I know it’s an old thread but I checked my ACS712’s with 3.3V and they don’t appear to work. I started with 5V on a Leonardo and it was fine but when you drop down to the Leonardo’s 3.3V the LED lights on the ACS712 board but doesn’t appear to give any data.
I checked the datasheets for the voltage drop on the board but couldn’t find it. When running at 5V if you put a meter between the data pin on the ACS712 and GND you will get around 3V. This is from an actual Leonardo voltage, per the meter, of 5.07V.
I find that the 5V pin on the WeMos is generally around 4.8V and the ACS712 data pin to GND is around 2.4V. This is all well within the 3.3V to 5.0V tolerance of the WeMos data pins, depending which literature you read.
So providing you are not working with a single WeMos and have a 6 week lead time for a replacement then it should be fine to use the 5V ACS712 with the WeMos.
We have had one running for 24 hours and all is fine.
Depending what libraries you use and whether you are reading AC or DC you might find some strange behaviour. Like it’s recommended you boot the device with no current connected to the ACS712. That’s OK if you are just checking a few devices in your property but not feasible for whole house metering.
The other think some of the guides mention is “current leak” whatever that is.
In my project it reads the sensor every second and only prints to Serial Monitor if it detects a current.
Over the last 9 hours (32400 readings) it has detected a current 6 times when the connected device is OFF. So 99.98% accurate as far as detecting the current but I need to do much more testing to check the actually accuracy of the Amps it reports.
@Gunner and @wanek what’s all this current leak about?