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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 can be obtained for 6, 11 and 14 steps with autotransformer switching at the input, as well as for 6, 11 and 14 steps with output switching. Depending on the autotransformers used, the circuit for its inclusion 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 the attacker to a high-voltage electric current discharge. The circuit allows you to get a voltage 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, the electroshock device can be used as a personal 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 is easy to do at home.
A stun gun is a device for individual self-defense against ill-wishers by means of electric shock of high intensity.
This block can work under the control of any previously developed controller with minor modifications.
Its advantage is almost 4 times higher efficiency in comparison with the "input" switching unit and 2 times higher efficiency in comparison with the "output" switching unit!!!
The device is intended 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, activated in case of an alarm. It can also be useful in agriculture and household plots to create an electric fence for the garden from animals (for this, it is enough to install stakes with two bare wires stretched around the perimeter).
This circuit is the latest development in a series of mains voltage stabilizer circuits. It takes into account all the shortcomings in the operation of the previous schemes, as well as wishes to increase the reliability of the stabilizer. To do this, a control unit on the DD2 chip was introduced into the circuit for the state of the outputs of the microcontroller DD1, and a control sensor on the diode bridge VD10 and transistors VT7-VT10, which, in addition to the synchronization function, monitors the state of the triacs, which allows, in the event of failure of one of the power switches avoid interwinding short circuits of the autotransformer and, as a result, protect consumers from failure.
This device will be useful for cleaning indoor air or killing bacteria in infectious diseases. A low concentration of ozone also makes it possible to improve the long-term storage of products, for example in the cellar. The operation of the device is based on the property of air, when electric sparks are passed through it, to form a new substance - OZONE. 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 located in the upper layers of the atmosphere and is formed as a result of atmospheric discharges).
Original circuit ranges: ESR=0-100Ω, C=0pF-5000µF.
I want to pay special attention to the fact that the device is still in the process of finalizing 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. The resistance of resistors R2, R3 was reduced to 1.13K, and I picked up a pair with an accuracy of one ohm (0.1%). Thus, I increased the test current from 1mA to 2mA, while the non-linearity of the current source decreased (due to the removal of R4, R5), the voltage drop across the capacitor increased, which contributes to an increase in the accuracy of ESR measurement.
And of course Kusil corrected. U5b.
1. Introduced power filters at the input and output of the converter + 5V / -5V (in the photo the scarf is standing vertically and there is a converter with filters)
2. put the ICSP connector
3. introduced the R / C mode switch button (in the "original" the modes were switched by an analog signal coming to 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 a signal of inclusion every 2 minutes.
6. Powered the inverters by their parallel pairwise connection (with a test current of 1-2mA it is not necessary, I just dreamed of increasing the measurement current to 10mA, which has not yet been possible)
7. I put a 51 ohm resistor in series with P2 (to avoid short circuit).
8.Vyv. I shunted the contrast adjustment with a 100nf capacitor (I soldered it to the indicator). Without it, when the P7 engine was touched with a screwdriver, the indicator began to consume 300mA! I almost burned the LM2930 along with the indicator!
9. I put a blocking capacitor on the power supply of each MS.
10. adjusted the circuit board.
Software
1. removed the DC mode (most likely I will return it back)
2. Introduced a tabular correction of non-linearity (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 the calibration subroutine
5. wrote support for buttons and buzzer
6. introduced an indication of the battery charge - numbers from 0 to 5 in the last digit of the display.
I did not interfere with the capacitance measurement unit either 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 you breathe on it, the readings begin to "swim". The reason for this is the high resistance of R19, R18, R25, R22. By the way, can someone explain to me why the hell is the cascade on the U5a such a large input impedance ???
In short, the analog part was filled with varnish - after which the sensitivity completely disappeared.
The magazine ELEKTOR, as far as I know, 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 a flame
An external probe (RF head) is used to measure high-frequency voltages.
The appearance of the avometer and the RF head is shown in fig. 22.
The device is mounted in an aluminum case or in a plastic box measuring approximately 200X115X50 mm. The front panel is made of sheet textolite or getinaks 2 mm thick. The body and front panel can also be made from 3 mm plywood impregnated with Bakelite varnish.
Rice. 21. Diagram of an avometer.
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 housing, rotated 180 ° and put in its original place. This change is made so that the switch contacts close when the resistor is fully withdrawn. If this is not done, then the universal shunt will always be connected to the device, reducing its sensitivity.
All fixed resistors, except for R4-R7, must be with a resistance tolerance of no more than ± 5%. Resistors R4-R7 shunting the device when measuring currents are 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 Plexiglas 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 the same as in the diagram. Otherwise, the arrow of the device will deviate in the opposite direction. The same applies to the avometer diodes.
The universal shunt is made of wire with high resistivity and is 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 BC-1 type resistor 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 1468 ohm.
Fig 22. Appearance of the avometer.
Graduation. The avometer scale is shown in fig. 23. Graduation of the voltmeter scale is carried out according to the reference control voltmeter constant voltage according to the scheme shown in Fig. 24, a. A source of constant voltage (at least 20 V) can be a low-voltage rectifier or a battery composed of four KBS-L-0.50. By turning the variable resistor slider, marks 5, 10 and 15 b are applied to the scale of a home-made device, and four divisions between them. On the same scale, voltages up to 150 V are measured, multiplying the readings of the device by 10, and voltages up to 600 V, multiplying the readings of the device by 40.
The current measurement scale up to 15 mA must exactly correspond to the scale of the constant voltage voltmeter, which is checked using a reference milliammeter (Fig. 24.6). If the readings of the avometer differ from the readings of the control device, then by changing the length of the wire on the resistors R5-R7, the resistance of the universal shunt is adjusted.
In the same way, the scale of the voltmeter of alternating voltages is calibrated.
To calibrate the ohmmeter scale, you must use a resistance box or use fixed resistors with a tolerance of ± 5% as reference ones. Before starting the calibration, with the resistor R11 of the avometer, the arrow of the device is set to the extreme right position - against the number 15 of the scale of direct currents and voltages. This will be the "0" of the ohmmeter.
The range of resistance measured by the avometer is large - from 10 ohms to 2 MΩ, the scale turns out to be dense, therefore only the resistance figures of 1 kΩ, 5 kΩ, 100 kΩ, 500 kΩ and 2 MΩ are applied to the scale.
With an autometer, you can measure the static current gain of transistors Vst up to 200. The scale of these measurements is uniform, therefore Divide it into equal intervals in advance and check for transistors with known Vst values. If the readings of the device differ slightly from the actual values, then change the resistance of the resistor R14 to real values these transistor parameters.
Rice. 23. Avometer scale.
Rice. 24. Schemes of graduation of the scales of the voltmeter and milliammeter of the avometer.
To check the remote probe when measuring high-frequency voltage, VKS-7B voltmeters and any high-frequency generator are needed, in parallel to which the probe is connected. The wires from the probe are included in the "Common" and "+15 V" sockets of the avometer. A high frequency is applied to the input of a tube voltmeter through a variable resistor, as when calibrating a constant voltage scale. The readings of the lamp voltmeter should correspond to the DC voltage scale at 15 V of the avometer.
If the readings when checking the device on a tube voltmeter do not match, then the resistance of the resistor R13 of the probe is somewhat changed.
Using a probe, high-frequency voltages are measured only up to 50 V. Higher voltages may cause the diode to break down. When measuring voltage frequencies above 100-140 MHz, the device introduces significant measurement errors due to the shunting action 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, circle them with ink.
