Creating Wilf Rigter's ZXKBD v3

[mrtinb]

This weekend has been used to solder a pcb connector on the backside of the keyboard controller, so a RAM expansion can be connected. Before I had to choose between keyboard or 16K RAM. (hard choice)

I had made a custom doublesided board to get the pcb connector. You can see the lanes has holes in them (so this board could be used for prototyping as well, as the minimum order is 10 pieces). When I soldered it all together I realized I has made a major design flaw. If there are holes in the board, a connection is created between top and bottom through the hole. These custom print were now useless.



After thinking forth and back again, I came up with the idea to drill every hole, so the connection was broken. Then the pcb connector was soldered in place, and after a few short circuits late yesterday the keyboard controller worked with 16K RAM expansion. Yahoo!!

[gammaray]

After thinking forth and back again, I came up with the idea to drill every hole, so the connection was broken. Then the pcb connector was soldered in place, and after a few short circuits late yesterday the keyboard controller worked with 16K RAM expansion. Yahoo!!

Good save! I have been looking at this too. Single or double sided. double stack of single sided boards...

[mrtinb]

Now the final stage is to make a case for the keyboard. I can use Tinkercad for the design. Then I can use 123D Make to convert the design into slices of 5 mm HDPE plastic. Both Tinkercad and 123D Make are free to use.

[mrtinb]

Now the design is complete. Here's a paper model of the case, and now it has to be cut out from 5 mm HDPE plastic. Everything seems to fit nicely.

[mrtinb]

This is the assembled keyboard. Some quite rough edges, but now it's finished. And it has a little 3D printed logo: ZXKEYB-MA.

[sirmorris]

That is superb!

[albertusj]

In the schematic is 5,6,7,8 and 0 in R3 and R4?

Also, what does C0, C1, C2, C3 and C4 refer to on the keyboard matrix?

[mrtinb]

I just shorted wires one by one to find the key.

[mrtinb]

If you follow the schematic for joystick you will not get 5, 6, 7, 8 + 0.

This schematic will give you 6, 7, 8, 9, 0.

I would advice just to tap into the keyboard matrix to get any keys you want.

[albertusj]

Aaah, yes. I see now. I tried tapping into the keys directly before but got EMI problems due to the long wires. So I'll need a buffer. Also, I'd like to keep my board neat so a plugin unit seems more elegant. I understand now, C0 - C4 is the columns. Thank you for the suggestions.