you can also use thin / flexible wire in place of conductive thread if you like.

To play Stitch Synth you’ll also need external speakers, and possibly a 3.5mm auxiliary cable to connect the amplifier jack to a speaker.

Making the fabric grids#

fabrics

The basis of each module is a piece of fabric. Most of them have holes laser cut in them, to make sewing the circuits easier.

A template for all of the grids used can be found at the end of this page. You can use this for laser cutting, or to print out templates and cut the fabric by hand.

Laser cut grids#

grids

I designed these grids in Adobe Illustrator and used a laser cutter to cut them out. Small grids are 15cm x 15cm, and large ones are 15cm x 30cm.

Laser cutting

I used three different fabrics:

Corner power was set at 20 for all of the above, and I also cut several 3mm and 15mm strips of each fabric, used in the Anni, Daphne and Ada modules.

Hand cutting#

The pink and purple fake leather I bought turned out to be unsuitable for laser cutting, as we did a flame test - burning a little bit of the fabric showed blue flames, which means there’s something in there that’s going to release toxic gas if laser cut. However, I still really wanted to use these fabrics, so I hand cut them! If you look closely you can tell that they are not as precisely cut as the laser cut pieces ☉‿⊙

SEWING CIRCUITS#

Although each module has its own circuit, they share a lot of the same techniques and components.

Preparing components for sewing#

First, use pliers to carefully bend the legs of the IC sockets so that they point outwards, like this:

ic prep

Be careful not to be too rough with the pliers, or the legs might break!

And use the pliers again to curl the legs of resistors, diodes, and capacitors so that they look like this:

sewn components

Sewing IC sockets#

For modules with ICs, it’s good practice to use IC sockets, which are kind of like a little exoskeleton for the IC, instead of sewing the ICs directly onto the fabric. Although the ICs we’re using are pretty tough little friends, they can be fried and broken if connected in the wrong way. Using a socket means you can swap out a fried IC without having to re-sew all the connections.

Before sewing any conductive traces, use regular thread to sew the socket securely onto the fabric grid:

sewing ic socket

Sewing the circuit traces#

Once the IC socket is in place, the first things you should sew are the power and ground traces.

circuit stitching

Checking connections#

The main things that can go wrong here are:

Use a multimeter to check the resistance between parts of your circuit! And test as you go along - each time you finish a conductive trace, check it with the multimeter. It’s much easier to do this than to try and figure out why it’s not working when you’ve already sewn everything.

Applying the snaps#

I used press-on snaps to connect the modules together. You could also use sew-on snaps (although they’ll be more time consuming!), conductive velcro, or other kinds of metal / conductive fasteners. What’s important here is that they connect together well - loose or weak connections = poorly functioning circuits. As these are part of the circuits - making electrical connections between the modules, it’s important that they’re securely applied.

Modules#

Here’s some specific information for each module. In the schematics below, the usual electronics convention - red = power (+), black = ground (-) - is used. Other than that, different colours are used to make the circuits easier to understand, and don’t hold any specific meaning.

Power#

The simplest module!

power_schematic

Amp#

amp schematic

The jack socket on the Amplifier module has wires soldered onto it, which are then sewn into the circuit. For an earlier prototype version I sewed the jack socket in place with conductive thread, but wasn’t happy with how secure / reliable it was.

Volume#

volume schematic

The volume module is pretty straight-forward to assemble, but one thing I noticed was that when making sewn connections between conductive thread and the resistive fabric from Eeontex, you need to make sure you’ve sewn several tight stitches, otherwise the connection will be unreliable. Make sure to check continuity with a multimeter.

Wendy#

circuit diagram

The Wendy module is the most complex, which means you should test every trace after you’ve sewn it! the strip of resistive material can be replaced with a 10k resistor if needed.

Ada#

ada schematic

Minimal sewing for this module!

Eeontex is super hard to get a hold of now, so you can substitute other conductive fabrics - they should work just fine.

Maryam#

maryam schematic

This module was created using parametric design (Grasshopper for Rhino), and sewn using an embroidery machine. I’ve documented the process of designing the pattern, and the maths behind it here, and instructions for machine embroidery here

The width of the module is narrower than the embroidery hoop of the machine we have at TextileLab Amsterdam, so here’s what I did:

Daphne#

daphne schematic

This module is a bit of a work in progress - it kind of works but it’s not super reliable!

Delia#

schematic

For this module, follow the general instructions in the ‘sewing circuits’ section, and make sure to test your conductive stitches as you go along!

Anni#

anni schematic

This module was made by hand, but you could also do some of the steps with a laser cutter! The resistivity of the yarn, as well as the spaces between where the yarns cross over in the ‘loopy’ part of the pattern, will affect the tones that the Anni module plays.

I mentioned in the ‘Materials’ section of this page that the yarn you use is important. The Anni module plays tones when you press down on the places where the yarn crosses over itself. This only works because the yarn is mostly made of non-conductive fibers, with a small amount of conductive fibers spun into it. Pressing down on the yarn brings conductive fibers from both sides in contact with each other, allowing electricity to flow, and generating sound. If the yarn was 100% conductive fiber, the sound would play all the time - we don’t want this!

But if you can’t find a yarn like this, don’t worry. You can make your own by getting some regular yarn / wool, and using a sewing needle to thread some conductive thread through it (slightly fiddyly, but it’ll work!). Or if you’re feeling ambitious, you could spin your own yarn out of a mix of threads :)

Anyway, back to the instructions:

anni-process-1

anni process 2

anni process 3

Hedy#

hedy schematic

Follow the general advice in the ‘Sewing Circuits’ section to complete the Hedy module.

Files and materials#

Tips for buying electronic components#

Unless you are buying a pre-packaged kit, buying electronic components can be a bit of a pain. It means scrolling through electronics websites, peering at item listings which often don’t have photos and are a bit unclear. In the past I have:

One useful thing I’ve learned is to check the datasheet of the component. This is a file created by the manufacturer that includes lots of information about the product, and electronics websites usually include a link to the datasheet in a product’s listing.

Where to buy?#

There are many different options for purchasing electronics, but here’s my advice.

E-textiles:#

General electronics#

All of the websites I’ve listed above are aimed at ‘makers’, hobbyists, and that sort of crowd, so they sell a lot of kits and a more limited range of individual components. They generally don’t sell the IC chips you’ll need to make Stitch Synth, for example. For that, you need to go for bigger electronics companies such as RS Components, Farnell, or Mouser, or Conrad. None of those companies have particularly easy to navigate search functions, and I’m not particularly endorsing any one of them, but they’ll have what you need.

via GIPHY