Connecting resistive sensors

agarbino
Posts: 1
Joined: Fri Sep 04, 2009 7:14 am
Location: Houston, TX

Connecting resistive sensors

Postby agarbino » Fri Sep 04, 2009 7:22 am

I'm planning on using some potentiometers as sensors - basically wipers that (for example) sweep from 0-10kohm.
What's the best way to connect them?
- Power from DL1 5v ref or 12v car wiring harness?
- I assume a resistor in series (eg on the +ve line) would be appropriate to avoid shorting; so resistance from Power to pot goes from (X + 0)Ohm to (X+10K)ohm. What's the calculation for an X that maintains good resolution but does not draw too much current? How would it vary if I use a potentiometer with a different range?

Thanks!
Loving the new DL1!

Alex

jlucas
Posts: 302
Joined: Tue Nov 29, 2005 12:45 am
Location: East Liberty, OH
Contact:

Postby jlucas » Tue Sep 08, 2009 10:24 pm

You need a voltage divider circuit. Google it if your not familiar.

You definitely need a regulated voltage source, if you use the built in one keep in mind the limited current capacity or you can use a stand alone one (ex. Radio Shack 7805). Car 12v fluctuates and would render your data useless.

You can check the current draw with Ohm's law (I=V/R).

Set up a spreadsheet and you can quickly run through a couple options. There's even a few online calculators but it's much easier to keep track of what you've looked at with a spreadsheet.
Jeremy Lucas
Fast Tech Limited - a Race Technology Dealer

GMS Racing
Posts: 82
Joined: Wed Nov 29, 2006 10:36 pm
Location: South Africa
Contact:

Postby GMS Racing » Mon Sep 21, 2009 8:39 am

Regards,

Gary...
Johannesburg
South Africa


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