SMARTPHONE TESTER

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In this article I will tell you how to make a tester from a smartphone for dialing electrical circuits for an open or short circuit. In fact, I’ll make a prefix for a cell phone (rather, even an adapter with probes), with which you can make measurements. Its circuit is incredibly simple and contains one resistor.

This craft can be useful to you if your working multimeter is broken. Or you do not want to take it with you. Personally, I made such an adapter prefix and threw it into the glove compartment of the car. Now, when I need to ring a light bulb, a fuse or something else, then I take out the probes and connect to the phone.

What features does the tester from a smartphone give?

Using such a tester, you can:

- Ring 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 need: a connector from the old headset "jack" 3.5 mm, for your smartphone, respectively. The resistor is 2.2 kOhm, but if not, you can take another, in the range of 2 - 3 kOhm, though the resistance will not be measured exactly. And the probes are homemade or from a burnt tester. Well, and accordingly, a phone with ANDROID system.

Adapter adapter circuit

Pinout of the headset connector.

We will send a signal from the probes to the microphone input.

Everything can be done by hinged mounting, soldering the resistor to the plug, soldering the wires and pour the whole thing with hot glue. Or make a separate unit with a bifurcation under the probes, put on heat shrink and blow. In extreme cases, 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.
We launch the application and connect the adapter. Everything should work. If you close the probes, you will hear a beep, then everything is fine and you can use it.
Zeros are initially shown:

And when you close the probes with each other, such a word appears and the phone squeaks.

Caution when using the tester

This tester can not measure the circuit where there is voltage! Since your smartphone may fail. Also note that in some circuits there may be residual voltage on the capacitors of the device, which will also be dangerous for a smartphone.
A thing is sometimes very necessary and fit in the household.
Smartphones have long entered our lives and are finding more and more use.