HELLO!
I'm trying to connect a 3 wire load sensor:
to an arduino uno using a LM741CN amplifier.
I'm basically just trying to detect a weight (not actual weight but just to detect that something there is a load on top of it) in a car seat. I'm confused as to how to start.
Wire it up like Figure 3 with just a single input.
http://masteringelectronicsdesign.com/how-to-derive-the-summing-amplifier-transfer-function/
Might want to use a single supply op amp instead. I think 741 needs +/- supply voltage.
http://www.national.com/ds/LM/LM741.pdf
I've connected the op amp on a breadboard with the resistors. Am I connecting the load senesor to the power inputs of the arduino or the analog input? What connection do I make from the arduino to the breadboard with the op amp?
White of load sensor to power.
Black of load sensorto ground.
Red of load sensorto op amp input.
Op amp output to Arduino analog pin.
Hi, I like CrossRoads' response but I wonder what I would do with INA125 amp
I have a loadcell with three wires: red black and white. the INA requires both + and - inputs, how do I accomplish this with a 3 wire loadcell?
I assume the Red will go to the + of the imput on the INA125, but what do i send to the -ve? I've been sending GND from the arduino there. Should I be doing something else? I haven't been able to pickup a reading on output side.
Hi donperry,
I've the same problem. Have you found a solution which wire you have to choose?
I have same problem please reply?
Better to start a new thread than to dig up old ones.
The other half of a bridge for the other input of the IC can be made with a second load cell (with supply and ground swapped). Or with two equal value resistors, e.g. 2x1k
Google something like "load cell half bridge diagram" (images).
Leo..
Wawa:
Better to start a new thread than to dig up old ones.
And better to start a new thread than do the dreaded cross post or hijack some other thread..