Week 2 - Making a speaker
Electromagnet coil speaker
Last updated
Electromagnet coil speaker
Last updated
In this week's assignment, we were assigned in pairs to produce a working speaker. I collaborated with Daniël van Kesteren for this assignment.
The following instructions are paraphrased from Daniël's page.
The first step was to make an amplifier. Components for this were provided to us by the minor. These were: a circuit board, one crocodile clip, four wires with male and female sides, one (...), five wire connectors and an unconnected auxiliary jack. To assemble the amplifier, use the following steps:
Using the soldering iron, solder the (...) to the circuit board. Make sure it's soldered at the side with the positive and negative side on the circuit board.
Solder the 5 connecting points to the other side of the circuit board.
Use scissors to cut the crocodile clip in two and strip both cut sides of the wire so that the fibers are exposed.
Screw the fibers of the exposed wire into the (...) that is soldered to the circuit board.
Cut the male parts of the four wires and strip them the same as the crocodile clip.
Connect the female parts of two of these wires to the circuit board (audio in + and audio in -).
Solder the stripped male parts to the two poles of the auxiliary jack. The positive pole is the short one!
Connect the female parts of the other two wires to the circuit board as well (Ground and 2-5VDC). Ground is the positive one.
You know have a working amplifier! You can check with the Multimeter if everything is connected properly.
With the amplifier working as desired, it was time to design the coil. Thijs and I wanted to work with the vinyl cutter to make our coil. We had chosen to work with copper foil to make our coil, because we had worked with this material before during the making of the circuits in Part I. We already knew this material was conductive and thus could be used in the making of a coil. Thijs used his knowledge with Adobe Illustrator to design a coil with a relatively simple, yet appealing design:
This design could then be uploaded to the vinyl cutter that is located in the Maker's Lab. There are a couple of settings that need to be set correctly in order for the vinyl cutter to work properly:
You need to insert the green knife into the machine. This one is meant for copper paper. The white one is meant for normal paper.
The cutting speed needs to be set to 80 in/s.
The pressure of the knife needs to be set to 6
You need to insert the material (the copper foil) so that both scanners of the vinyl cutter are covered. The vinyl cutter will then scan your material so it will know the boundaries of where it can cut. Once that is done, you can open CutStudio and import the Illustrator file. Then press the R button in the top right corner. Then you need to go to file -> cutting setup -> property -> get from machine, and press OK twice. The program now has the same settings you put in the vinyl cutter. Press Origin on the vinyl cutter so that the knife will move to its starting position. You can now press Cutting to start the cut.
Unfortunately our design was flawed. There was not enough space in between the different coil windings. This caused the knife to have to cut lines that are very close to each other, which in turn caused the copper foil to unstick from it's sticking layer, which ruined to coil, as seen below:
We tried to increase the space in between the windings, but it was still not enough to make the copper foil stick to the sticker layer. Because of time issues, we decided to abandon the vinyl cutter and think of another way to make a coil. During brainstorming, Loes came to us with a great idea for a coil. It consisted of a piece of denim that is nailed on a piece of wood (I used twelve nails. They are nailed in a circular pattern). You then use copper wire to wind around the nails in the pattern shown below:
Once you finished winding the coil, you sew the twelve nodes of the coil to the denim so you can remove the nails. It's quite a simple design but it looks really cool (and Loes promised extra credit if we used it :D). The two ends of the copper wire are meant to serve as the positive and negative connection (it doesn't matter which one is which).
When we tested our speaker, a very dim sound could be heard. When we played a song with a lot of bass, the sound was very distorted. When we played a calm song, the quality exceeded our expectations.
During this week I learned about electrical circuits. I learned how to measure different variables of the circuit, like current, voltage and resistance. Additionaly I've learned about the vinyl cutter. In my opinion, that is a lot. I am really interested in electronics, and I thought it was cool to learn more about it in a step-by-step approach. When I heard about the assignment of making a speaker, I had a lot of ideas. Unfortunately, these ideas didn't work out. I wanted to make a pattern and cut it out with the vinyl cutter from a piece of copper foil. Because of the fragility of the material, I was unable to cut my design out. So Daniël and I had to get creative and make something else. That's how we created the new coil design. The bottom line is that you always have to be creative when things don't work out the way you intended it.
