Level Sensors

Other Hardware Sensors
1

Hi List,
this is my fist approach to the electronic word I would like to connect the arduino with a Level Sensor here the data:
Rated Power (max.) 100 W
Switching Voltage 400 V
Switching Current (max.) 1.0 A
Carry Current (max.) 2.5 A
Contact Resistance (max.) 150 mOhm
@ 0.5V & 10mA

I now that i should calculate the Ohm Law but im completly lost:

  1. mOhm means micro ohms or mega ohms?
  2. Arduino shoud have 5V and this is the only part of equation clear

but to calculate the resistor where i find the amount of ampere used by the device ?

2

That data is totally strange for a level sensor. Any link to its datasheet?

3

Yes

https://standexelectronics.com/resources/technical-library/technical-papers/datasheet-ls03-series-liquid-level-sensor/

http://www.gotronic.fr/art-detecteur-de-niveau-no-mls31a-11545.htm

4

It's a level switch / float switch, no need to calculate anything.

If it's got two wires then connect one to an Arduino digital pin, the other to a ground pin (GND). Use this in setup()...pinMode(mySwitchPin, INPUT_PULLUP);
and read the switch with mySwitchState = digitalRead(mySwitchPin);

Note: try and keep the water out of the Arduino when playing with float switches :slight_smile:

5

Ok thanks for the answer, but your answer then generate immediatly another:
When I've to use the resistor ?
into the aurdunio start kit book it's used a restistor even with a swith (push botton ) on/off
I also find this article about level sensor and it also consider the use of resitor

6

If you use INPUT_PULLUP, as suggested by Martin-X, there is generally no need for a resistor.

This similar example may help:

7

Thanks to all for your helps

8

Sorry I didn't give an explanation. To add a bit more to @Archibald's reply, have a look at these:

https://learn.sparkfun.com/tutorials/switch-basics

http://playground.arduino.cc/CommonTopics/PullUpDownResistor

and if you want to calculate the resistor value for yourself...
https://learn.sparkfun.com/tutorials/pull-up-resistors

and to answer the first part of your question, a lower case m prefix means milli (one thousandth).