Help! D:

hi im trying to connect current sensor ACS712 with the arduino. however it seems like the output of the ACS712 is always fixed no matter how much voltage i apply it. can someone show me how i should connect it????? thanks :)

Show us how you have connected it, or, do a search in the box at top of page.


this is how i connect my circuit


Please supply a picture that allows us to see the connection details rather than a low resolution blur.


here you go. this is how i connected my circuit

The amount of current passing through the sensor will be so small it will be hard to detect a change as you vary the voltage.

With a 1k resistor and a LED you'll be getting about 10mA of current. The sensor outputs 185mV/A so with 10mA the sensor should be outputting 1.85mV. Each unit from the Arduino's ADC represents about 5mV.

I think you're not passing nearly enough current through the sensor to be detected.

BTW, As instructed by the thread "How to use this forum", please use a meaningful title to your post. If every person asking for help titled their thread "Help", the lists of posts would be pretty meaningless.

so does it help by increasing/decreasing the gain or the volt ref?

These devices are meant to measure Amps rather than mA. The resolution is too low for very small currents.

Test the circuit using a larger current draw. Say something drawing an Amp or two.


randytan: so does it help by increasing/decreasing the gain or the volt ref?

I doubt it.

Do what Weedpharma suggests. Also edit your original post to give this thread a proper title. Something like the title of my reply should help others know what this thread is about.