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Electronics => Projects, Designs, and Technical Stuff => Topic started by: tru3533 on August 16, 2021, 09:31:00 pm

Title: 8 position selector switch to multimeter
Post by: tru3533 on August 16, 2021, 09:31:00 pm

Hi,
I`m looking at a project where I need a function where the user select from 8 different signals.
Signals to be measured are voltage up to 12VDC and ohm.
Output is connected to a multimeter

The obvious solution is to use a 2 pole 8 position rotary selector switch, but not that elegant  :)

Can you help with a solution that is more useful, and not mechanical?

Title: Re: 8 position selector switch to multimeter
Post by: David Hess on August 17, 2021, 02:52:52 am

What is wrong with an 8 position double pole switch?

The obvious alternative is an 8 position switch and relays which might be better in some applications.

Depending on the ohm measurements, semiconductor switches are possible but that is even more complicated than relays.

Title: Re: 8 position selector switch to multimeter
Post by: tru3533 on August 17, 2021, 09:59:48 am

The biggest drawback is price.

The best solution I have found so far is
https://www.digikey.com/en/products/detail/grayhill-inc/51ST22-01-2-08N/7686275 (https://www.digikey.com/en/products/detail/grayhill-inc/51ST22-01-2-08N/7686275)

Switch + knob = $25

Ideal price range would be $10

Finding a 2 pole 8 position switch for pcb mount in that price range is not easy.

I have a MCU on the board so miniature relay solution is possible, what would be the goto relay here?

Title: Re: 8 position selector switch to multimeter
Post by: Nusa on August 17, 2021, 10:08:52 am

I don't think you're going to find or make a different solution that costs less than $25, not counting labor.

Title: Re: 8 position selector switch to multimeter
Post by: tru3533 on August 17, 2021, 10:47:16 am

I was hoping I overlooked something :)
Including the switch, maybe some common ground can simplify the solution?
 

Title: Re: 8 position selector switch to multimeter
Post by: tru3533 on August 17, 2021, 12:01:43 pm

This discussion got me going.

1 rotary switch 1 pole 8 positions = $2.30
1 knob
2 relays

Now how to activate the relays when in position 7 or 8?

Title: Re: 8 position selector switch to multimeter
Post by: tru3533 on August 17, 2021, 01:04:08 pm

OK, this is what I have for now.
Reducing the switch to 1 pole 6 position
Adding 2 buttons

Do someone have a even simpler solution?

Title: Re: 8 position selector switch to multimeter
Post by: Nusa on August 17, 2021, 04:23:52 pm

You're using a button and a relay and a 5V power supply to do the same thing a dpdt switch would do? Times two.

Title: Re: 8 position selector switch to multimeter
Post by: tru3533 on August 17, 2021, 08:54:58 pm

You are so right Nusa :)
And the price dropped to $0.6 for each button. = $1.2
+ caps for buttons +rotary switch $ 2.30
Total $ 4 for complete solution