Smartphone tester

In this article, I will tell you how to make a tester out of a smartphone to test electrical circuits for open circuits or short circuits. In fact, I will make an attachment for a cell phone (more likely even an adapter with probes), with which you can take measurements. Its circuit is incredibly simple and contains one resistor.

This craft may come in handy if your worker is broken. multimeter. Or you don't want to take it with you. Personally, I made such an adapter-attachment and threw it in the glove compartment of the car. Now, when I need to ring a light bulb, fuse or something else, I take out the probes and connect them to the phone.

What capabilities does a smartphone tester provide?

With this tester you can:

• - Check the circuit for an open or short circuit.
  
• - Find out the approximate resistance value (0-70 Ohm).
  
• - The smartphone makes a sound when continuity is detected.

We will need: a 3.5 mm jack from an old headset, suitable for your smartphone, respectively. The resistor is 2.2 kOhm, but if not, you can take another one, in the range of 2 - 3 kOhm, although the resistance will not be measured so accurately.And the probes are homemade or from a burnt tester. Well, accordingly, a phone with the ANDROID system.

Adapter-attachment diagram

Pinout of headset jack pins.

We will feed the signal from the probes to the microphone input.

Everything can be done by surface mounting by soldering a resistor to the plug, soldering the wires and filling the whole thing with hot glue. Or make a separate unit with a split for the probes, put on heat shrink and blow it off. As a last resort, use electrical tape. 15 minutes of work, no more...

Smartphone app

After the adapter is soldered, download the application to Google Play (active link to the application) and install.
Launch the application and connect the adapter. Everything should work. If you close the probes, you will hear a beep, which means everything is fine and you can use it.
Initially zeros are shown:

And when you close the probes together, this word appears and the phone beeps.

Caution when using the tester

This tester cannot measure circuits where there is voltage! Because your smartphone may fail. Also keep in mind that in some circuits there may be residual voltage on the device’s capacitors, which will also be dangerous for the smartphone.
Sometimes a thing is very necessary and useful in the household.
Smartphones have long been part of our lives and are being used more and more.

Watch the video on how to make a tester from a smartphone