Introduction: Continuity Tester (Using Android Phone)

Picture of Continuity Tester (Using Android Phone)

Continuity tester using android phone


1.Android Phone

2. 3.5mm jack or old headphone with mic

3. wire (multimeter probes is better)


Step 1: Cut the Headphone

Picture of  Cut the Headphone

Step 2: Find the MIC and GND Wires

Picture of Find the MIC and GND Wires

Step 3: Connect 3K Resistor Parallel to the MIC and GND

Picture of  Connect 3K Resistor Parallel to the MIC and GND

Connect 3K resistor parallel to the MIC and GND and connect the probes wire and solder it.

Step 4: Finally Insulate the Wires

Picture of Finally Insulate the Wires

Step 5: Install Application to the Phone

Picture of Install Application to the Phone

click to install app

Step 6: Testing.

Picture of  Testing.

click here to see the video

Step 7: Don't Check Charged Components

Picture of Don't Check Charged Components


ara (author)2016-06-01

How do you read the voltage on microfone input?

topstarcreations (author)ara2016-06-01

using multimeter

ara (author)topstarcreations2016-06-01

Nice joke! How do you read from Android, from your cell phone? I don't think that your cell phone display messages based on multimeter measuring. You know what i mean. Apologise for my english.

topstarcreations (author)ara2016-06-01

Use the mic key event .

ara (author)topstarcreations2016-06-01

I'm a very beginner. I need just to find how to do it - few lines of code, in my opinion. I plan to use this in an educational program, using Rfo basic - don't have other Android programming knowledge. This is my last message. If you really want to help me, I thank you in advance. Sorry for inconvenience.

topstarcreations (author)ara2016-06-01

package com.topstarcreations.continuitytestersample;


import android.os.Bundle;

import android.view.KeyEvent;

import android.widget.TextView;

public class MainActivity extends Activity {

TextView valueChange;


protected void onCreate(Bundle savedInstanceState) {



valueChange = (TextView)findViewById(;



public boolean onKeyDown(int keyCode, KeyEvent event) {

switch (keyCode) {




return true;


return super.onKeyDown(keyCode, event);



public boolean onKeyUp(int keyCode, KeyEvent event) {

switch (keyCode) {




return true;


return super.onKeyUp(keyCode, event);


// catches the long press button event (longer than 2 seconds)


public boolean onKeyLongPress(int keyCode, KeyEvent event) {

return true;



ara (author)topstarcreations2016-06-01

Many thanks!

topstarcreations made it! (author)ara2016-06-01

This is the Output

topstarcreations (author)ara2016-06-01


<RelativeLayout xmlns:android=""








tools:context=".MainActivity" >










SaidovB (author)2016-05-29

aahh good idea but how to connect them i have this 3.3 mm jack like you exactly but i dont know what the color that i should connect with 3k resistoris

topstarcreations made it! (author)SaidovB2016-05-30

Use GOLD and RED.

topstarcreations made it! (author)SaidovB2016-05-30

Use GOLD and RED.

topstarcreations made it! (author)SaidovB2016-05-30

Use GOLD and RED.

stateit (author)2016-05-22

What fusing on the leads should I use to protect the phone against inadvertently placing across mains voltage?

tsaltzman (author)stateit2016-05-29

if you don't know for 100% whether or not what you're working on is hot or not, than you shouldn't be working on it bro.

topstarcreations (author)stateit2016-05-23

Don't check the charged components. no fusing.

TFOzkorucuklu (author)2016-05-29

Cool project. I really want to do but I can't do it now, because my phone had died. :/

V4NZ777 (author)TFOzkorucuklu2016-05-29

you probably tested a condutor with voltage

BuhlMan (author)2016-05-29

Not a bad idea but as a technician in my past trade and current hobby, I will always relay on my trusted Fluke meters. Perhaps Fluke will come out with one (unless they one already)

eagas (author)BuhlMan2016-05-29

They do, although it is a Bluetooth interface for the 287/289 series multimeter. The actual measurement is done by the multimeter and it is sent to the phone via the accessory. Just for the sake of it, I own a 289 and I just love it, after a 179 and 115 series. If not the best portable meters surely in the top three.

Mjtrinihobby (author)2016-05-22

I love this instructable. I can't wait for full multimeter modules to be available for smartphones.

ironsmiter (author)Mjtrinihobby2016-05-24

something like this ?

I have multimeters in just about every tool box, and car (at least 6 or 7, spread about), but my smartphone is almost always on my hip. Between datalogging, and reduction in size, I am right there with you, in the "can't wait" group.

Mjtrinihobby (author)ironsmiter2016-05-24


thank you sir.

DIY Hacks and How Tos (author)2016-05-22

Great idea! Having a continuity tester in your phone is much better than having to carrying around a multimeter all the time.

thank you sir.

ccray1954 (author)2016-05-23

what watt or volts are the 3k ohm resistor?

across the resistance below 0.5V

ccray1954 (author)2016-05-23

i like this and need one for my ground to antenna checking continuity...excellent might try to make myself...

Antzy Carmasaic (author)2016-05-22

Love the idea. Simple and easy to use. Do add a warning to remove any power from the circuit you are testing and make sure all capacitors are discharged, as your costly phone is at stake.

Thanks.. yes you are right.

I will surely add a warning.

About This Instructable




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