×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Silicone Rubber Keypad Experience?

Silicone Rubber Keypad Experience?

Silicone Rubber Keypad Experience?

(OP)
I'd like to use a silicone rubber keypad for our products.  However, my experience with membrane switches hasn't been good.  I find that many, over time, have trouble making electrical contact.  I'm guessing a film develops on the PCB.  Is the contact technology better these days?  What would I need to specify for the board and the conductive pill to make sure I have a long-lasting contact?  Any good web resources?

RE: Silicone Rubber Keypad Experience?

When we did work on this (10,000+ units shipped and working)we put carbon loaded ink on the pcb tracks so there was a "carbon to carbon" contact rather than "carbon to copper" or "carbon to gold" or "carbon to tin-lead".  Use a pcb vendor with experience of these carbon ink patterns. The resistance is much higher than you would expect for an ordinary switch; say hundreds of ohms worst case. Nevertheless it is easy to detect the difference between hundreds of ohms and tens of megohms.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources