Based on computer audio devices, virtual measuring devices are created. Such as virtual frequency counter, virtual oscilloscope, virtual spectrometer. The devices are connected to the microphone or line input of the sound card, the signal is measured by the ADC chip. The frequency (width) of the signal depends on the sampling rate of the audio card, most often 22kHz. Several tool programs were considered Frequency Counter 1.01, Simple Audio Spectrum Analyzer, Music Tuner v1.2 and OSZI v1.0
Rice. 1. Microphone with High Definition Audio support
In the settings after "turning on" the gain levels of the input signal are set for the microphone or line input: first, the minimum values, then increasing the levels to achieve the optimal value. Strong signal amplification causes distortion and overload. The bit depth and sampling rates must be chosen as high as possible. In my case, the bit depth is 16 bits, the sampling rate is 96000 Hz (Fig. 1 i.e. The maximum frequency per channel is 48 kHz. To match the input signal levels, you need a small adapter in fig. 2. The adapter filters and smoothes the received signal. On the audio jack 3.5mm pin 1, the measured signal is supplied. It is necessary to control the input signal voltage - the input voltage is safe for this adapter up to 9V, the optimal range is from 1 to 2.5V. For high voltage requires the development of a different adapter circuit, "transformer" options. The circuit is not galvanically isolated, so observe the polarity, minus to minus, plus to the side with the capacitor.
Rice. 2. Adapter scheme for virtual: frequency counter; oscilloscope; spectrometer
Virtual Devices
In general, anyone can create their own virtual instruments based on a PC. The only limitation of such devices is the low sampling rate of the sound card, due to which digital measurements end at 48kHz. IMHO for any radio amateur in simple tasks such virtual assistants will come in handy.
Quite often lately, instead of making, for example, an oscilloscope from a computer, many people prefer to simply buy a digital USB oscilloscope. However, looking at the market, you can understand that in fact the cost of budget oscilloscopes starts at about $ 250. And more serious equipment does have a price several times higher.
It is for those people who are not satisfied with such a cost that it is more relevant to make an oscilloscope from a computer, especially since it allows you to solve a large number of tasks.
What should be used?
One of the best options is the Osci program, which has an interface similar to a standard oscilloscope: there is a standard grid on the screen, with which you can independently measure the duration, or the amplitude.
Among the shortcomings of this utility, it can be noted that it works somewhat unstable. In the course of its work, the program may sometimes freeze, and in order to reset it later, you will need to use a specialized Task Manager. However, all this is offset by the fact that the utility has a familiar interface, is quite easy to use, and also has a fairly large number of functions that allow you to make a full-fledged oscilloscope from a computer.
On a note
It should be noted right away that these programs include a specialized low-frequency generator, but its use is highly discouraged, as it tries to completely independently regulate the operation of the audio card driver, which can cause irreversible sound muting. If you try to use it, make sure that you have your own restore point or the ability to make a backup operating system. The best option on how to make an oscilloscope out of a computer with your own hands is to download a normal generator, which is located in the "Additional Materials".
"Vanguard"
Avangard is a domestic utility that does not have a standard and familiar measuring grid, and also has a screen that is too large for taking screenshots, but at the same time provides the ability to use the built-in amplitude voltmeter, as well as a frequency counter. This allows you to partially compensate for the disadvantages that were mentioned above.
Having made such an oscilloscope from a computer with your own hands, you may encounter the following: at low signal levels, both the frequency counter and the voltmeter can greatly distort the results, however, for beginner radio amateurs who are not used to perceiving diagrams in volts or milliseconds per division, this utility will quite acceptable. Its other useful feature is that it is possible to carry out a completely independent calibration of the two existing scales of the built-in voltmeter.
How will it be used?
Since the input circuits of the audio card have a specialized coupling capacitor, the computer can only be used as an oscilloscope with a closed input. That is, only the variable component of the signal will be observed on the screen, however, with some skill, using these utilities, it will also be possible to measure the level of the constant component. This is quite relevant if, for example, the countdown time of the multimeter does not make it possible to fix a certain amplitude value of the voltage across the capacitor, which is charged through a large resistor.
The lower voltage limit is limited by the noise and background levels and is approximately 1 mV. The upper limit is limited only by the parameters of the divider and can even reach several hundred volts. The frequency range is directly limited by the capabilities of the audio card itself and for budget devices is approximately from 0.1 Hz to 20 kHz.
Of course, in this case, a relatively primitive device is considered. But if you do not have the opportunity, for example, to use a USB oscilloscope (prefix to a computer), then in this case its use is quite optimal.
Such a device can help you repair various audio equipment, and can also be used exclusively for educational purposes, especially if you supplement it with a virtual bass generator. In addition, the oscilloscope program for a computer will allow you to save a plot to illustrate certain material or for the purpose of posting it on the Internet.
Wiring diagram
If you need a prefix to a computer (an oscilloscope), then making it will be a little more difficult. At the moment, on the Internet you can find a fairly large number various schemes such devices, and to build, for example, a two-channel oscilloscope, you will need to duplicate them. The use of the second channel is often relevant if you need to compare two signals or if a set-top box to a computer (oscilloscope) will also be used with an external synchronization connection.
In the vast majority of cases, the circuits are extremely simple, but in this way you can independently provide a fairly wide range of voltages available for measurement, while using the minimum number of radio components. In this case, the attenuator, which is built according to the classical scheme, would require you to use specialized high-megaohm resistors, and its input resistance would constantly change in the event of a range switch. For this reason, you would experience certain limitations in using standard oscilloscope cables, which are rated for an input impedance of no more than 1 mΩ.
We provide security
In order for the line input of the audio card to be protected from the possibility of accidental high voltage, specialized zener diodes can be installed in parallel.
With the help of resistors, you can limit the current of the zener diodes. For example, if you are going to use your computer oscilloscope (generator) to measure a voltage of about 1000 volts, then in this case you can use two one-watt or one two-watt resistor as a resistor. They differ among themselves not only in their power, but also in what voltage in them is the maximum allowable. It is also worth noting the fact that in this case you will also need a capacitor, the maximum allowable value for which is 1000 volts.
Attention!
It is often necessary to initially look at the variable component of a relatively small amplitude, which, in this case, may differ in a rather large constant component. In this case, on the screen of an oscilloscope with a closed input, there may be a situation where you will not see anything but the variable component of the voltage.
Choosing voltage divider resistors
Due to the fact that quite often modern radio amateurs experience certain difficulties in order to find precision resistors, it often happens that you have to use standard devices for general use, which will need to be adjusted with maximum accuracy, since otherwise it would not be possible to make an oscilloscope from a computer. will come out.
High-precision resistors in the vast majority of cases are several times more expensive than conventional ones. At the same time, today they are most often sold at once in 100 pieces, and therefore their acquisition cannot always be called expedient.
Trimmers
In this case, each divider arm is made up of two resistors, one of which is constant, while the second is trimmer. The disadvantage of this option is its bulkiness, however, the accuracy is limited only by what available parameters the measuring device has.
We select resistors
The second option to make a computer in the role of an oscilloscope is to pick up pairs of resistors. Accuracy in this case is ensured due to the fact that pairs of resistors from two sets with a sufficiently large spread are used. The important thing here is to first make a careful measurement of all devices, and then choose pairs whose sum of resistances is the most suitable for the circuit you are performing.
It is worth noting that this particular method was used on an industrial scale in order to adjust the divider resistors for the legendary TL-4 device. Before you make an oscilloscope from a computer with your own hands, you need to study the possible disadvantages of such a device. First of all, we can note the complexity, as well as the need to use a large number of resistors. After all, the longer the list of devices you use, the higher the final accuracy of the measurements will be.
Resistor Fitting
It is worth noting that fitting resistors by removing part of the film is sometimes used today even in modern industry, that is, an oscilloscope is often made from a computer (USB or some other) in this way.
However, it should be noted right away that if you are going to adjust high-resistance resistors, then in this case the resistive film should in no case be cut through. The thing is that in such devices it is applied to a cylindrical surface in the form of a spiral, therefore, it is necessary to make a cut with extreme caution in order to exclude the possibility of breaking the chain.
If you make an oscilloscope from a computer with your own hands, then in order to adjust the resistors at home, you just need to use the simplest sandpaper "zero".
- Initially, the resistor with a known lower resistance must be carefully removed from the protective layer of paint.
- After that, you should solder the resistor to the ends, which will be glued to the multimeter. By performing careful movements with sandpaper, the resistance values \u200b\u200bof the resistor are brought to a normal value.
- Now that the resistor has been finally adjusted, the cut must be covered with an additional layer of specialized protective varnish or glue.
At the moment, this method can be called the simplest and fastest, but at the same time it allows you to get good results, which makes it optimal for work at home.
What should be taken into account?
There are a few rules that you need to follow in any case if you are going to carry out such work:
- The computer you are using must be properly grounded.
- Under no circumstances should you plug a ground wire into the outlet. It connects through a specialized line-in connector housing to the system unit housing. In this case, regardless of whether you fall into zero or into phase, you will not have a short circuit.
In other words, only a wire connected to a resistor, which is located in the adapter circuit and has a rating of 1 megohm, can be plugged into the outlet. If you try to plug in the cable that connects to the case, then in almost all cases this leads to the most unpleasant consequences.
If you will use the Avangard oscilloscope, then in this case, during the calibration process, you should select the scale of the voltmeter "12.5". After you see the mains voltage on your screen, you will need to enter the value 311 into the calibration window. It is worth noting that the voltmeter should then show you a result in the form of 311 mV or close to it.
Among other things, do not forget that the voltage shape in modern electrical networks is different from sinusoidal, since today electrical appliances are produced with switching power supplies. It is for this reason that you will need to focus not just on the visible curve, but also on its sinusoidal continuation.
Basic oscilloscope parameters | |
Parameter | Meaning |
Type | digital |
Execution | console for PC |
Bandwidth, MHz | 20 |
Main parameters of the generator | |
Parameter | Meaning |
Execution | console for PC |
Basic parameters of the frequency meter (frequency standard, comparator) | |
Parameter | Meaning |
Purpose | frequency meter |
Execution | console for PC |
Maximum frequency, MHz | 250.00 |
The PV6501 USB oscilloscope is designed to create a workplace for a radio amateur, adjuster, developer based on a personal computer or laptop. In addition to the oscilloscope, the prefix works in the generator and frequency counter modes.
USB Oscilloscope PV6501 is designed to create a workplace for a radio amateur, adjuster, developer based on a personal computer or laptop. In addition to the oscilloscope, the prefix works ...
Detailed description
Characteristics
- High sampling rate. Allows you to reliably display the signal up to 20 MHz.
- The full feel of working with a conventional analog oscilloscope. Instant response to user actions. Speed dialing and display of readings.
- Intuitive interface. Simple and logical controls. You don't even have to read the instructions - just one glance at the screen is enough to get started with the PV6501 for the first time.
- Built-in generator up to 10 MHz. It is convenient to use for removing the frequency response.
- Accurate frequency counter. 7 significant digits are displayed.
- Convenient installation. The program can be placed anywhere, even run from a CD. During installation, the system registry is not updated, only the standard USB driver is installed in the system.
- Galvanic decoupling. Your computer is protected from the measured circuit. Noise from the computer's power supply will not interfere with measurements.
- Dimensions: 165 x 80 x 30 mm
- Weight: 150 g
Equipment
- Oscilloscope PV6501
- CD-ROM (contains the program, drivers and instructions).
- USB-AB cable 1.8 m.
Possibilities
- Oscilloscope
- Marker measurements, auto measurements of signal parameters, signal scaling (time magnifier), recording waveforms to a file (in graphical or text form).
- Glitch registration mode and "Peak detect" aliasing suppression.
- Open/closed entry mode. (For correct measurements with closed input, the value of the DC component must be between -20 and +20 V.)
- Synchronization
- Internal and external synchronization.
- On the front / cut of the input signal.
- Waiting (starting a sweep when the synchronization condition is met). Automatic (sweep starts automatically regardless of the trigger condition). A single or multiple launch of a sweep is possible.
- Generator
- Operation based on Direct Digital Frequency Synthesis (DDS).
- Frequency sweep mode synchronously with the sweep of the oscilloscope (GKCh).
- Electronic counting frequency meter
- The principle of operation is based on the simultaneous measurement of the frequency and period of the signal over a time interval of 1 sec.
Specifications
- Oscilloscope:
- maximum sampling rate 100 MHz
- ADC bit depth 8 bit
- 20 MHz vertical amplifier bandwidth
- input impedance 1 MΩ
- input capacitance 20 pF
- maximum allowable input voltage (sum of constant and variable components) 150 V
- open/closed input mode For correct measurements with a closed input, the value of the DC component must be from -20 to +20 V.
- memory capacity 8000 readings
- vertical deviation coefficients 50 mV/div...2 V/div. (6 calibrated values in steps of 1-2-5)
- horizontal sweep coefficients 50 ns/div...2 s/div. (24 calibrated values in steps of 1-2-5). On sweeps 100 ms / div ... 2 s / div. the continuous cyclic mode (without dead zone) with continuous visualization is switched on.
- input impedance of genlock input 1 MΩ
- input capacitance 20 pF
- 1.3V external trigger level (Schmitt trigger with 1.0V and 1.6V thresholds)
- maximum allowable voltage at the input of external synchronization (the sum of the constant and variable components) 150 V
- Synchronization:
- adjustable level ±4 divisions
- adjustable prefetch length 0...9 divisions
- configurable sync noise reduction level (hysteresis) 0 div...2 div
- configurable edge/slope number causing synchronization 1...255
- Generator:
- generated frequency range 0.1 Hz...10 MHz
- sample rate 100 MHz
- DAC 9 bit
- phase accumulator bit length 40 bit
- frequency setting step 5 significant digits (but not less than 0.1 Hz)
- pulse generator mode with arbitrary duty cycle in the range of 10 ns ... 1 s
- amplitude adjustment range 1V...4V (P-P-Value: Generator output is DC = 1/2 P-P value.)
- amplitude adjustment step 8 mV
- output impedance 50 ohm
- Electronic counting frequency meter:
- range of measured frequencies from the oscilloscope input 2 Hz ... 30 MHz, from the external synchronization input up to 250 MHz
- sensitivity from the oscilloscope input is not less than 20 mV,
- from the external synchronization input - Schmitt trigger with thresholds of 1.0 V and 1.6 V
- when working from the input of the oscilloscope, the frequency meter operates according to the synchronization level, while it is possible to adjust the noise reduction level (hysteresis) 0 div ... 2 div, x is the vertical deviation coefficient of the oscilloscope
- word length 7 significant digits
terms of Use
- The maximum voltage at the input of the oscilloscope and external synchronization is +-150 V. The ambient temperature is +10..+30°С. Relative humidity no more than 75% at 20 °C.
Minimum computer requirements:
- Pentium I - 166 Mhz, 64 RAM, Win 98, USB_1.1, 5 V, 500 mA.
Oscilloscope Probes - HP-9060
Manufacturer:
To comment on materials from the site and get full access to our forum, you need to register . |
- The fact is that it is painfully pleasant and beautiful toy turns out. Now instead of laptops - netbooks have gone (Asus on Celeron is cheaper than $ 250 and less weight (1 kg) and size (screen 9 inches)). A netbook is also a reference, and you can quickly access the Internet if anything. Powered by batteries. And there are plenty of such consoles (the leading manufacturer Pico is the most expensive). They are also voltmeters and spectrum analyzers. Some cheap models come with open source software in Pascal or C and you can change the interface (menu, beam color, automation) to your taste. Pico range
- I think that the device should be a device and not a place of entertainment, and these lotions have many shortcomings.
- Let the device be a device, but you can’t drag the entire listed fleet of devices with you, and not only the park - individual devices too, and some simply cannot afford. So such a portable "probe laboratory" is very promising in addition to the aforementioned convenience. Every berry has its time;)
- Devices from Pico are damn expensive indeed. The parameters are not bad. For example, I don’t make any special demands from such a “gadget”, it would not hurt me (I almost always have a laptop with me), but not for such prices as Pico. You can, of course, look on e-bay ...
- on ebay
- All the same, universality is the reverse side of specialization. I had something similar to try out. Despite the small size of my Maxmedia (photo in the section Conversations on a free topic-About Ivan Tsarevich and Toad), I did not find the use of such a device convenient. But the taste and color, as they say ...
- Let's then, as cool specialists, we will measure current, voltage (separately constant and variable), resistance with separate devices. :)
- No need to distort and bring to the point of absurdity. The size of any multimeter is not commensurate with the table space offered. Let's add here the possible burning of something in the laptop with a soldering iron (well, if not the screen). Everyone thinks, I’m really neat, I won’t burn anything, that only others do it. The cost of this + the cost of a laptop (not everyone has enough space at home) pulls on a good digital storage oscilloscope. I repeat, I tried the Aktakom craft and I didn’t like it all. And when you grow up to some serious tasks, then you may just have to measure the values with your specialized instruments.
- A joke is not a joke. Okay, I'm not kidding if you react like that. Give better numbers. A "good digital storage oscilloscope" is very expensive (like a car). I mean not a stolen device. Everything that I wrote I meant unstolen. Give prices with links (at least for a bad digital oscilloscope). I'm curious to see your calculations. I don't fit. So far, I only agree with your argument about burning with a soldering iron. The spectrum analyzers I worked with were carted around and cost $50-100,000. I will never buy this. And I don't want to keep it at home. I look from the side of private practice, not a company that can afford a lot.
- It depends, of course, what is meant by the word good, it all depends on the task. And depending on which car to keep in mind. For me, a good solution turned out to be 25 MHz 2 channels UNIT-T 14000 rubles. 100 MHz x 2 channels already 30,000 rubles. Prices last summer. Maybe these devices will not satisfy you, I don’t know your tasks, but I can confidently predict that even for 30,000 rubles a worthwhile car (which will drive more than break) cannot be purchased for this amount. Aktacom has similar devices - I looked at the ELIX mailing list. For studies of UPS, MCU, TV nodes on CRT, it’s quite even. If your tasks go beyond this circle, alas. GKCH were very expensive, high-precision instruments. But these should be used at work. Or, if your business is organized and it successfully makes a profit, crush the damned toad, no matter how much the device costs. Because he needs to make money privately. Although here we argue about tastes, buy yourself this prefix, share your operating experience.
- I emphasize once again that these consoles are not only an oscilloscope, but also a bunch of other devices, including, as a rule, a spectrum analyzer. So if you count money, then you need to add up the cost of several devices, and not just an oscilloscope. Apparently, it is useless for us to discuss prices - it depends a lot on the country. I can also buy a car that will still be passable for several years for $ 1000 or even cheaper. I had to give my 14-year-old Buick, still quite on track, for $ 500 4 years ago, since it was no longer worth even then. The machine is a consumer product that everyone needs and therefore is cheap, an oscilloscope, etc. is a professional device - limited demand and therefore expensive.
- Judging by the parameters - this device is more like an amateur radio. The price, however, is quite professional ... We should also not forget about software. Some experience with such devices allows me to say that, as a rule, the software for them is also made at an amateur level. Unfortunately... :(God forbid that this particular device was an exception...
- Here is this lotion and adapt to the handheld.
- And I will probably order a similar device (I will also look at the parameters) on e-bay. Purely for the "home workshop", when designing their devices and nothing more. I'll unsubscribe later...
- Vadzz, read here
- http://www.masteram.biz/ru/Measuring...Oscilloscopes/ Here is a more solid office and, accordingly, more expensive than the UNIT-T I mentioned. For $ 1000 you can buy exactly a CARINGLY driving car, and not normally (that is, replacing only consumables and liquids), although everyone has their own measure of tolerance and depends on external influences (life) on the control system (brain). I never needed a spectrum analyzer, as I was engaged in tasks that were not related to the need for such an instrument. The oscillating frequency generator (colloquially "acechometer") used 1 time in my life. For what purposes do you, slavar1, use the spectrum analyzer?
- LEAS, you wrote that "but I can confidently predict that even for 30,000 rubles a worthwhile car (which will drive more than break) cannot be purchased for this amount." I answered this. We mainly used spectrum analyzers to measure the frequency characteristics of piezoelectric transducers, of which there were hundreds of varieties in different frequency ranges (from subsonic frequencies to 15 kHz). More often in infra. For a radio amateur at home, of course, it can come in handy rarely - only for those who constantly rivet amplifiers and filters, but it can be useful in combating interference.
- In modern ZyfZapOscil there is a frequency meter and cursor measurements, etc. This is what I wanted to emphasize. Everything else is there. And I already wrote that the dispute over this is a dispute about the taste of oysters, but I already ate them! I didn’t like it, so if Vaddz buys it, he will share his impressions.
- Hello! I specialize in the repair of car alarms operating at a frequency of 433 megahertz, I need to see the encoding and the modulation process itself, remember and reproduce these signals. The presence of a generator, a frequency meter, a voltmeter and an oscilloscope is a must for me! What device do you recommend? And this device would have enough processing speed, etc. I would like to know the specific model and price!:eek:
- An oscilloscope-multimeter-frequency counter can replace this .... It will be more difficult with a generator if you really want to generate complex signals at 433 MHz ...
Technology does not stand still, and keeping up with them is not always easy. There are new items that I would like to understand in more detail. This is especially true of the various ones that allow you to assemble almost any simple device step by step. Now among them are Arduino boards with their clones, and Chinese microprocessor computers, and ready-made solutions that already come with software on board.
However, to work with all of the above range of interesting new products, as well as to repair digital equipment, you need an expensive high-precision tool. Among such equipment is an oscilloscope that allows you to read frequency readings and carry out diagnostics. Often, its cost is quite high, and novice experimenters cannot afford such an expensive purchase. Here a solution comes to the rescue, which appeared on many amateur radio forums almost immediately after the appearance of tablets on the Android system. Its essence is to make an oscilloscope from a tablet at minimal cost, without making any modifications or modifications to your gadget, and also eliminating the risk of damaging it.
What is an oscilloscope
Oscilloscope - as a device for measuring and tracking frequency fluctuations in electrical network- known since the middle of the last century. All educational and professional laboratories are equipped with these devices, since it is possible to detect some malfunctions or fine-tune the equipment only with its help. It can display information both on the screen and on paper tape. The readings allow you to see the shape of the signal, calculate its frequency and intensity, and as a result determine the source of its occurrence. Modern oscilloscopes allow you to draw three-dimensional color frequency graphs. Today we will focus on a simple version of a standard two-channel oscilloscope and implement it using a prefix to a smartphone or tablet and the corresponding software.
The easiest way to create a pocket oscilloscope
If the measured frequency is in the range of frequencies audible to the human ear, and the signal level does not exceed the standard microphone level, then you can assemble an oscilloscope from an Android tablet with your own hands without any additional modules. To do this, it is enough to disassemble any headset, which must have a microphone. If there is no suitable headset, then you will need to buy a 3.5 mm audio plug with four pins. Before soldering the probes, check the pinout of your gadget's connector, because there are two types of them. The probes must be connected to the pins corresponding to the microphone connection on your device.
Next, you should download software from the "Market" that can measure the frequency at the microphone input and draw a graph based on the received signal. There are quite a few such options. Therefore, if desired, there will be plenty to choose from. As mentioned earlier, no modification of the tablet was required. The oscilloscope will be ready as soon as the application is calibrated.
Pros and cons of the above scheme
The advantages of such a solution can definitely be attributed to the simplicity and low cost of assembly. An old headset or one new jack costs next to nothing, and it only takes a few minutes.
But this scheme has a number of significant drawbacks, namely:
- Small range of measured frequencies (depending on the quality of the audio path of the gadget, it ranges from 30 Hz to 15 kHz).
- Lack of protection for the tablet or smartphone (if you accidentally connect the probes to sections of the circuit with increased voltage, you can, at best, burn the chip responsible for processing the audio signal on your gadget, and at worst, completely disable your smartphone or tablet).
- On very cheap devices, there is a significant error in signal measurement, reaching 10-15 percent. For fine-tuning equipment, such a figure is unacceptable.
Implementation of protection, signal shielding and error reduction
In order to partially protect your device from possible failure, as well as to stabilize the signal and expand the input voltage range, you can use a simple oscilloscope circuit for a tablet, which has been successfully used for assembling devices for a computer for a long time. It uses cheap components, including KS119A zener diodes and two 10 and 100 kOhm resistors. The zener diodes and the first resistor are connected in parallel, and the second, more powerful resistor is used at the input of the circuit in order to expand the maximum possible voltage range. As a result, a large amount of interference disappears, and the voltage rises to 12 V.
Of course, it should be borne in mind that the oscilloscope from the tablet works primarily with sound pulses. Therefore, it is worth taking care of high-quality shielding of both the circuit itself and the probes. If desired, detailed instructions for assembling this circuit can be found on one of the thematic forums.
Software
To work with such a scheme, a program is required that can draw graphs based on the incoming sound signal. Finding it in the "Market" is easy, there are many options. Almost all of them involve additional calibration, so you can achieve the highest possible accuracy, and make a professional oscilloscope from a tablet. Otherwise, these programs perform essentially the same task, so the final choice depends on the required functionality and ease of use.
Homemade set-top box with a Bluetooth module
If a wider frequency range is required, then the above option will not work. Here a new option comes to the rescue - a separate gadget, which is a set-top box with an analog-to-digital converter that provides signal transmission in digital form. In this case, the audio path of a smartphone or tablet is no longer involved, which means that higher measurement accuracy can be achieved. In fact, at this stage they are only a portable display, and all information is collected by a separate device.
You can assemble an oscilloscope from an Android tablet with a wireless module yourself. There is an example on the network when a similar device was implemented back in 2010 using a two-channel analog-to-digital converter created on the basis of the PIC33FJ16GS504 microcontroller, and the LMX9838 Bluetooth module served as a signal transmitter. The device turned out to be quite functional, but difficult to assemble, so for beginners it will be an impossible task to make it. But, if you wish, finding a similar project on the same amateur radio forums is not a problem.
Ready-made options for set-top boxes with Bluetooth
Engineers are not asleep, and, in addition to handicrafts, more and more set-top boxes appear in stores that perform the function of an oscilloscope and transmit a signal via Bluetooth to a smartphone or tablet. An oscilloscope attached to a tablet connected via Bluetooth often has the following main characteristics:
- Measured frequency limit: 1MHz.
- Probe voltage: up to 10 V.
- Action radius: about 10 m.
These characteristics are quite enough for domestic use, and yet in professional activities, sometimes there are cases when this range is sorely lacking, and it is simply unrealistic to implement a larger one with the slow Bluetooth protocol. What is the way out in this situation?
Wi-Fi oscilloscopes
This option of data transmission significantly expands the capabilities of the measuring device. Now the market for oscilloscopes with this type of information exchange between the set-top box and the tablet is gaining momentum due to its demand. Such oscilloscopes are almost as good as professional ones, because without delay they transmit the measured information to the tablet, which immediately displays it as a graph on the screen.
Management is carried out through simple, intuitive menus that copy the setting elements of conventional laboratory devices. In addition, such equipment allows you to record or broadcast in real time everything that happens on the screen, which can be an indispensable tool if you need to ask for advice from a more experienced master located elsewhere.
The characteristics of the oscilloscope for a set-top box with a Wi-Fi connection grow several times compared to previous options. Such oscilloscopes have a measurement range of up to 50 MHz, while they can be modified using a variety of adapters. Often they are equipped with batteries for autonomous power supply, in order to unload as much as possible. workplace from unnecessary wires.
Homemade versions of modern oscilloscope attachments
Of course, there is a surge of various ideas on the forums, with the help of which enthusiasts are trying to fulfill their old dream - to independently assemble an oscilloscope from an Android tablet with a Wi-Fi channel. Some models are successful, others are not. It’s up to you to decide whether to try your luck too and save a few dollars by assembling the device yourself, or to purchase a ready-made version. If you are not confident in your abilities, then it is better not to take risks, so as not to regret the wasted funds later.
Otherwise - welcome to one of the communities of radio amateurs, in which you can be given good advice. Perhaps, later, it is according to your scheme that beginners will assemble their first oscilloscope in their life.
Set-top box software
Often, along with purchased oscilloscopes, set-top boxes come with a disk with a program that you can install on your tablet or smartphone. If there is no such disk in the kit, then carefully study the instructions for the device - most likely, it contains the names of programs compatible with the set-top box and located in the application store.
Also, some of these devices can work not only with devices running the Android operating system, but also with more expensive Apple devices. In this case, the program will definitely be in the AppStore, since there is no other installation option. Having made an oscilloscope from a tablet, do not forget to check the accuracy of the readings and, if necessary, calibrate the device.
USB oscilloscopes
If you don't have a portable device like a tablet, but you do have a laptop or computer, don't worry. You can also make a beautiful one out of them. The simplest option is to connect the probes to the microphone input of the computer in the same way as described at the beginning of the article.
However, given its limitations, this option is not for everyone. In this case, a USB oscilloscope can be used, which will provide the same performance as a set-top box with signal transmission over Wi-Fi. It is worth noting that such devices sometimes work with some tablets that support the technology for connecting external OTG devices. Of course, they also try to make a USB oscilloscope on their own, and quite successfully. At least, a large number of topics on the forums are devoted to this craft.
An oscilloscope is a device that helps to see the dynamics of oscillations. With its help, you can diagnose various breakdowns and obtain the necessary data in radio electronics. In the past, transistorized oscilloscopes were used. These were very bulky devices that were connected exclusively to a built-in or specially designed screen.
Today, devices for taking the main frequency, amplitude characteristics and waveforms are convenient, portable and more compact devices. Often they are performed as a separate set-top box that connects to a computer. This maneuver allows you to remove the monitor from the package, significantly reducing the cost of equipment.
You can see what a classic device looks like by looking at a photo of an oscilloscope in any search engine. At home, you can also mount this device using inexpensive radio components and cases from other equipment for a more presentable look.
How can I get an oscilloscope
Equipment can be obtained in several ways and it all depends solely on the amount of money that can be spent on acquiring equipment or parts.
- Buy a ready-made device in a specialized store or order it online;
- To buy a constructor, for example, sets of radio components, cases, which are sold on Chinese sites, are now very popular;
- Independently assemble a full-fledged portable device;
- Mount only the prefix and probe, and organize the connection to a personal computer.
These options are listed in order of decreasing equipment cost. Buying a ready-made oscilloscope will cost the most, since it is already delivered and working unit with all the necessary functions and settings, and in case of incorrect operation, you can contact the sales center.
The designer includes a simple do-it-yourself oscilloscope circuit, and the price is reduced by paying only the cost of radio components. In this category, it is also necessary to distinguish between more expensive and simple models in terms of configuration and functionality.
Assembling the device yourself according to the available schemes and radio components purchased at different points may not always be cheaper than acquiring a designer, therefore, it is necessary to first evaluate the cost of the idea, its justification.
The cheapest way to get an oscilloscope is to solder only the prefix to it. For the screen, use a computer monitor, and programs for capturing and transforming the received signals can be downloaded from various sources.
Oscilloscope Builder: Model DSO138
Chinese manufacturers have always been famous for their ability to create electronics for professional needs with very limited functionality and for quite a bit of money.
On the one hand, such devices are not able to fully satisfy a number of needs of a person involved in radio electronics in a professional way, however, beginners and lovers of such “toys” will be more than enough.
One of the most popular Chinese-made models such as an oscilloscope designer is the DSO138. First of all, this device has a low cost, and it comes with all the necessary parts and instructions, so there should be no questions about how to make an oscilloscope with your own hands using the documentation included in the kit.
Before installation, you need to familiarize yourself with the contents of the package: board, screen, probe, all the necessary radio components, assembly instructions and a circuit diagram.
The work is facilitated by the presence of corresponding markings on almost all the details and the board itself, which really turns the process into assembling a children's construction set by an adult. On the diagrams and instructions, all the necessary data is clearly visible and you can figure it out without even knowing a foreign language.
The output should be a device with the following characteristics:
- Input voltage: DC 9V;
- Maximum input voltage: 50 Vpp (1:1 probe)
- Current consumption 120 mA;
- Signal bandwidth: 0-200KHz;
- Sensitivity: electronic bias with vertical adjustment option 10mV/div - 5V/Div (1 - 2 - 5);
- Discrete frequency: 1 Msps;
- Input resistance: 1 MΩ;
- Time Interval: 10us / Div - 50s / Div (1 - 2 - 5);
- Measurement accuracy: 12 bits.
Step-by-step instructions for assembling the DSO138 constructor
Should be considered in more detail detailed instructions for the manufacture of an oscilloscope of this brand, because other models are assembled in a similar way.
It should be noted that in this model the board comes with a soldered 32-bit Cortex™ microcontroller on the M3 core. It works with two 12-bit inputs with a characteristic of 1 μs and operates in a maximum frequency range of up to 72 MHz. Having this device already mounted makes the task somewhat easier.
Step 1. It is most convenient to start the installation with smd components. It is necessary to take into account the rules when working with a soldering iron and a board: do not overheat, hold no longer than 2 s, do not close different parts and tracks together, use solder paste and solder.
Step 2. Solder the capacitors, inductors and resistances: you need to insert the specified part into the place allotted for it on the board, cut off the excess leg length and solder it on the board. The main thing is not to confuse the polarity of the capacitors and not to close adjacent tracks with a soldering iron or solder.
Step 3. We mount the remaining parts: switches and connectors, buttons, LED, quartz. Particular attention should be paid to the side of the diodes and transistors. Quartz has a metal in its structure, so you need to ensure that its surface does not directly contact the tracks of the board or take care of the dielectric lining.
Step 4. 3 connectors are soldered to the display board. After completing the manipulations with the soldering iron, you need to rinse the board with alcohol without auxiliary means - no cotton wool, disks or napkins.
Step 5. Dry the board and check how well the soldering was carried out. Before connecting the shield, you need to solder two jumpers to the board. The existing bitten-off conclusions of the parts will be useful in this.
Step 6. To check the operation, you need to turn on the device in a network with a current of 200 mA and a voltage of 9 V.
The check consists in taking indicators from:
- Connector 9 V;
- Reference point 3.3 V.
If all parameters correspond to the required values, you need to disconnect the device from the power supply and install the JP4 jumper.
Step 7. Insert the display into the 3 available connectors. You need to connect the probe for the oscilloscope to the input, turn on the power with your own hands.
The result of proper installation and assembly will be the appearance on the display of its number, type of firmware, its version and the developer's website. After a few seconds it will be possible to observe the sine waves and the scale with the probe turned off.
Computer prefix
When assembling this simple device, you will need a minimum number of parts, knowledge and skills. The circuit diagram is very simple, except that you will need to make the board yourself to assemble the device.
The dimensions of the do-it-yourself oscilloscope attachment will be about the same as a matchbox or a little larger, so it is best to use a plastic container or a battery box of this size.
Having placed the assembled device with ready-made outputs in it, you can begin to organize work with a computer monitor. To do this, download the Oscilloscope and Soundcard Oscilloscope programs. You can test their work and choose the one you like best.
The connected microphone will also be able to relay sound waves to the connected oscillator, the program will reflect the changes. Such a set-top box is connected to a microphone or line input and does not require any additional drivers.