buttons that don't register well

If you're having problems with the hardware of a DM41X or DM42, post about them here.
Zaphod
Posts: 24
Joined: Sat Mar 31, 2018 11:34 pm

Re: buttons that don't register well

Post by Zaphod »

One of the things that slightly bothers me about this calc (I’ve not got one but I can read) is the use of dome/dimple switches .....

Was there a particular reason why, say , low profile surface mount tact switches weren’t used instead ?
Michael
Site Admin
Posts: 243
Joined: Wed Apr 05, 2017 11:31 pm

Re: buttons that don't register well

Post by Michael »

Zaphod wrote:
Wed Apr 04, 2018 10:59 pm
Was there a particular reason why, say , low profile surface mount tact switches weren’t used instead ?
The reason for not using tact switches is because they are too noisy.
User avatar
H2X
Posts: 605
Joined: Tue Apr 25, 2017 8:00 am
Location: Norway

Re: buttons that don't register well

Post by H2X »

Michael wrote:
Wed Apr 04, 2018 11:26 pm
The reason for not using tact switches is because they are too noisy.
The decision has been made, obviously, but how noisy were they? What kind of switches were considered?
DM42 #40 running C43 | DM41X #50 | various HP models
The earth is flat. It just appears round because it is massive and curves spacetime.
Michael
Site Admin
Posts: 243
Joined: Wed Apr 05, 2017 11:31 pm

Re: buttons that don't register well

Post by Michael »

H2X wrote:
Thu Apr 05, 2018 9:40 am
The decision has been made, obviously, but how noisy were they? What kind of switches were considered?
I tried many different kinds. They all were too noisy, NG for use in a library or during a test.
All have some dome inside, the diameter and the thickness of the dome affect how they sound and the force needed to press it.
The current domes are 9mm in diameter and I haven't found any low profile tact switch with a dome larger than 6mm.
But please make a suggestion for a better switch. I'm very curious.
User avatar
H2X
Posts: 605
Joined: Tue Apr 25, 2017 8:00 am
Location: Norway

Re: buttons that don't register well

Post by H2X »

Michael wrote:
Thu Apr 05, 2018 9:56 am
I tried many different kinds. They all were too noisy, NG for use in a library or during a test.
Valid point!
Michael wrote:
Thu Apr 05, 2018 9:56 am
But please make a suggestion for a better switch. I'm very curious.
Alas, I don't have expertise in this area. As I have pointed out elsewhere, I am fully aware that I am nitpicking. Well, partly so - there are obviously some reports of button misbehaviour / inconsistencies, which should not happen (my ENTER key is mushy on the left side, and there are other reports). The nitpicking part is that I would personally prefer a bit softer feel - like the best HP's. How did they manage it?
DM42 #40 running C43 | DM41X #50 | various HP models
The earth is flat. It just appears round because it is massive and curves spacetime.
Zaphod
Posts: 24
Joined: Sat Mar 31, 2018 11:34 pm

Re: buttons that don't register well

Post by Zaphod »

All have some dome inside
Yes of course they are dome too inside.
the diameter and the thickness of the dome affect how they sound and the force needed to press it.
but I wouldn't call them noisy per se... and you can specify operating pressure from quite a few suppliers too

Here for example:
https://docs-emea.rs-online.com/webdocs ... 4b0fc9.pdf
Supplied in three different operating force versions
ALPS, Wurth do plenty too

Here's an ALPS, version that comes in four different operating force options
https://docs-emea.rs-online.com/webdocs ... 4b0fb3.pdf

Depends on how much clearance from top of the switch to the bottom of the button you have got ?

I have some surface mount dome switches here that you can't really hear, the dome is more or less exposed (Kapton film over the top) but on it's own substrate.

The main benefit I can see is ease of replacement
Michael
Site Admin
Posts: 243
Joined: Wed Apr 05, 2017 11:31 pm

Re: buttons that don't register well

Post by Michael »

H2X wrote:
Thu Apr 05, 2018 11:11 am
The nitpicking part is that I would personally prefer a bit softer feel - like the best HP's. How did they manage it?
As mentioned, the force needed on the domes depends on their thickness.
Then the plastic hinge of each button adds up too to the total force needed.
The thinner the domes and the hinges are, the more likely they'll break.
Current domes need 150gr force, I'll try 120gr ...
User avatar
H2X
Posts: 605
Joined: Tue Apr 25, 2017 8:00 am
Location: Norway

Re: buttons that don't register well

Post by H2X »

Michael wrote:
Thu Apr 05, 2018 11:21 am
H2X wrote:
Thu Apr 05, 2018 11:11 am
The nitpicking part is that I would personally prefer a bit softer feel - like the best HP's. How did they manage it?
As mentioned, the force needed on the domes depends on their thickness.
Then the plastic hinge of each button adds up too to the total force needed.
The thinner the domes and the hinges are, the more likely they'll break.
Current domes need 150gr force, I'll try 120gr ...
Wow, good news (for me, at least)! I'd be happy to test them... :-)
DM42 #40 running C43 | DM41X #50 | various HP models
The earth is flat. It just appears round because it is massive and curves spacetime.
Michael
Site Admin
Posts: 243
Joined: Wed Apr 05, 2017 11:31 pm

Re: buttons that don't register well

Post by Michael »

Zaphod wrote:
Thu Apr 05, 2018 11:18 am
I have some surface mount dome switches here that you can't really hear, the dome is more or less exposed (Kapton film over the top) but on it's own substrate.
It depends a lot on how everything is put together. Of course the switch is on a PCB in the end, but try putting a single one on a wooden surface and press the dome with something hard.
Zaphod
Posts: 24
Joined: Sat Mar 31, 2018 11:34 pm

Re: buttons that don't register well

Post by Zaphod »

I agree

But a (thin foam etc) sheet could be added to damp down any excess noise of operation perhaps.
Post Reply