@@ -114,10 +114,84 @@ A bird view of membrane clamped with the long rectangular frame.
### Magnet-Coil Hexagonal design
After brainstorming for the first design iteration, we decided on using magnet and coil with Sam's idea of a magnet grid. He succesfully got a few plotted out nicely on 25 micron kapton tape.
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<!--need to verify if it is 1/8" magnet and wood... was it plywood?-->
We then lasercutted the outer frame from 1/8" wood to clamp the coil membrane.
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We then lasercutted the magnet grid plate from the same kind of wood.
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Then, 1/8" magnets were placed in the holes from the magnet-grid plate. Each grid has the opposite polarity.
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<!--Just for fun, we placed a MAGNETIC SHEET?????????????? FORGOT NAME OF THE PAPER AND ITS FUNCTION-->
We used a Gaussmeter to check for the magnets polarity.
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Here is the mapped out magnet-grid. Green for positive and black for negative polarity.
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Sam used the water-jet to cut out a steel plate for the ground plate (the base).
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We tried to lasercut some of the materials that Sam provided us. We tried to cut the 1/8" and 1/16" phenolic sheets with the lasercutter using 0.7% speed, 100% power, 400ppi and were not successful, so we decided to just do it on the plastic sheet.
<img src= "img/wireplotting21.jpg" height=400px>
It did not even go through the sheet! Here is a picture of the burned phenolic sheet at different speed level (0.7-1.5%).
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Sam also provided us with a very thin plastic sheet.
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We tested the cutting settings and found that the best values were: 3% speed, 80-85% power, 400 ppi.
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Here are some five shim/spacers we lasercutted from this thin plastic sheet.
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During our design discussing, we did not get that far ahead into thinking about the testing process. We forgot to add clearance for an RCA plug which will be used for sending audio signals to the coil. Hence, we had to separate the magnet-grid plate from the steel plate (We snapped them together beforehand.)
<img src= "img/wireplotting26.jpg" height=400px>
We used the drill to create a bigger hole for the RCA plug. Had to do it for all layers: steel plate, magnet-grid plate, spacers/shims, frame plate.
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Some fine soldering work came next. Had to peel off the insulation layer from the copper wire for soldering. The copper used for plotting was 40 gauge which makes it difficult to connect to the RCA plug. Thus, we stepped up the copper wire by soldering it to a thicker one.
<img src= "img/wireplotting28.jpg" height=400px>
The resulting planar speaker.
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## Testing
It is testing time!
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We tested our first iteration and here are the results:
No spacer/shim. Minimum separation between the coil membrane and the magnets plate. (First Reaction!)
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@@ -128,7 +202,7 @@ With two spacers separation between the coil membrane and the magnets plate.
<img src="img/out_twospacers.mp4" height=400px>
Three spacers separation between the coil membrane and the magnets plate.
Three spacers separation between the coil membrane and the magnets plate. This video also shows some of the layers of this planar speaker.