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Homemade electronic devices. Homemade devices - design, description
This article will discuss the designs of stabilizers based on the ATmega8535-16PI microcontroller. Using different firmware, options for 6, 11 and 14 stages with input autotransformer switching, as well as 6, 11 and 14 stages with output switching can be obtained. Depending on the autotransformers used, its connection circuit and power switches, different stabilizer powers can be obtained in the range from 1.2 to 11 kW.
The device is designed for active self-defense by exposing an attacker to a high-voltage electric current. The circuit makes it possible to obtain voltages of up to 80,000 V at the output contacts, which leads to air breakdown and the formation of an electric arc (spark discharge) between the contact electrodes. Since a limited current flows when touching the electrodes, there is no threat to human life. Due to its small size, an electric shock device can be used as an individual security device or work as part of a security system for the active protection of a metal object (safe, metal door, door lock, etc.). In addition, the design is so simple that it does not require the use of industrial equipment- everything can be easily done at home.
A stun gun is a device for individual self-defense from ill-wishers through high-voltage electric shock.
This unit can be controlled by any previously developed controller with minor modifications.
Its advantage is almost 4 times higher efficiency compared to the “input” switching unit and 2 times higher efficiency compared to the “output” switching unit!!!
The device is designed for active protection of a metal door of an apartment or a safe and can be... used in conjunction with other security devices as an additional one, activated in case of an alarm. It can also be useful in agriculture and homesteading for creating an electric fence for the garden against animals (to do this, it is enough to install stakes around the perimeter with two exposed wires stretched).
This circuit is the latest development in a series of network voltage stabilizer circuits. It takes into account all the shortcomings in the operation of previous schemes, as well as wishes to increase the reliability of the stabilizer. To do this, a control unit on the DD2 microcircuit for the state of the outputs of the DD1 microcontroller was introduced into the circuit, and a control sensor on the VD10 diode bridge and VT7-VT10 transistors, which, in addition to the synchronization function, monitors the state of the triacs, which allows if one of the power switches fails avoid inter-winding short circuits of the autotransformer and, as a result, protect consumers from failure.
This device will be useful for purifying indoor air or destroying bacteria in infectious diseases. A small concentration of ozone can also improve long-term storage of products, for example in the basement. The operation of the device is based on the ability of air to form a new substance - OZONE - when electric sparks are passed through it. Under normal conditions, it is a gas that has a characteristic odor (the ozone molecule consists of three oxygen atoms and under natural conditions is found in the upper layers of the atmosphere and is formed as a result of atmospheric discharges).
Ranges of the original circuit: ESR=0-100Ohm, C=0pF-5000µF.
I would like to draw special attention to the fact that the device is still in the process of being finalized, both software and hardware, but continues to be actively used.
My improvements regarding http://www.vecoven.com/elec/capa/capa.html:
Hardware
0. Removed R4, R5. Reduced the resistance of resistors R2, R3 to 1.13K, and selected a pair with an accuracy of one ohm (0.1%). Thus, I increased the test current from 1mA to 2mA, while the nonlinearity of the current source decreased (due to the removal of R4, R5), the voltage drop across the capacitor increased, which helps to increase the accuracy of ESR measurement.
And of course Kusil corrected it. U5b.
1. Introduced power filters at the input and output of the +5V/-5V converter (in the photo of the scarf standing vertically there is a converter with filters)
2. installed the ICSP connector
3. introduced a button for switching R/C modes (in the “original” the modes were switched by an analog signal arriving at RA2, the origin of which is described in the article extremely vaguely...)
4. Introduced a forced calibration button
5. Introduced a buzzer confirming the pressing of the buttons and giving an on signal every 2 minutes.
6. I increased the power of the inverters by connecting them in parallel in pairs (with a test current of 1-2 mA, this is not necessary, I just dreamed of increasing the measurement current to 10 mA, which has not yet been possible)
7. I placed a 51 ohm resistor in series with P2 (to avoid short circuit).
8.Vyv. I bypassed the contrast adjustment with a 100nf capacitor (soldered onto the indicator). Without it, when the screwdriver touched the P7 engine, the indicator began to consume 300mA! I almost burned the LM2930 along with the indicator!
9. I installed a blocking capacitor to power each MS.
10. Adjusted the printed circuit board.
Software
1. removed the DC mode (most likely I will return it back)
2. Introduced a tabular nonlinearity correction (at R>10 Ohm).
3. limited the ESR range to 50 Ohms (with the original firmware the device went off scale at 75.6 Ohms)
4. added a calibration subroutine
5. wrote support for buttons and buzzer
6. entered the battery charge indication - numbers from 0 to 5 in the last digit of the display.
The capacitance measurement unit was not interfered with either by software or hardware, with the exception of adding a resistor in series with P2.
I have not yet drawn a schematic diagram reflecting all the improvements.
The device was very sensitive to humidity! As soon as you breathe on it, the readings begin to “float”. It’s all due to the large resistance R19, R18, R25, R22. By the way, can someone explain to me why the f*ck the cascade on U5a has such a high input impedance???
In short, I filled the analog part with varnish - after which the sensitivity completely disappeared.
As far as I know, the ELEKTOR magazine is German, the authors of the articles are Germans and they publish it in Germany, at least the German version.
m.ix, let's joke in the flame
To measure high-frequency voltages, a remote probe (RF head) is used.
The appearance of the avometer and HF head is shown in Fig. 22.
The device is mounted in an aluminum housing or in a plastic box with dimensions of approximately 200X115X50 mm. The front panel is made of sheet PCB or getinax 2 mm thick. The body and front panel can also be made of 3 mm thick plywood impregnated with bakelite varnish.
Rice. 21. Avometer diagram.
Details. Microammeter type M-84 for a current of 100 μA with an internal resistance of 1,500 ohms. Variable resistor type TK with switch Vk1. The switch must be removed from the resistor body, rotated 180° and placed in its original place. This change is made so that the switch contacts close when the resistor is fully removed. If this is not done, the universal shunt will always be connected to the device, reducing its sensitivity.
All fixed resistors, except R4-R7, must have a resistance tolerance of no more than ±5%. Resistors R4-R7 shunt the device when measuring currents - wire.
A remote probe for measuring high-frequency voltages is placed in an aluminum case from an electrolytic capacitor. Its parts are mounted on a plexiglass plate. Two contacts from the plug are attached to it, which are the input of the probe. The input circuit conductors should be located as far as possible from the probe output circuit conductors.
The polarity of the probe diode should only be as shown in the diagram. Otherwise, the instrument needle will deviate in the opposite direction. The same applies to avometer diodes.
A universal shunt is made of wire with high resistivity and mounted directly on the sockets. For R5-R7, a constantan wire with a diameter of 0.3 mm is suitable, and for R4, you can use a resistor of the BC-1 type with a resistance of 1400 ohms, winding a constantan wire with a diameter of 0.01 mm around its body, so that their total resistance is 1,468 ohms.
Figure 22. Appearance of the avometer.
Graduation. The avometer scale is shown in Fig. 23. The voltmeter scale is calibrated using a reference reference voltmeter DC voltage according to the diagram shown in Fig. 24, a. The source of constant voltage (at least 20 V) can be a low-voltage rectifier or a battery made up of four KBS-L-0.50. By turning the slider of the variable resistor, marks of 5, 10 and 15 b are applied to the scale of the homemade device, with four divisions between them. Using the same scale, voltages up to 150 V are measured, multiplying the device readings by 10, and voltages up to 600 V, multiplying the device readings by 40.
The scale of current measurements up to 15 mA must exactly correspond to the scale of a constant voltage voltmeter, which is checked using a standard milliammeter (Fig. 24.6). If the avometer readings differ from the readings of the control device, then by changing the length of the wire on resistors R5-R7, the resistance of the universal shunt is adjusted.
The scale of an alternating voltage voltmeter is calibrated in the same way.
To calibrate the ohmmeter scale, you must use a resistance magazine or use constant resistors with a tolerance of ±5% as reference ones. Before starting calibration, use resistor R11 of the avometer to set the instrument needle to the extreme right position - opposite number 15 of the scale of direct currents and voltages. This will be "0" on the ohmmeter.
The range of resistances measured by an avometer is large - from 10 ohms to 2 megohms, the scale is dense, so only resistance numbers of 1 kohm, 5 kohms, 100 kohms, 500 kohms and 2 megohms are put on the scale.
With an Avometer you can measure the static gain of transistors with respect to current Vst up to 200. The scale of these measurements is uniform, so they divide it into equal intervals in advance and check it against transistors with known Vst values. If the readings of the device differ slightly from the actual values, then change the resistance of resistor R14 to real values these transistor parameters.
Rice. 23. Avometer scale.
Rice. 24. Schemes for calibrating the scales of a voltmeter and milliammeter of an avometer.
To check the remote probe when measuring high-frequency voltage, you need VKS-7B voltmeters and any high-frequency generator, in parallel with which the probe is connected. The wires from the probe are plugged into the “Common” and “+15 V” sockets of the avometer. A high frequency is supplied to the input of a lamp voltmeter through a variable resistor, as when calibrating a constant voltage scale. The lamp voltmeter readings should correspond to the 15 V DC voltage scale of the avometer.
If the readings when checking the device using a lamp voltmeter do not match, then slightly change the resistance of resistor R13 of the probe.
The probe measures high-frequency voltages only up to 50 V. At higher voltages, diode breakdown may occur. When measuring voltages at frequencies above 100-140 MHz, the device introduces significant measurement errors due to the shunting effect of the diode.
All calibration marks on the ohmmeter scale are made with a soft pencil and only after checking the accuracy of the measurements are they outlined with ink.
