• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Current Meter

Not open for further replies.


New Member
Hi all.

I've built the circuit as attached, here is the rundown:

- Live current flows from IP+ through IP- of the ACS712.
- VOUT7 of the ACS712 sends Voltage (~5V max) based on a linear graph.
- PIC will perform calculation based on the linear graph and will send result to LCD.
- Tact switch at right is to enter Calibration Mode, where when clicked, it sends a high to the PIC (where programming-wise, it will then call a function called Calibration to perform).
- Tact switches at the left are to perform the calibration (move left, increase value, move right, decrease value).

However, I'm not sure if the circuit is perfect:

1) The four tact switches on the left, they are supposed to be wired as such, right? Their purpose is to calibrate the display value, where when clicked, it sends a high to the PIC and the PIC performs its calculation accordingly (calls a function and performs it, then returns).

2) The tact switch on the right is to enter calibration mode. It's wired correctly, right?

3) Is there any other noticeable errors?

I know this will take quite some time, so I thank you for spending time on my concern.



Well-Known Member
Most Helpful Member
The circuit looks correct to me.

The diagram often implies connections rather than with lines. For example, X1 on S2 is connected to X1 on R3.

R3 to R7 are needed as pull-down resistors for S2 - S6.

However, the functioning of the circuit is dependent on the program in the PIC. A lot of the design work is programming. That isn't shown in your post so I can't comment on it.


New Member
Hi Viann,

I don't know about programming MCUs, but what I've seen so far programming should be easier by pulling digital I/O pins up and activate them by closing buttons to ground.

Use 10K pullup resistors for each digital I/O.

Also omit the junctions at pins 2 and 3 of the ACS712 as well as on pins 1, 2, 11, 13, 14 and 31 of the MCU. They are confusing.

Last edited:
Not open for further replies.

EE World Online Articles