Oscilloscope from a smartphone

 A good oscilloscope is too expensive equipment for an ordinary electronic amateur, for whom soldering microcircuits and repairing electronics (Ex: Diy metal detectors) is only a hobby.

 

 If it is necessary to monitor electrical signals without obtaining extremely accurate results, it is quite possible to do it at home. Such an oscilloscope connects to the smartphone (Oscilloscope from a Android smartphone) screen and operates under the control of a special free application. Its production will be inexpensive and will only take a couple of hours, taking into account the collection of materials.

Materials List:

• 3.5 mm plug from headphones;
• wires;
• heat shrinkage;
• Zener diode 2.2V;
• resistor 2.2K;
• 1K resistor;
• test clip;
• body from the marker;
• furniture carnation.

Assembling the oscilloscope

The figure shows a diagram of the simplest oscilloscope - a probe for a smartphone, which must be repeated. It is very important to use resistors with the same color coding as in the example, as this will allow you to get the maximum sensitivity and accuracy from the device.

The assembly the oscilloscope from android smartphone we should begin by preparing a 3.5 mm mini-jack plug from the headphones. The plastic part is cut off from it, after which 2 wires are soldered as shown in the oscilloscope diagram.

The soldered wires must be additionally secured and insulated. To do this, it will be enough to apply 2 layers of heat shrink tubing.

Next, a single-core wire must be soldered to the head of a small furniture stud. The place of soldering is insulated from above with heat shrinkage. The carnation will act as a positive electrode.

A wire with a stud is inserted into the body of the marker with the rod removed. As a result, the electrode must replace the writing tip of the felt-tip pen. You also need to run the wires from the 3.5mm jack into the punched hole in the back cap of the marker.

Next, you need to connect in parallel and solder the Zener diode with a 1K resistor. A 2.2K resistor is soldered to them according to the device diagram.

A side hole is made in the body of the marker closer to the writing part. A separate wire is threaded into it, the other end of which comes out of the back of the felt-tip pen.

A Zener diode with a 1K resistor is soldered to the output wiring. Also, you need to connect the power cable from the 3.5 mm jack to them. It is important to observe the polarity as shown in the diagram. The second core from the mini-jack is soldered to a 2.2K resistor.

The studded wire must be connected to the remaining end of the 2.2K resistor. All connections are shrink-protected. After that, the resistors and Zener diode must be hidden in the body of the marker, covering it with the back cap.
After that, the hardware of the device is completely ready.

Next, you need to install the Oscilloscope Pro 2 application on your smartphone. The oscilloscope is connected to the phone and can be used for its intended purpose under the control of this program. Its test clip is used as ground, and the stud electrode on the marker is a plus. The application, in conjunction with a home-made device, allows you to set trigger thresholds, view the waveform on the display, and much more.

Watch the video demonstration

Original post: here