The Sinclair QL Forum

Pr0f wrote:

Ruptor wrote:

Pr0f wrote:no - it was about an interface board he's made to go into the keyboard tail sockets and has I think a 20 pin connector with an IDC female end on it

Oh! thanks, the PCB plug. Probably Derek would like it but it is too neat & fancy for me.
I don't think a straight one piece PCB would fit a QL because the connectors are offset by the width of a PCB but I guess it could be cut and made in to two PCB plugs.

Hi,

No need, to send your schematic.

I will amend my attempt with the newcswitch.

The switch iscavailable on Farnell:
https://uk.farnell.com/omron/b3fs-4002p ... p/2113269#

Here is the datasheet

That switch requires 150g of force to actuate. The commonest actuation force is 45g, and 65g is considered ‘stiff’...

Hi,

My original idea was to use Cherry switches, but the was a problem with the height of the switch in relation to the QL Key stem.

I do not want to modify the QL, so I will look into how a low profile Cherry switch can fitted without a problem.

The conne tion to the QL board is just a simple thin PCB to the QL board connectors.

The Tetroid solution, is an expansion on the circuit in the Aurora manual, to connect a QL Keyboard to the Aurora QL Keyboard connector.

Dave wrote:That switch requires 150g of force to actuate. The commonest actuation force is 45g, and 65g is considered ‘stiff’...

Yes that is why I arranged the switch footprint with large pads so it can take 6 mm switches or others like this diagonally between pads.
EziUsin-6-6-5-Silent-Botton-PCB-Keyboard-Light-Touch-Quiet-Micro-Switch
In case the first switch was too tough. The thread is "Noddy keyboard" because as I said I didn't envisage it as a professional typist keyboard for continuous use. However there are so many different types of surface mount switches that there is bound to be one that could make it as good as a membrane.

Derek_Stewart wrote: The Tetroid solution, is an expansion on the circuit in the Aurora manual, to connect a QL Keyboard to the Aurora QL Keyboard connector.

It looks a bit more advanced than that. It looks like a two pcb solution where one is the switch locator and a lower PCB connects the traces. It will work with an Aurora or a QL adapter. The QL adapter is shown in one of the pics.

This is a glorious keyboard that will fit really nicely. I will be buying one. I installed several of the Schon keyboards so I already know what will be involved. None of the cuts are visible. Cherry Brown is my favorite key.

I have shrunk the pads on the switch footprint because they were unnecessarily large. I made them stick past the pins of the biggest switch I might use so they are easy to solder and also fit smaller switches for versatility but some how they ended up at 750 when I aimed for 650 mil. Anyway it was really easy to change the pads and ripple it through to the PCB using Kicad. Now I am positioning the switches on the board in the right place I hope and there seems enough room around them to fit tracks where as putting the original switches pad to pad they didn't fit on the board.

Can you believe it Kicad 5 doesn't have autoroute but Kicad 4 does. How can you upgrade something with a downgrade, what a bunch of plonkers. Now I have to mess around with Freeroute to get some kind of an autorouter. I could have taped it quicker and had the PCBs back by now.

This might help if anyone else uses autorouting....https://techexplorations.com/blog/kicad ... utorouter/

I like to route my own pcbs, but that's just me!

Cheers,
Norm.

NormanDunbar wrote:
I like to route my own pcbs, but that's just me!

Nope, it's not. It's me as well. In my experience, 2-layer PCBS (might be different for more layers, but I don't do these) are much easier, better, and faster made without autorouter. KiKad's auto-placement of traces is just the right amount of "auto" that I think makes sense.

When I tried the auto-router in KiCad 4, I often found it tedious to remove and re-route wierdly routed traces placed by the autorouter that could have easily avoided with a bit of intuition or a single via. There's just too much degrees of freedom when starting with a blank PCB and an autorouter for it to do proper work (the first 5 minutes of placing traces decide greatly on the quality of a PCB, and the computer normally isn't very good at heuristics and guesswork).

Tobias