ACS715 Current Sensor Difficulty

I recently purchased several (5) ACS715 current sensing units for use in a project that I’m working on, and I’ve been having difficulty getting any meaningful data out of them. My project involves a DC generator connected to a bike, which is then connected to a series of light bulbs. I wanted to measure the amount of current going through the system, so I connected a AC715 sensor in series with my circuit. When I supply the sensor with 5V, it outputs a value of 0.5 V. When I pedal the bike, even as fast as I can, I can only reach a value of 0.503 or 0.504 V. I can’t really figure out why I’m not reaching the ~133 mV/A resolution.

My system is setup as follows:
(1) x Arduino Uno Board
(1) x ACS715 Current Sensor

I have connected the Arduino +5 V to the Vcc connector on the sensor. I’ve connected the ground on both the arduino and on the sensor together. I’ve connected the out on the sensor to one of the Arduino’s analog inputs.

I’ve tried a few things:

  • I have tested this system using two separate ACS 715 current sensors
  • I am sure that the sensor is connected in the proper direction. I tried both configurations, but the correct orientation of the sensor yields up to 0.504 V, while the incorrect orientation yields around 0.499 V
  • I have measured the amount of current I expect to be sensing, and it is over 10 A (which is the highest my multimeter can read)
  • I have measured the output voltage using only my multimeter (connected between the out pin of the sensor and the Arduino ground), and I receive the same results
  • I have confirmed that the Arduino is producing a 5 V output

I have reviewed several other posts regarding current sensors, but I didn’t find any that corresponded to my particular issue. If I’ve missed one, I apologize for re-posting.



I am sorry to hear you are having trouble with your current sensors. Could you post a picture of your setup showing how you have everything connected?

- Kevin

The system isn’t really fully assembled at this point, but these are the best pictures I could get:

They formatted kinda weird when I uploaded them here, so I put them in a imgur album.

Have you verified the connectivity of your connections, and did you make sure that all of the current is flowing through the sensor? (There should be no alternate paths for the current to take, so that if you disconnect the sensor, no current should flow.) If you connect your multimeter in line with the sensor, do you measure the 10+ A that you expect?

It is difficult to see where the current path wires go and how they eventually connect to your generator. Do you have a diagram that shows your entire setup?

- Kevin


I’ve verified that all of my connections are sound, and I tested to make sure that the 10+ A goes through the sensor by connected my multimeter in series with the sensor. If I disconnect the sensor, no current flows through my circuit.

I drew up a quick schematic of my system, and I took a few more pictures. In the pictures you’ll see a whole mess of wires for other lightbulbs, but they are all currently disconnected, so I didn’t include them on the schematic.

I appreciate your help.

Your setup looks okay in general, although your OUT, Vcc, and GND connections are kind of exposed; it would be a good idea to trim the wires or insulate them. Unfortunately, it sounds like your current sensor might be broken. I am not sure what went wrong with it, but if you email us directly with your order information and reference this forum topic, we can at least offer you a discount on a replacement.

- Kevin