Finnbarr Hamill
Project Preface
One of my strengths with design and engineering would be my technological research and good project planning. I enjoy making my projects technically advanced as well as incorporating good material design and looking into specific design aspects. An area of growth would be working with metal in cleaner ways, especially when incorporating multiple categories of materials together.
Good reflection is consistently documenting and photographing every aspect of your build and design process, with a concise summary for the reader to have context as to what led to the given choices. Specifically, any major changes to amplifier design should have reasons listed for what wasn't working or liked about the prior design. Having a clean site layout also helps to keep the reflection and documentation from seeming too cluttered.
First Milled Circuit
Shown here is the design that my partner, Kate, and I made. It is for a tri-LED circuit with all 3 of the lights wired in parallel. We worked with Autodesk Eagle and Bantam Tools milling machines to cut out a physical rendition of this board. This brief intro to circuit-milling is great because it lets us have more ability to customise the layout of the circuit we will use in our amplifiers as well as the shape. All of our components were installed cleanly and resulted in a solid introduction to designing a circuit board around your circuit and not the other way around.
Intro to Digital Joinery
This is my (and Kate's) first experience with digital joinery, as I had never properly learned how to put materials together without glue or screws. It is somewhat hard to make an advanced design with more notches, but can still be very useful for areas that need to sit flush, and require little to no physical work thanks to the laser cutter. Occasionally the laser cutter misses a small edge, but remains a very viable option for speaker enclosures due to its perfect fit.
Breadboarded Circuit
This initial circuit is very cluttered, but produces decent sound from 2 attached speakers through a 12V input, and has a few key components. There is the microcontroller which handles most of the microvoltage and music input, as well as capacitors for handling unwanted fluctuations in current, and resistors for blocking unnecessary frequencies (higher and lower than we can hear or the speakers can produce). There is also an LED to easily check that the circuit is working (it isn't plugged in on the attached photo).
My Design Choice
The design that I chose to start developing is 2 separate hexagonal* enclosures, that go deep and are designed to fit on a desk providing binaural sound. They will be supported on small stands, and have an external amplifier with a volume dial and bluetooth module. I chose this design because its able to reproduce balanced audio without taking up a boxy shape, able to have an enclosure that extends rearwards and have ports on the rear end of each enclosure. Clip-on mesh attachments to the front of each enclosure will also be developed.
*May use deep rectangular or cylindrical enclosures instead of hexagons due to audio quality or difficulty in designing.
Enclosure Ideas 1-4
(From top left clockwise) Wide soundbar set into ski, Hexagonal duel sided speaker, Upwards firing desk speaker, Pill shaped speaker
Enclosure Ideas 5-8
(From top left clockwise) Dual up-firing speakers w/ external amp, Up-firing single hexagonal speaker, Dual tower speakers w/ external amp, Dual spherical desk speakers w/ external amp
Enclosure Ideas 9-10
(From top left clockwise) Single up-angled speaker w/ different speakers, Dual hexagonal desk speakers w/ external amp
3D Rhino Speaker Design
Shown to the left is the design of my speakers completed and exploded in Rhino. It demonstrates the digital and electronic side of the class, showcasing the specific design elements and nuances details, as well as exact dimensions. The ports on the rear of the enclosures and data/power ports on the rear of the amplifier enclosure are not displayed at this angle.
Eagle Circuit Schematic
Displayed above is the raw electric circuit map. It displays the different parts of the circuit, and the right wiring between each component. It is a conceptual map that can be then applied to a board design.
Eagle Board Schematic
Displayed above is the design of the circuit board that will be cut. It has the same electrical paths between components as shown in the photo to the above left, however it has been cleaned up and organised to fit onto a small circuit board in a logical way. The red lines are the electrical pathways, or traces, that will be cut into the circuit board from a milling machine.
Cardboard Prototype
Shown above is a rough physical prototype of a singular speaker enclosure, 1 of 2. It is made of cardstock cut to scale and to the approximate final design. The purpose of the prototype is to get a sense of how large your enclosure(s) will be and adjust sizing or features accordingly.
Completed Circuit
Shown to the left is the image of my completed circuit board, having been milled, parts and wires attached, and finally soldiered. The large board hold the majority of the circuitry for controlling the audio, however the bluetooth module is shown on a separate board attached left of the main board. Something particularly challenging for me was sorting out an issue that caused a rapid clicking sound in the speakers, ultimately due to a small 1 uf capacitor being placed backwards. Something I learned was how to design the entire board around your physical constraints and how the most efficient means of creating a board work. Having various components that should be close to each other in an ergonomic setup is a crucial part of designing the board, making soldiering far easier.
First Cuts
The image attached to the left is showing all of the MDF pieces cut to size as well as sanded to fit hexagonally flush against each other. Having to apply a bevel was difficult, but will make a far prettier final design. Currently I have all of the necessary pieces cut for both speaker enclosures. I still need to glue my pieces together correctly as well as cut and glue the enclosure for the circuit board and volume control. If I have time at the end of completing aforementioned tasks, I will devise away to magnetically attach speaker mesh that can be removable to the front of each speaker enclosure.
Completion + Reflection
I was able to finish the amplifier project in time for the final class. I think that the speakers turned out quite well, and they sound great. I added a better power switch to the amplifier and rounded the front edges of the enclosures to yield a more fluid look. I'm most satisfied with the shaping and ability to fit into many desk setups. I like the rigid lines and geometric style. If I was to start over, I would try to account for design tolerances when using precision machines better, as even the small amount of material lost my laser cutting is enough to warrant a long time sanding the enclosures back down to shape.
The most important takeaway for me from this project is to set realistic expectations of yourself. Small errors always happen in designs, and there is no way to foolproof a project from the unexpected.
