Intro: Flashy Copper Foil Circuits
Let's face it: copper is pretty. In this Instructable, I'll show you how to use a Silhouette machine (or a similar blade cutter) to create artistic shapes that are also functional circuits. They can be mounted onto decorative paper, as I've done here, or any other non-conductive material.
Like all circuits, these shapes can be powered using a battery, or for more fun, with a microcontroller such as an Arduino. This design includes four independently-controllable LEDs.
Step 1: Supplies and Components
To complete this project, you will need:
- A Silhouette or similar cutter
- Some copper foil tape with conductive adhesive and a sturdy paper backing
- Surface-mount electronic components. This project uses four SMT 1K resistors and four SMT LED's.
- Low-temperature soldering paste. I used SRA brand.
- A soldering iron
- Silhouette brand transfer paper, or other moderately tacky contact paper
- Stiff paper or other material to use as a backing
- A pair of tweezers for handling components
- A toothpick
- A razor blade or hobby knife
- Some kind of power source that can deliver about 5 V. I used an Arduino.
Step 2: Design Your Circuit
You can start with a design and see how it might be made into a circuit, or you can start with a circuit and see how playful you can get with the traces. Either way works, but you're going to have to plan your circuit before you start cutting. How are you going to hook up your wires to the design?
For this project, I found a Moroccan flower design that I liked. The original version is eight solid petals, so it would not work well as a circuit. So, I made modifications to the drawing so that it could be converted into a set of four independent circuits, with each big petal being a circuit.
Making traces: First, I used the Silhouette drawing tools to turn the solid petals into thin outlines. At this point, all eight petals looked like hollow teardrops.
Creating the ground: I added a central ring (B) to the design to serve as the common ground for the four petals.
Creating the four anodes: To control the petals independently, I needed separate contact points for each. So, I separated the left-hand side of each petal from the central ring, and then added small solid circles (A) that I could use to connect each petal to 5V power.
The four small petals (C) are strictly ornamental.
Step 3: Cut the Foil
Once you have your design ready to go, you will need to cut out your circuit.
Copper foil has a nasty tendency to tear! To prevent this and get nice clean cuts, cut out your copper foil tape, smooth it gently to remove any wrinkles, and place a sheet of transfer paper directly onto the foil. You will cut through both the transfer paper and the copper, but not the backing.
Place the foil and transfer paper sandwich in your cutter. On a Silhouette, a blade setting of 2 is just about right. Cut your design out, remove the sandwich from the cutter, and then gently "weed" the unwanted copper off the foil's backing. When you finish, you will want the entire circuit to be sitting on the backing.
The backing is not very sticky, so you may find that individual pieces of the circuit come unstuck and drift out of position. Place them back where they belong. You will probably see an outline of the design on the backing, and you can use that as a guide.
Step 4: Transfer the Copper
Place another, uncut sheet of transfer paper on top of the entire design, rub it to help it stick, and then lift the copper foil off the backing sheet. Make sure all of the parts of the design come along as you lift.
Now, place the design onto your paper, and rub on the copper traces to make them stick firmly. Gently remove both layers of transfer paper. If needed, you can burnish the copper so that it's extra shiny.
Step 5: Cut and Paste
You'll have to make a few more cuts before you can start soldering. This is a lot easier if you make them with a razor blade or hobby knife after the foil is transferred.
First, create some hidden traces underneath the paper, so you can easily hook your design up to a power source. In the first picture, I have cut around the little circles on the left-side of each petal and folded them under to form a via.
Now, cut strips of copper tape and stick them to the back side of the paper. One end of the strip must stick firmly onto the via, so you get good conductivity. (This is why you need tape with conductive adhesive.) The other end can go wherever it will be convenient to attach wires. You don't have to be very artistic on this side of the project, since it will be hidden.
Finally, you need to cut breaks in the traces for your components. Cut the copper trace with two shallow, parallel strokes of your knife, and use the tip to gently pry the little scrap of copper up off the paper. The third picture shows the tip of a petal with a cut in it, ready for an LED.
You may want to practice with some simple foil shapes and components of various sizes. Lots of different components can be added, but they will probably need slightly different gap widths.
Step 6: Solder and Test
Once you have all of your copper in place and ready to go, it's time to start soldering.
Heat up your soldering iron. Then, squirt a little low-temperature soldering paste onto a piece of scrap paper, and use the toothpick to place a tiny dab of solder on each side of one of the gaps you just cut in the copper foil. In the first image, I have put down the solder for the resistor on the left-hand petal.
Now, take your tweezers and put the component down onto the solder. If you're middle-aged like me, you will probably want a magnifier to make sure it's where it should be. Press down gently.
Take your soldering iron and touch the tip to the copper foil near, but not on, one of the solder dabs. As the soldering paste heats up, it will change from dull matte gray to shiny silver. When this happens, immediately remove the soldering iron so you do not scorch the paper. Repeat the process on the other side of the component to finish soldering it in place.
If you like, you can turn the piece upside down and shake it to make sure the component is properly adhered. If you do this, shake it over something that will make it easy to find that tiny little LED if it wasn't stuck on as well as you thought. A dark cloth works well.
Once you have completed each circuit, you should test it to make sure it works. In each petal, I had six possible points of failure: the two tape connections plus the four solder joints. You might find it helpful to test parts of the circuit with a multimeter, or just with a couple of wires (5V and ground) to narrow down any problem areas.
Step 7: And You're Done!
Here's the finished project: a copper flower with four independently-controllable LEDs. The four alligator clips on the right each power one petal. This means you can use an Arduino to create light animations or other effects.
If you just want the LEDs to glow, you can simply hook up the four petal traces on the right to a common power source.
Hope you've enjoyed! If you want to chat, I can be reached at firstname.lastname@example.org. Thanks also to the Tech Valley Center of Gravity, my local Makerspace, for holding a fun Silhouette Build Night and inspiring this project.