Drilling/Soldering new switches into PCB's [Advice]

[KHAANNN]

Hi everyone,

--- Background ---

I've previously converted the 1u + 1u top row of the infinity keyboard to an 2u one, it was pretty easy, I just drilled several holes until the switch could seat, hot-glued the switch in place, connected the switch to one of the 1u's by using the wires of a resistor (only used the wires of the resistor, it seemed like a nice wire material, easy to work with)

I'm not sure how much the hot-glue helps, but since the plate is 5mm, the friction should theoretically be enough to hold the switch in place during keycap changes

--- Current Project ---

With the 1u+1u to 2u conversion, I didn't have to disconnect any PCB paths, so it was pretty easy, but with the layouts I have in mind, I have to disconnect some of the paths that consist of the rows and columns of the keyboard, I would appreciate some advice, ideas in this stage

1) What would be the best type of wire to use for these purposes, would the type of wire change anything?
2) Should I solder the wire onto the PCB (the empty areas of the PCB are grounds, so it's challenging), or hope that the path that I disconnect connects two switch terminals and solder a wire to those terminals instead? (in the latter case, the wire would likely be 4-5cm's)
3) I'm also looking for a better approach than just superficially hot glue the switch from outside / under the pcb, I don't think that hot glue helps much, hot glue in general is pretty weak, but it's also safe and removable

Would appreciate any help / ideas,
Thanks in Advance :)

[suicidal_orange]

What an interesting project, I guess the controller is fully programmable including adding keys?

1 - Wire is wire, my ducky has a couple of runs of 15cm connecting the matrix to a Teensy with no ill effects.  If you use solid core it will stay flat to the board better and is easier to hold in place to solder, but it's also easier to break it if you bend it too much.  If you use stranded wire it will hang off the board unless it's tight between the two solder points or hot glued in place but you can bend it as much as you need.  For a small piece like you're suggesting I'd go for solid.

The main thing to consider is that it's pretty thin (think a strand of IDE cable, or computer fan wire) and unlike the leads from a resistor you want it in a rubber jacket so it doesn't short anything along the way.

2 - The switches will be connected to other switches on one terminal, the other goes to a diode.  The other side of the diode will be connected to the other side of other switch's diodes so you can solder between the switches or diodes avoiding any broken links completely.  You could scrape off the solder mask either side of the break and do a little loop around it, but it's more fiddly and you'd still have to solder two joints so not worth the effort.

3 - I like hot glue, the only conventional alternative I could come up with is sugru which sticks more semi-permanently.

For an off the wall idea make a big (bigger than the switch) sutround for the big pin on the bottom of the switch from from transparent plastic packaging, put the switch through the PCB and the trans surround and use gel superglue to glue the switch to the surround using a thick spike from each side.  If you want to remove the switch at a later date you should be able to snap the spikes off with a pair of pliers.

Not sure this is a good idea, you might want to wait for someone else's input )


If you have the plate off at the moment don't forget to take some nice pics of both sides of the PCB showing the traces in the area around where you're modding, that way if you have any problems working out what to connect where it will be easier for someone to help

[KHAANNN]

Thanks a lot for the ideas, the controller is fully programmable, but I just move or remove keys, so the task is as simple as editing the base map (infinity keyboard / controller)

The motor-wire idea sounds great, for insulation I will probably use scotch tape after the modifications are completed

I didn't get your off the wall idea completely, but the switch doesn't have to survive possible/future removals, I'm considering hot glueing the switch from the sides (to the 5mm plate) and implosively removing/destroying the switch in place if issues occur with the switch in the future - but it's obviously challenging to apply the glue / the right amount of glue, as it could cool down before the switch is inserted, or creep out too much / prevent insertion etc.

I also think I need a new hot glue setup, my transportable bosch hot glue gun is practical, yet the result is almost always weak, easily removable, I'm guessing a higher temp hot glue gun and better glue sticks might make the "push glue from bottom" method work

[suicidal_orange]

In that case can you insert the switch in the plate and glue it there before soldering it to the PCB?  If you get too much glue you can always trim it with a knife.  If you snap off the plate mounting flaps there is a big hole on two sides of the switch to get glue into which should hold pretty well.

[KHAANNN]

In that case can you insert the switch in the plate and glue it there before soldering it to the PCB?  If you get too much glue you can always trim it with a knife.  If you snap off the plate mounting flaps there is a big hole on two sides of the switch to get glue into which should hold pretty well.

Very possible, the removal of the nudge is a great idea, I will test it on a sample plate/switch and try to pull the switch out afterwards