Electronics > Projects, Designs, and Technical Stuff

DIP Switch reliability in automotive

(1/5) > >>

Psi:
I'm looking at adding some DIP sw config options for switching between possible input signal types on an automotive product and I'm wondering what the reliability is like for dip switches in an automotive setting.

The product is in the passenger compartment so no engine vibration/heat.
The dip switches would just switch between AC or DC coupling by shorting/not-shorting a cap in series and shorting/not-shorting a parallel resistor.
The signals are either from a AC reluctance wheel speed sensor, or from a hall wheel speed sensor with DC offset.

Obviously the switches can't glitch or the signal would be affected.

Any thoughts.

One idea I had was to just use some opto isolators to connect/disconnect and use the dips to control them. Then I can add some noise rejection/filtering on the dips so any minor glitch's on the dip switches doesn't do anything.

Alternatively is there anything similar to a dip switch but more robust for automotive applications.

Psi:
Actually opto isolators probably wont work, in VR mode the input can be a few 100V and that makes the opto cost too high.

David Hess:
I do not remember having reliability problems with DIP switches in industrial settings.  We did have problems with DIP switches getting contaminated by flux cleaner, but that was solved by soldering them in place after cleaning or not immersing them.

KE5FX:
They are fine as long as nobody tries to reset them 20+ years later.  How long is the product expected to last?

sparkydog:
Are these meant to be changed after installation? If not, I might consider using jumpers rather than DIP switches, and some hot glue to make sure they don't go anywhere. You could also arrange for the installed PCB to have something pressing down on the jumper, which would allow it to be removed later while still holding it in place during operation. (Also, an advantage of a jumper is you can use three pins as a dual-pole switch, which sounds like it might be useful in your application?)

If you don't need to change settings after initial installation and don't mind a little extra labor cost, you could even use solder bridges; those almost certainly aren't going to care about vibration. In theory, you could also remove the solder to make changes, but doing so is non-trivially harder than jumpers or switches.

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod