[IC] Single switch PCB

[mkawa]

medium run can be up to a month lead-time. geekhackers is currently unable to absorb the up-front costs, but this could be set up as a preorder on the storefront, and there are no major tax issues, since geekhackers is a properly registered retail business entity. would prefer to discuss with you and mohit and grab a sample for myself first. i have talked on and off about this with moz, but if it becomes serious, there are many more things to think about before launching.

[samwisekoi]

I know I am late to this parade, but it is very interesting. Great work! 

I have a contribution/suggestion for a v.3 or simply another way to order the v.2 micro-PCBs:

Make them in 15-switch break-apart rows on 0.75" centers.  Include traces for the row connections along with the existing pads.

That way the long runs of switches can be connected with a single PCB, and mods and shorter runs can be made by snipping the 15-switch rows.  And for people who want them to be completely separate micro-PCBs, just cut them all apart.  To make a square matrix, simply cut the row traces in the middle of a row.

Having made a few hard-wired keyboards, I think such a creature would make most designs very, very simple to build.

Is this interesting to anyone else?  If so I can do a mock-up image.

 - Ron | samwisekoi

[mkawa]

that is a very very good idea. if geeckers produces and sells the run, these are exactly the types of ideas i'd like to roll in before production. my feeling is that the goal of these is to make custom layouts as simple as possible. imagine an MS ergo style humpy-type of board where there there is one side of the board that is relatively normal, just at an angle, and the other side of the board has to be molded or printed with disjoint switch mounts. this one run of PCBs should help the person making that as much as possible. so whenever possible, it should be possible to just jumper them together at fixed placements, but when oddness is needed, snap 'em off and go to town.

[swill]

I know I am late to this parade, but it is very interesting. Great work! 

I have a contribution/suggestion for a v.3 or simply another way to order the v.2 micro-PCBs:

Make them in 15-switch break-apart rows on 0.75" centers.  Include traces for the row connections along with the existing pads.

That way the long runs of switches can be connected with a single PCB, and mods and shorter runs can be made by snipping the 15-switch rows.  And for people who want them to be completely separate micro-PCBs, just cut them all apart.  To make a square matrix, simply cut the row traces in the middle of a row.

Having made a few hard-wired keyboards, I think such a creature would make most designs very, very simple to build.

Is this interesting to anyone else?  If so I can do a mock-up image.

 - Ron | samwisekoi

I was also thinking this would be a good idea for this today. 

I am also interested in a bunch of these.

[Melvang]

While I like this idea it would make them more expensive as the customer will end up paying for the space between switches.  At least if OshPark is the producer, since they charge based on area. 

Plus part of my goal with this design was to be able to solder the switch to the PCB and at least one end of the jumpers before installing into the plate.

The advantage with this is you can change stems and springs without having to desolder anything when using a stock plate.  Also, the cad work for square holes is quicker, easier, and cheaper to produce (less machine time).

Also this size is actually required for my build as my plate extends past the bottom of the switches.

[swill]

While I like this idea it would make them more expensive as the customer will end up paying for the space between switches.  At least if OshPark is the producer, since they charge based on area. 

Plus part of my goal with this design was to be able to solder the switch to the PCB and at least one end of the jumpers before installing into the plate.

The advantage with this is you can change stems and springs without having to desolder anything when using a stock plate.  Also, the cad work for square holes is quicker, easier, and cheaper to produce (less machine time).

Also this size is actually required for my build as my plate extends past the bottom of the switches.

Interesting.  I see the value in this as well.  You are going to have to plate mount these anyway.  I will be interested to see if it is easy to line up the single switches in the plate or if the movement in the plate could cause switches to be slightly off alignment.  I would need to hand wire a board before I would understand this aspect.

[mkawa]

they have pcb mount holes don't they? if you have to plate mount them, it kind of defeats the purpose. there are very few people building 1/4" stainless steel plated keyboards.

[Melvang]

they have pcb mount holes don't they? if you have to plate mount them, it kind of defeats the purpose. there are very few people building 1/4" stainless steel plated keyboards.

Version 2.0 does not have have the two pcb mount holes.  But getting them square enough to fit through the hole in the plate isn't hard at all.

• Put about half the solder you normally would on the right hand pin (when viewing from the bottom as you would soldering the switch) and let cool
• With index finger and thumb on the top and bottom edge of the PCB overlapping onto the switch, reflow the solder on that same joint.  When it is hot the PCB should center on the switch
• Solder the other pin.

The reason I say to start with the right hand pin is because the left hand pin is basically a slot and has a lot more play in it.  So starting with the right hand pin gets you a lot closer in the beginning.  This isn't as much of an issue with MX switches as Alps because of the center pin but works the same for both. 

I currently have a set of 9 soldered up in a working matrix.  I will post pics of it later tonight.

[Melvang]

Potato pics inc.


This is the backside with the jumpers installed.  I used 22 ga. stranded wire, 20 ga. will not fit.


This shot shows that they are indeed compatible with both MX and Alps switches.


Switch can be removed from plate without desoldering (given enough length in the wire) for swapping stems and springs.

[Melvang]

Just got an email back from OshPark and due to the way they price on area the next price break after 150 square inches (600 units) is at 1000 square inches (4000 units).  Not real sure if we could actually hit that or not but we will see.  If we start getting close to that number I will get back in touch with Dan at OshPark for an updated price.  At 600 units the price is $1 per square inch or $0.25 per PCB.

[samwisekoi]

OK, I knocked this out using Pad2Pad.  It is a run of 16 MX switches with all holes, a row trace, SMD diode pads and row and column pads.  It is 11.75" x 0.50".


MX Keyswitch PCB strip mockup by samwisekoi.

Estimated job cost for 25 strips is $204.39, $8.18 per strip, or $0.51 (51 cents) per switch.

Estimated job cost for 100 strips is $268.98, $2.69 per strip, or $0.17 (17 cents) per switch.

I chose 16-position strips so it was divisible by four, making things like 10-key pads simpler.  At 100 strips per job, a 5-row, 60% keyboard would cost $13.45.  A full 104-key keyboard would need 10 (+/-), for a total cost of $26.90 in PCB strips alone.

And as someone who has made a few hard-wired keyboards by hand, this would have been a god-send.

Thoughts?

 - Ron | samwisekoi

p.s.  I mocked-up a 60% keyboard.  The green lines are the column wires and a few row extensions for the mods.  It turned out to only need four of the strips if I used the cut-offs from the other rows.


MX Keyswitch PCB strip 60% mockup by samwisekoi.

[Defect]

Depending on final price,  I'd either want a handful or a few crates

[Melvang]

Depending on final price,  I'd either want a handful or a few crates

For my version it look like the price is going to be the following.
3-600 units $1.25 each
600-4000 units $0.25 each
4000+ ?

[AKmalamute]

For my version it look like the price is going to be the following.
3-600 units $1.25 each
600-4000 units $0.25 each
4000+ ?

Hitting 4,000 switches would probably require about 25 people. Assuming that drops it to $.22 / ea (random guess) it would be $41 + tax + PP + shipping, or $52 average per-person, assuming $8 avg gets the shipping done, and tax is already collected by OSHpark. (at roughly 185 switchboards per person)

 Doable, in terms of interest. Figuring ~ 10% dropout, you'd need to wait 'til you were at ~30 orders, then start invoicing to make sure you had the cash for the 4,000+ board order.

[mkawa]

OK, I knocked this out using Pad2Pad.  It is a run of 16 MX switches with all holes, a row trace, SMD diode pads and row and column pads.  It is 11.75" x 0.50".

(Attachment Link)
MX Keyswitch PCB strip mockup by samwisekoi.

Estimated job cost for 25 strips is $204.39, $8.18 per strip, or $0.51 (51 cents) per switch.

Estimated job cost for 100 strips is $268.98, $2.69 per strip, or $0.17 (17 cents) per switch.

I chose 16-position strips so it was divisible by four, making things like 10-key pads simpler.  At 100 strips per job, a 5-row, 60% keyboard would cost $13.45.  A full 104-key keyboard would need 10 (+/-), for a total cost of $26.90 in PCB strips alone.

And as someone who has made a few hard-wired keyboards by hand, this would have been a god-send.

Thoughts?

 - Ron | samwisekoi

p.s.  I mocked-up a 60% keyboard.  The green lines are the column wires and a few row extensions for the mods.  It turned out to only need four of the strips if I used the cut-offs from the other rows.

(Attachment Link)
MX Keyswitch PCB strip 60% mockup by samwisekoi.

my thought is to take it to pcbwing for a significantly larger order once the design is polished; in particular, i think it needs PCB mount holes, even if some smt pads have to be sacrificed for it.

oddly shaped pcbs can also be difficult to distribute. see eevblog's videos on micro ruler distribution. particulary because this one is going to have a lot of perforation, some thought will need to be put into packaging so that costs don't run away on that.

my original idea on distributing these, that i talked to melvang and moz about was to make the pcbs slightly larger for easier wiring, but then i actually remembered that sorbothane has a mold that is exactly this size and is pretty inexpensive per piece in serious volume. it would quite cool to package these with matching sorbothane pads. the sorbothane is both a dampener, a very sticky surface to make weird constructions easier to put together, and an excellent dieletric.

[Melvang]

Group buy is Live

Click here

[berserkfan]

Pardon me if I don't understand anything, but it looks as though you guys are just using the PCB to solder the switch, and then planning on hand wiring everything right?

Then what's the difference between getting any old PCB, and sawing it up into little squares, and hand wiring these?

I hate to throw away old stuff. (Environmental concerns). Not to mention, I have a few G80 PCBs now. Happy to give away for the cost of shipping.

[Melvang]

1.  Pardon me if I don't understand anything, but it looks as though you guys are just using the PCB to solder the switch, and then planning on hand wiring everything right?

2.  Then what's the difference between getting any old PCB, and sawing it up into little squares, and hand wiring these?

I hate to throw away old stuff. (Environmental concerns). Not to mention, I have a few G80 PCBs now. Happy to give away for the cost of shipping.

I understand your concerns.

1.  This will be much easier to solder up due to having through holes to solder interconnects to.  Granted yes it is more soldering but it is a lot easier to solder a wire to a plated through hole than trying to solder a wire to a trace.

2.  Easier soldering and PCBs have a lot of very nasty chemicals in them and release fiber glass particles into the air that you really don't want floating around your house especially if you have little ones.

[jdcarpe]

Pardon me if I don't understand anything, but it looks as though you guys are just using the PCB to solder the switch, and then planning on hand wiring everything right?

Then what's the difference between getting any old PCB, and sawing it up into little squares, and hand wiring these?

I hate to throw away old stuff. (Environmental concerns). Not to mention, I have a few G80 PCBs now. Happy to give away for the cost of shipping.

These have traces and pads/holes for not only the switch itself, but for diodes, LEDs, resistors, as well as pads for the connecting wires.