Measuring resistance?

[UnhappyWithoutU]

Is it possible to measure the resistance like given in this Tutorial?

https://create.arduino.cc/projecthub/iasonas-christoulakis/how-to-make-an-arduino-ohm-meter-90fda8

Thanks!

 

[Frank B]

Nice project.
However..

[...]the error here is greater than 100%.[...]

The problem is easily fixed by using a known resistor that’s closer in value to the unknown resistor. Once I replaced the 1K Ohm known resistor with a 100K Ohm resistor, the accuracy of the measurements improved greatly.

Not sure if the author was aware of what he wrote.. "close to the unknown resistor" is a little bit difficult - its unknown And you don't know the error.

Finally, all the known resistors have an error 1.6-200%.But we can easily measure resistors without having a multimeter.

Yes.. measure with error 200%

Still it's a nice project - and fun to do, for a beginner - but in now mean a replacement for a multimeter It's just fun.
Also, the "Multi" in "Multimeter" means you can measure more than just restiance.

 

[UnhappyWithoutU]

Hey, my current project is to add a indicator stalk for simulators like Truck Simulator 2.
The stalk however works with resistance, which increases or sink when I press or move buttons.

Thats the only way I know for now

 

[UnhappyWithoutU]

Zudem könnten wir deutsch schreiben wenn es erlaubt ist

 

[Frank B]

For this, its ok. And do don't need to know the absolute value in this case.
No German please

 

[UnhappyWithoutU]

Okay, so a teensy would be able to do that?
By measuring voltage to calculate the resistance?
Like the Arduino can.

 

[UnhappyWithoutU]

Version 4.1 in my case

 

[Frank B]

It can do it- but don't use 5V. 5V can destroy the Teensy. Use 3.3V instead.

 

[defragster]

Zudem könnten wir deutsch schreiben wenn es erlaubt ist

Translates to : "‎In addition, we could write german if it is allowed‎"

It is allowed ... Some few folks like Frank B are native German speakers ... for the rest of us it takes a translation so posts may be ignored without translation provided.

Though 'right click translate selection' worked well in place on that one. No doubt in some cases though translation can intorduce confusion.

Es ist erlaubt ... Einige wenige Leute wie Frank B. sind deutsche Muttersprachler ... für den Rest von uns braucht es eine Übersetzung, so dass Beiträge ohne Übersetzung ignoriert werden können.

Obwohl 'Rechtsklick-Übersetzungsauswahl' in diesem Fall gut funktioniert hat. Zweifellos kann die Übersetzung in einigen Fällen Verwirrung stiften.

<edit>: that was fun - but should have hit refresh first ...

 

[UnhappyWithoutU]

But is there a way to measure resistance without any voltage? Like a Multimeter does

 

[Frank B]

Yes.. "Rechtsklick-Übersetzungsauswahl" is a nice word.. read it the first time

 

[Frank B]

A multimeter uses a voltage to measure resistance.. No way without

 

[defragster]

Yes.. "Rechtsklick-Übersetzungsauswahl" is a nice word.. read it the first time

Yes it was FUN reading that 'compounded' German word ... I saw single quotes around it so that pointed right to the English.

 

[UnhappyWithoutU]

I heard that the resistors are getting really fast really warm. Any way to avoid grilling them in time?

 

[UnhappyWithoutU]

Yes it was FUN reading that 'compounded' German word ... I saw single quotes around it so that pointed right to the English.

However, there are words that are longer. haha

 

[Frank B]

Only if the resistance is very low.
There are smarter ways, but they are more complicated, too.

 

[Frank B]

Yes in German you can create words that are very very long... and still, everybody knows what they mean

 

[UnhappyWithoutU]

Only if the resistance is very low.
There are smarter ways, but they are more complicated, too.

What exactly is low? And Do you have a tutorial or explanation how to do it

 

[Frank B]

They heat up when the current is too high.
Search "Ohmsches Gesetz" on Wikipedia to calculate the current.
However, this again depends on how much current (better: Watts) and heat dissipation the resistor was built.
I.e. 1/8 watt, or 1/4 watt etc..

I'm sure there will be others who post formulas here..
Sry, I don't know a tutorial.

For 3Volt, usually a few Ohms.

Edit: don' draw more than a few (well below 10mA) from a teensy i/o pin.

 

[Frank B]

Just avoid less than 100 .. 200 Ohms and everything is ok..

 

[PaulStoffregen]

A multimeter uses a voltage to measure resistance.. No way without

Most multimeters pass a regulated current through the resistor and measure the resulting voltage, using the same circuitry they have for DC voltage measurements.

You can make a regulated current circuit, but it usually involves an opamp, a transistor, and at least 1 resistor. Not so simple.