MAKE#

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:

• Basic knowledge of electronics, including how to prototype with a breadboard, and use a multimeter for continuity testing
• How to sew, and have some knowledge of how to sew circuits with conductive thread
• How to use a laser cutter (you don’t 100% need one, but it’ll make your life a lot easier)

This page is structured like this:

• How to make the fabric grids which the circuits are sewn onto
• General advice on sewing circuits, and the types of components used in Stitch Synth
• Short sections on each module, including a circuit diagram and any other information needed to make it

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.

Tools we’ll be using#

Essentials:

• Scissors
• Hammer (or at least something heavy to apply the metal snaps to the fabric)
• Pliers
• Sewing needles and pins

Nice-to-haves:

• Laser cutter - for cutting the fabric grids. A vinyl cutter might also work (but I haven’t tried this), or you can cut them by hand
• Soldering iron - for soldering a few wires to the jack in the Amp module. You could get away with sewing this into the circuit with conductive thread, but it’ll make a less reliable connection
• Embroidery machine - for the Maryam module. You can also sew this one by hand, but using an embroidery machine is quicker (and fun!).

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#

• Fabric, around 80cm x 60cm in total. I used a mix of fake leather in different colours, and a rubber coated synthetic fabric, but feel free to try different fabrics (or different materials entirely!).
• Needles: try and get a selection of needles of different sizes. You’ll need one or two embroidery needles with a large eye (the hole where the thread goes through), and some sewing needles that also have a decent sized eye, as conductive thread can be quite thick and wiry.
• Threads, in a range of colours that match your fabrics
• Fabric scissors
• Metal press-on snaps
• A ruler (and maybe a rotary cutter) if cutting fabric grids by hand

Electronics things#

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

• Capacitors: 1 x 220μF, 1 x 10μF, 3 x 0.1μF, 1 x 2.2nF (similar values should work fine too)
• Resistors: 3 x 100kΩ, 1 x 10kΩ (or small strips of high resistivity fabric, if you can get it)
• CD40106BE logic IC
• CD4046 logic IC
• LM386 preamplifier IC
• CD4069 logic IC
• IC sockets: 2 x 14 pin, 1 x 16 pin, 1 x 8 pin
• 2 diodes
• 9V battery clip
• 9V battery (get a few!)
• 3.5mm jack socket
• About 15cm of stranded wire + three pieces of heat shrink to fit
• Solder

For prototyping you should also have:

• Alligator clips
• Breadboard and jumper cables

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.

• Stainless steel conductive thread: used for all the main circuitry (where you would use wires ). Substitute any conductive thread / fabric here, as long as it has relatively low resistance (approx 100 Ohms / meter or lower is fine)

• Linen/steel blend conductive thread: used onlly in the Maryam module. Any conductive thread will do here, I just wanted to use this one because it’s white, which made a change from the usual grey colour :)

• Conductive yarn: this is a stretchy knit yarn that has a mix of conductive and non-conductive fibers - see the Anni section for an explanation of why this quality is important, and how to make your own if needed.

• Eeontex resistive fabric: this is a black fabric that has a relatively high resistance. It’s now unfortunately very difficult to find.

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#

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#

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:

• Black rubber coated fabric. Laser settings: Speed 100, Power 40
• Green fake leather / imitation Alcantara: Speed 200, Power 30 (short lines) / 50 (long lines)
• Blue imitation Alcantara: Speed 200, Power 30 (short lines) / 40 (long lines)

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:

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:

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 the circuit traces#

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

• Sew around the relevant IC leg with conductive thread
• Use regular thread to sew over the conductive stitches, to secure the IC leg and also insulate it (see bottom left section of the image above)
• Use regular thread to stitch the conductive thread to the fabric grid.

Checking connections#

The main things that can go wrong here are:

• Short circuits: because we’re using uninsulated conductive thread, stray threads touching each other by accident can create short-circuits, i.e. the electricity doesn’t go where it’s supposed to go, and this means your circuit won’t work properly.
• Loose connections: make sure that you sew tightly around the legs of each component, to make a good electrical connection

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!

• Cut a piece of fabric that’s the same length as your 9V battery, and wide enough to cover the top and sides of the battery- a stretchy material works well here, as you can make it super tight so that the battery holds in securely.
• Stitch the fabric onto the grid to make a little pocket for the battery.
• Sew power, ground and signal traces with conductive thread
• Sew the battery wires down, connect them to power and ground traces

Amp#

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.

• Sew the circuit as in the diagram, except for the jack
• Cut 3 5cm (ish) pieces of stranded wire, strip both ends, and solder one end of each to the terminals on the jack socket. I used a jack socket with three terminals (left, right, ground) - you’ll need to figure out which is which for the one you’re using.
• Once soldered, slide some heat shrink onto each wire and heat it with a heat gun or lighter until it shrinks. This is to protect the wires from short-circuiting
• Use a pliers to twist the free ends of the wire and sew them as in the schematic above (ground = black, left/right = blue)

Volume#

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#

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#

Minimal sewing for this module!

• 15mm wide strips of fabric are woven into a fabric grid.
• Two 15mm wide strips of conductive fabric (Eeontex piezoresistive) are placed on either side.
• Sew conductive thread traces from the snaps to either side of the resistive fabric.

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

Maryam#

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 conductive thread used here is a linen/steel mix that looks white, but you could use any conductive thread.
• The conductive thread is used as the bottom thread in the embroidery machine, because using it as the top thread results in serious tangles. This means you need to put the fabric in the embroidery hoop bottom-side up, as we still need the conductive thread to be on the top of the module.
• I did some experiments and adjusted the machine tension until I got clean, neat stitches that weren’t too loose on either the top or bottom of the fabric.

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:

• Placed a larger piece of fabric in the embroidery hoop
• Embroidered hte design (14cm x 14cm)
• Removed from fabric from the hoop, and used a ruler and scissors to cut out a 15cm x 30cm rectangle
• Hand sewed a line of stitches from one side of the pattern to the other end of the rectangle, and applied snaps.

Daphne#

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

• I hand cut some 3mm wide strips of Eeontex resistive fabric, but you could also laser cut this
• Longer and shorter strips are woven into the grid as shown in the diagram
• A couple of lines of conductive thread are added to connect everything together

Delia#

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#

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:

• Cut out a 30cm x 30cm square of fabric
• Get your conductive yarn, unroll a big length of it (I’d say around 1m but I didn’t do this bit particularly precisely), and arrange it roughly into the pattern in the image above. Cut the yarn and set it aside for now

• Cut slits in your fabric as per the circuit diagram
• Get some 3mm wide strips of fabric (I had laser cut these) and weave them through the holes to form little loops on the top side of the fabric
• Thread the conductive yarn through the loops
• Arrange the conductive yarn into the Anni Albers inspired pattern in the middle of the fabric. It’s a good idea to test the module at this point (by connecting it to the Daphne module, or a breadboard prototype, with alligator clips)

• To keep the pattern in place, use regular (i.e. non-conductive) thread to lookely stitch down each of the points where the yarns cross.
• Sew the remaining conductive traces, and apply the snaps

Hedy#

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

Files and materials#

• Grids: a zip file containing templates for fabric grids in .ai, .dxf and .pdf format (includes a bonus grid that I planned to use to make a sequencer, but didn’t have time, plus templates for fabric strips used in the Anni and Ada modules)
• Schematics: a pdf file of all the circuit schematics, so you can see them a bit clearer than they appear on this page
• component symbols: an Illustrator file containing the custom symbols I made to represent the components, in case you’d like to use them
• Maryam: a zip file containing .ai file for the Maryam module pattern, and embroidery machine files that will work on a Janome machine. Or download the Hilbert2D Grasshopper definition from Morphocode

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:

• Ordered entirely the wrong kind of IC for a Stitch Synth module because it had one additional letter in its name - always double check the details!

• Ordered 50 of a component instead of 5, because it wasn’t clear that putting ‘one’ component in my shopping basket meant ‘one set of 10’ - watch out for this!

• Don’t buy surface mount (SMD) components by mistake- these are smaller components that don’t have the ‘legs’ we need to sew the components into the circuit. If there’s no picture with the product listing, look for the words ‘through hole’ or ‘DIP’ in the description.

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:#

• Adafruit are probably the biggest supplier for e-textiles materials, like conductive thread. But unless you’re in the US, you’re going to pay a lot for shipping (and probably have to pay import taxes) if you order from them. Instead, check their list of distributors (there are many) and order from a company closer to you.

• I personally order conductive materials from Kitronik, Pimoroni and sometimes Cool Components, all of which stock a decent range of e-textiles materials. They’re all located in the UK, which is handy enough for me as I’m based in Ireland / the Netherlands.

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