3d printed mitsumi keyboard sheets?

[jrhodes]

Would it be possible to use 3d printing to recreate the mitsumi keyboards mylar sheet?

[+arcadeshopper]

3d printing is plastic.. hard plastic..   Mylar is flexible and the particular keyboard layout has conductive ink on it..  

[JB]

So you could 2D print a replacement, if you had the ability to print with conductive ink.

[Shift838]

could a flexible PCB work?

[+arcadeshopper]

It really want my opinion make a regular pc board with modern switches and be done with it the mylar is the worst idea and has proven to be unreliable over time

Sent from my LM-V600 using Tapatalk

[wierd_w]

There *ARE* soft/rubber-like 3d print filaments.

 

They are hard to work with.

 

See this TPE (Thermoplastic Elastomer) filament.

https://www.amazon.com/eSUN-Elastic-Flexible-Printer-Filament/dp/B01A4WP4AY

 

I would think a better solution would be to print a wholly-new backplane to completely replace the mitsumi keyboard. It should be possible to print channels for wires to be easily tucked into, on a rigid flat sheet of printed plastic that has holes for discrete switches to be mounted on.  Then you just wire-wrap, solder, and tuck.

 

Still.. It MIGHT be possible to print a replacement sheet, it just probably would be far more trouble than it is worth.

[cbmeeks]

I have a mylar membrane for my MSX 2 computer where the conductive ink has literally vanished.

 

I thought about using copper tape and/or silver ink to try and draw it back.

 

But I agree, mylars are the worst things ever (well, flex ribbon cables are bad too).  It would be great to have a new PCB created so we can just use cherry switches.

[AwkwardPotato]

1 hour ago, cbmeeks said:

But I agree, mylars are the worst things ever (well, flex ribbon cables are bad too).  It would be great to have a new PCB created so we can just use cherry switches.

The PCB would be the relatively easy part; the hard part is coming up with new mounting hardware to install the PCB in the case (modern switches are lower profile so the whole board has to be raised up) and finding keycaps that look appropriate in the TI.

[Shift838]

16 hours ago, arcadeshopper said:

It really want my opinion make a regular pc board with modern switches and be done with it the mylar is the worst idea and has proven to be unreliable over time

Sent from my LM-V600 using Tapatalk
 

maybe this will be my next project!

[wierd_w]

I had a radical idea, and did a quick proof of concept test, for diy projects that simply must have conductive membrane.

 

I just took a small square of foil emergency blanket and applied concentrated muriatic acid to it with a cotton swab. I was successfully able to remove the foil backing from the blanket where it was treated. (You need to test which side is exposed foil)

 

The resulting salt in the cotton swab is grey, which is consistent with aluminium foil coating. It should be possible to do chemical film deposition of copper onto that with dilute silver nitrate and copper sulfate solutions (to make solder pads that stick). Painted resist could be used to mark areas to retain metalicity for full acid wash.

 

I wholly recommend a proper pcb for keyboards though. I only mention this as a technical aside for tinkerers to play with.