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--- jansonntag:attempt4 [2021/03/24 17:44]
jan
+++ jansonntag:attempt4 [2021/03/25 17:56] (current)
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 I removed the process of making an average just for testing right now. With the new LDC, I also ordered four Cherry MX Blacks (MX1A-11NN) and soldered these onto the test board. I then tested the board. As it seems to me there is a difference if the board lays flat on my table or if I hold it mid-air. But see for yourself:
+^ This one is mid-air  ^ This one is on my table  ^
+|{{:jansonntag:2021-03-24_18-01-36_trim.mp4 | Mid-air}}|{{:jansonntag:2021-03-24_18-01-36_trim_3_.mp4 | On the table}}|
+Yes, there are still a lot of interferences, but nonetheless, I think the result of this first test is really promising. Because of the different behavior when in mid-air or with a surface under it, I will 3d-print a little (and first of all simplistic) case and make some experiments with that. I even think about adding some aluminum foil into that case maybe this will reduce interference as well. Furthermore, I will have to work on the software as well. Right now it's very rough but I also want to implement some kind of smoothing (possibly after I build the case) and I have to work on reading out all four keys at the same time. Therefore I will have to dig deeper into the documentation. My understanding right now is that I need to change some of the MUX settings.
+As a little bonus I tried what happens when I touch the coil with my finger:
+{{ :jansonntag:2021-03-24_18-01-36_trim_2_.mp4 | LDC and fingers}}
+Maybe this has a function for someone as well. Could be useful in some situations, but I don't know. (Free real estate ;-))
+I designed (a bit over an hour) and printed (2:38 h) the case for my test board. It screws together with M4 bolts and threads itself into the plastic. Because I made the holes for the jumper wires a bit too small on the outer edges, so I decided to solder some wires in place. I didn´t do a great job but I works for now and it looks a bit neater on the outside.
+{{ :jansonntag:20210325_183300.jpg?200 |}}
+Fortunately, even the keys fit perfectly the first time. I found this document where everything about the position of holes for the switches and distances between the PCB and the switch itself is described (in inches but fusion converted them perfectly): {{https://datasheet.octopart.com/MX1A-11NW-Cherry-datasheet-34676.pdf|MX Series - Desktop Profile 0.60 Inch Keyswitches}}
+I then soldered and assembled everything and this is what came out:
+{{ :jansonntag:20210325_184242.jpg?200 |}}
+I didn't put in any metallic foil right now. In the first test, it seems the noise/interference is a bit reduced, but the plastic housing really didn't help a lot. When I hold it midair there is still a difference in the readout when I put my finger on the back of the case. Next, I will try to put aluminum foil on the bottom of the case.

FabLab Kamp-Lintfort

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