Switches (bulges and gaps)

[Ralph Sommerer]

Hi everyone,

I received my kit last week, I've done all the LEDs and setup the raspi and everything, and now I'm doing the switches.

I noticed that my switches have awkward bulges of insulator material around the pins that prevent me from pushing them all in. Also, they're of different heights (the white switches have the least amount).

I'm going to file down somewhat the biggest bulges, and the bracket should make sure that all switches are on the same height above the pcb.

Still, how critical is it for the switches to sit flush on the PCB? Mine are about 1mm above it (I have only tack-soldered them so far).

Thanks, Ralph

[david richards]

Greetings Ralph, I simply ensured that all the switches were in at the same level, it did not seem to matter that they were not flush.

Kind regards, David.

On Thursday, 15 March 2018 09:38:27 UTC, Ralph Sommerer wrote:

Hi everyone,

I received my kit last week, I've done all the LEDs and setup the raspi and everything, and now I'm doing the switches.

I noticed that my switches have awkward bulges of insulator material around the pins that prevent me from pushing them all in. Also, they're of different heights (the white switches have the least amount).

Thanks, Ralph

[Obsolescence]

David, Ralph,

Indeed, the glue bulges around the pins are non-critical. The switches don't sit flush on the PCB, the glue bulges make them sit a bit above the PCB and that's fine. As long as all of them sit the same 0.5mm or whatever above the PCB. This is curprisingly noncritical for the end result.

If one glue bulge is extremely bigger than the others, I break/clip/snip them down to size with a side cutter, so they are similar to the others. But it's almost never necessary.

Ralph, just for confirmation, your switches sit much more flush than mine ever did.

Kind regards,

Oscar.

[Warren Young]

On Thursday, March 15, 2018 at 4:05:10 AM UTC-6, Obsolescence wrote:

Indeed, the glue bulges around the pins are non-critical.

More than that, it's absolutely normal for wire-mount switches, which is what was used for this kit. That's why they have a loop in the solder lug: so you can wrap the wire around it, else you'd need three hands to solder the connection.

I don't think I've expressed this idea before, and it's probably too late now, but there is such a thing as PCB-mount switches, which are made to mount flush. Oscar, are those being used with the PiDP-11?

[Ralph Sommerer]

Thanks to everyone.

I cut the bulges down using Oscar's method (with a side cutter). I trimmed about half of the switches.

Here's the method I ended up using, which -- for brevity sake -- I'll call "the method I ended up using" :-)

1. I soldered the bracket with the two outermost slots onto the PCB. I checked that the the switches were "exactly" the same height (ruler/eyeball).
   
2. I soldered a brown toggle in the middle of the bracket and used a ruler to make sure it was the same height as the outermost ones. Soldering its tab to the bracket prevents it (bracket) from sagging.
3. I then filled the bracket from left to right, always checking with a ruler (plus eyeballing across the various edges) that the height was correct.
4. If a switch didn't align with the others neatly in a row, I flipped them around (toggles only) or bent the pins a bit. If it still looks crooked, think vintage...

I'm done for today (all center pins soldered). Contrary to the designer's intentions, I'll solder the switches' tabs to the bracket last (if at all).

Thanks again to everybody for their assistance.

[Oscar Vermeulen]

Warren,

On 15 March 2018 at 14:57, Warren Young <tange...@gmail.com> wrote:

I don't think I've expressed this idea before, and it's probably too late now, but there is such a thing as PCB-mount switches, which are made to mount flush. Oscar, are those being used with the PiDP-11?

At the time I ordered them, they couldn't offer them. But as I am getting close to the end of my stash of 8 switches (plenty of 11 switches yet, although hopefully that'll change RSN now) I will ask them again. It's a bit odd that they could not offer them.

Kind regards,

Oscar.

[Warren Young]

On Saturday, March 17, 2018 at 2:34:55 AM UTC-6, Obsolescence wrote:

On 15 March 2018 at 14:57, Warren Young wrote:

I don't think I've expressed this idea before, and it's probably too late now, but there is such a thing as PCB-mount switches, which are made to mount flush. Oscar, are those being used with the PiDP-11?

At the time I ordered them, they couldn't offer them. But as I am getting close to the end of my stash of 8 switches (plenty of 11 switches yet, although hopefully that'll change RSN now) I will ask them again. It's a bit odd that they could not offer them.

One nice thing about PCB-mount switches is that they typically use much smaller pins, which allows much more precise placement on the PCB. You could probably get away from the whole switch bracket alignment scheme by moving to PCB-mount switches.

But again, I expect this idea is coming in way too late to affect anything. Oh, well.

[Obsolescence]

Warren,

On Saturday, March 17, 2018 at 8:14:45 PM UTC+1, Warren Young wrote:

One nice thing about PCB-mount switches is that they typically use much smaller pins, which allows much more precise placement on the PCB. You could probably get away from the whole switch bracket alignment scheme by moving to PCB-mount switches.

But again, I expect this idea is coming in way too late to affect anything. Oh, well.

Not quite... I am coming to the end of my PiDP-8 switch stash (schwitch schtasch?). So I have to re-order again.
Problem is, the practical minimum order quantity is 26,000 switches... gulp.

But if I make the jump, I can at least ask if they can make PCB-mount switches now. They didn't want to do that before, but it's been two years or so since I ordered last time!

Kind regards,

Oscar.

[Warren Young]

On Saturday, March 17, 2018 at 3:51:35 PM UTC-6, Obsolescence wrote:

I am coming to the end of my PiDP-8 switch stash (schwitch schtasch?). So I have to re-order again.
Problem is, the practical minimum order quantity is 26,000 switches... gulp.

It may be that there is not a market for 1000 more PiDP-8/Is. You might be at the last run now. I'm rather surprised you've been able to keep the orders going this long.

If you decide that a market for at least one more production run does exist, I hope you'll consider redesigning the PCBs for a "v2" run. You must have collected many such ideas over the years. To that list, you can add one more: use smaller thru-holes for the PCB-mount switches, so you don't need the switch bracket for alignment.

[will....@gmail.com]

I bought one of the original PiP8 kits and assembled it without too much difficulty. I worked out my own solution for aligning the switches.

Each switch has a small pin attaching the plastic top (the part which you paint) to the actual switch. These pins are easy to remove and a bought a rod of the same diameter but long enough to pass through all of the switches replacing the individual pins. The result is a single assembly with the rod passing through all of the switches.

I found this kept the switched perfectly aligned  as I pushed the switch contacts through the PCB holes and soldered them to the PCB.

I also used small springs to make those switches that are meant to be momentory contact return to their off position.

[Dan Hale]

Thanks for this tip, but more details will help.  Where did you get the rod and the springs?  What are their specifications (length, diameter, etc,)  

[will....@gmail.com]

The springs came from dismantling used disposble lighters (I don't smoke.) I drilled a small hole in the metal of the switch where the spring rests and inserted a small round head screw which fits inside the spring to stop it wandering off.

The rod is brass and is the kind of thing model makers use. It came from Ebay. Obviously the rod has to be long enough to hold all the switches.

I did this a few years back so I don't have the rod diameter  to hand any more but it looks to be 2mm.