Circuit stickers: electronic circuits made of copper tape

Circuit stickers are electronic circuits made of copper tape cut with a vinyl cutter. It’s a very easy and extremely cheap way to create your own circuits. In this blog post you will find the information on how to use this technique.

Idea

The idea to build circuits made with copper tape is not a new one. Some time ago, it became clear you might be able to cut copper tape with a vinyl cutter. The only problem was to find suitable tape. The options available are often very expensive…too expensive to use for classes with 30 students.

Out of frustration I searched other ways. In particular, I wanted to program the paper circuits with an ATTiny. (The ATTiny is a small and cheap programmable chip.) The idea eventually evolved in toa technique for screen printing the circuit traces. You can find worksheets here. Programming is done with blocks (mBlocks) so it’s accessible for everyone.


During the 2016 FabLearn conference, I met Jeannine Huffman and fellow Fablearn Fellow Susan Klimczak. They have been working on this kind of material (ATTiny, paper circuits) for a lot longer and do wonderful things! They were very excited about the ATTiny circuit trace we designed, which I demonstrated to them. During that conversation, we also found that we shared an enthusiasm to find new ways to use programmable and expressive paper circuits with students. We are inspired by the poetic work of Jie Qi.

 

 

Susan started to use the break-out and a few months later I got a tweet saying that she had made the circuit traces by vinylcutting copper tape. What! Wait! She uses this to make small pieces of kinetic ‘art with a message. Crazy! Soldering also proved to be easy to do. What a great idea! She wrote a deliciously detailed blog post on it. (with drawings by Marten!)

Encouraged by Susan’s enthusiastic tweets and even more convinced of the usefulness of her work, I gave the idea another chance. A reasonably priced roll of wide copper tape was found; this blog post is the result.

What do you need?

Making is about using materials. So we need to buy stuff. The key piece of equipment needed for this technique is the vinyl cutter (although you might also be able to cut circuits with a sharp knife). With a vinyl cutter, you can cut a lot more than just circuits. To have an idea and to be able to make it and hold it in your hands is a powerful thing. Come to think of it… there should be a vinyl cutter in every school. Cheap and easy to use. It’s the ideal stepping stone towards digital fabrication! Digital fabrication has so many possible education benefits.

For some easy shopping, I have made a list here.

One-time purchase:
-vinyl cutter (to be sure, order an extra knife)
-ATtiny programer
-tweezers
-power supply (adjustable)
-power jack to crocodile clips adapter
-soldering iron

Consumables:
-copper tape 3mm, 5mm and 100mm wide
-transfer film
-ATtiny
-DIP 8 socket
-SMD LEDS 1206
-solder

Tips en tricks

Creating a circuit takes four steps:
– Drawing of the circuit
– Cutting the design
-Transfer the design and solder the components
– Programming of the ATtiny

Drawing of the circuit

You need a vector drawing program. There are plenty to be found. I use Affinity Designer for the designs and Adobe Illustrator to operate the vinyl cutter. I build the designs from parts and finally unite them into one circuit trace design. Remember to do this, otherwise they will be cut as loose parts.

Cutting the design

Do not draw too many line traces that are too thin while designing your circuit because the design may be cut all the way through. Lines thinner than 1.5 mm are likely to break during cutting. Because we use a 100mm wide roll of copper tape, your design can be up to 200mm (width of our vinyl cutter, Roland Stika SV8 ) and 100mm wide. You always have some loss, so the actual size is a bit smaller.

Transfer the design and solder the components

After weeding – or taking off the extra copper pieces to leave only the copper circuit trace (which is easy to do with tweezers) — transfer the design with transfer tape. You can stick it on plain paper or any smooth surface you like. Soldering is very simple. Put the tip of the soldering iron on the copper tape, wait for a second and apply some solder. To solder the socket or SMD-LED, I place a little puddle of solder at the place where I want the components to go. Then, with the tweezers, I put the socket or SMD-LED in place. Just heat the solder again and everything flows together. Did you make a mistake? Just reheat the puddle and remove the component! The leftover pieces can be used to make a a SMD test strip. Just use strips of copper tape with a gap of 2mm on a piece of paper, then connect the power supply (3V) with crocodile and you’re ready to go. You can test all LEDs before soldering them in place. You can also test them afterwards by keeping the crocodile clips in the right place, powering each component. You can do this without having the ATTiny in the circuit.

Programming the ATtiny

There’s a little learning curve, if you have never programmed anything with the Arduino IDE. The good news: you probably only have to do it once and it is really not that hard. All it takes is time and attention. You can always ask others help you. There’s always someone around with Arduino experience or you can also visit a neighboring Fab Lab, library, or makerspace to find folks that can help.

You can use the Arduino IDE to create programs for your circuit. If your not familiar with Arduino you may use Circuits on Tinkercad. It’s a simulation (with the ATtiny!) and uses blocks programming. It’s really easy. Once you get your simulation to work you can download the program as a Arduino compatible file! Hooray!

To use the ATtiny programmer, follow these directions.

 

 

Why bother?

 

It’s probably not the best way to get started with maker education. But I think it has a lot to offer for a classroom. Here are some reasons I’m enthusiastic about this technique:

Solving problems

As with any design or creation, you have to deal with limits. I think limits really help with the creative process. Here the space for your design is limited.  The ATTiny is very powerful, but it has only a finite number of possibilities. When making my prototypes, I had to solve a lot of little puzzles. How do I get what I want? Thinking, trying, thinking again … That’s a powerful engine to learning. And it gets you focused.

It became once again clear that the level of understanding I get when I make something is really different from when I learn from reading a circuit on paper. When I was designing the circuit (for the charlieplexing) I finally “got” how it works. I thought I had already understood by studying the circuit on paper. Wrong!

High ceiling

Often, you can use this activity in different ways. You can use it to learn a technique, such as learning programming or learning to make an electronic circuit (and to understand it!). But you can also use it creatively and expressively. What could you do with the subject that you teach? Can LEDs indicate the metric rhythm of a poem? Students usually invent unexpected things when they have expressive freedom. There is more on this in this post.

Even though the ATTiny is very small (tiny, duh ..!), it is really powerful! The pins are touch-sensitive. You use all PWM pins (two of which are hardware PWM). With Charlieplexing you can control more than 5 LEDs. In short, there are so many possibilities. At the end of this post there are some helpful resources to give you ideas about the various possibilities of the ATTiny. I don’t include them here for the sake of readability.

Circuit stickers and cardboard are natural partners. An ATTiny, a servo, Make Do and cardboard. Imagine the possibilities!

Iterate

I think this is a very powerful point. Because we use digital manufacturing, you can quickly make your idea into a prototype and have it in hand. You’ll soon find out if your idea works. That’s the fun partl. Your concepts and ideas can be tested in the real world. Did you do something wrong, because it doesn’t it work? Then, you can make changes quickly, redo the circuit and you can have a new prototype in your hands within minutes. This is the major advantage of digital manufacturing. It’s shifted what used to be just making skills to “thinking through making” skills. Paulo Blikstein calls this “The Democratization of Invention”.

That does not mean that maker skills are not important either. But to understand something, the strong iterative character of digital fabrication is of great value.

Affordable

Affordable? Making takes money. That’s just the way it is. What I like here is that you have a working project for about a dollar. Students can take their projects home.  They can reuse the chip, to create a new project for a few cents. I know of few techniques that are so affordable. For around $500 you are all set, including the vinylcutter. Keep in mind you can do so much more with a vinyl cutter.

Low floor

You can already see “the low floor” between the lines. The 2D drawing, programming, the vinyl cutter, it all has very as a low floor. And because it’s cheap, you can repeat it and use it in different ways.

In addition, the #makered community is very open. Help is never far away.

What’s next?

In a tweet, I got the tip to use an ESP8266 module instead of an ATtiny . Somewhat more expensive ($1.75 instead of $0.85) but, much more powerful, more pins and WiFi enabled.

You could also use the micro:bit as a ‘brain,’ using crocodile clips to control your design. However this makes letting students take their design home is a lot more expensive.

Because the circuits bend, Susan suggested making bracelets. You can use a 3V coin cell to power it (and a magnet as the clip for both turning on the circuit and fastening the bracelet). The good thing here is that you your circuit traces can become the design. Imagine beautiful patterns decorated with working LEDs!

I’m thinking of doing something with the ATTiny touch sensitive pins. I just have a feeling there’s a meaningful activity to do. Maybe touching the parts of a cell after which an LED highlights a text that explains its function.

How would you like to use this technique? Let me know. For example, with a tweet using #circuitstickers. At the bottom of this post are some sources full of ideas for further exploration!

As always, comments, additions and improvements, it’s all welcome!

Per-Ivar Kloen

@___pi

I wish to thank Susan and Eva for their help translating the Dutch post. I’m so thankful and a bit blown away by your kindness. 

 

Tutorials on how to make paper circuits.

Detailed post on Charlieplexing.

More High-Low Tech.

A treasure trove of ideas, materials and techniques.

Here you’ll find my designs and used code.