Microelectric Voltage Generated Machine
The tachometer generator converts the shaft rotation indicator into an electrical signal. Its operation uses the properties of the angular velocity of the rotor, the excitation flow, which is proportional to the generated EMF. Most modern tachogenerators are the permanent magnet type. These devices use a rotating joint, one end of which is connected to the machine shaft, inducing an electromotive force (voltage) proportional to the speed of the shaft. The armature contacts are connected to the voltmeter circuit, converting the voltage into a speed value.
Exploitation
The simplest tachometer, made with your own hands on the basis of a calculator, works after soldering the contacts to the addition button of the computer.
Measuring the rotation speed is performed as follows:
- The micro calculator turns on.
- The “+” and “1” keys are activated synchronously.
- The gadget starts up and measurements are taken on it. To ensure accurate readings, the stopwatch should be turned on at the same time as the calculator.
- Wait 30 seconds and then look at the screen. The corresponding value should appear on it.
- This indicator is the number of revolutions in 30 seconds. Multiplying the number by two, we get the number of rotations per minute.
Appearance of the calculator
As you can see in the photo of the calculator, in the upper part there is an area for entering data. After completing all the logical operations, the balls show the result of the operation below.
Data entry is carried out with balls. There is a ball - 1, there is no ball - 0. The bit on the right is the smallest bit of the number. Before starting work, some parts of the calculator should be returned to their original position. After specifying the initial values, a strip of cardboard is moved aside, which holds the balls in their original position - and the addition process begins.
For example, this is what the initial position of the balls looks like for the operation 7+5 (0111 + 0101).
Master class on making a digital and analog homemade tachometer
A tachometer is a device designed to measure engine speed while driving and display this information to the driver. The received data is shown to the motorist on the dashboard or, if the device was installed additionally, on the corresponding screen in the cabin. This material will allow you to learn how to build a tachometer at home with your own hands.
How to make a calculator or form for a website: a review of 4 special constructors
Reading time: 25 minutes Don't have time to read? No time?
Just a couple of years ago, creating a calculator required a budget for contacting a freelancer or studio, or basic knowledge of mathematical expressions and technologies in order to configure a module for your CMS or write it from scratch. Now you just need to move the mouse to get the desired result, and the price of the issue has dropped to 0 rubles. Let's figure out how to make a calculator for the site.
How much does it cost to make a calculator? The studio may ask you for 25 thousand rubles:
Demand gave birth to supply: services began to appear all over the world offering to simplify and reduce the cost of creating a calculator or form for a website. After reviewing a dozen services in Russian and English, we chose four that you can use to create calculators and forms for your websites.
Electronic tachometer circuit on Arduino
To assemble the device, you will naturally need an Arduino microcontroller. If it is not there, then any other controller with similar characteristics will do, but then you will need to additionally assemble the programmer. Also for this circuit you need resistors 33 kOhm, 270 Ohm, 10 kOhm in the form of a potentiometer. You can also purchase a blue LED, an infrared LED and a photodiode. Next, find the DSV display and the shift register chip labeled 74NS595. It uses an optical sensor and the principle of reflecting rays. With this system, you don't have to worry about how thick the rotor should be, and the number of rotor blades won't change the performance. The sensor will be able to accurately read the revolutions.
The base (bed) of the winding machine
You can make a machine for winding transformers from any durable, easily processed material. The most suitable would be: metal, plywood (wood) or plastic. Depending on what you have available and what you like to work with most, you can give preference to one material or another.
I mostly make homemade things from what I have on hand, and in this case, in the rubble of junk called “useful around the house” I found scraps of 10 mm semi-rigid plastic, which I successfully used in the design of the winder and its elements.
Initially, during development, it is necessary to make a test layout, think through the layout of the winder, and ask yourself what necessary functions the device should perform. During the prototyping process, it is easy to add and improve, adjust the dimensions, which will allow you to get the most successful option at the end.
According to the project, we have three axes:
The first axis (winder) - the winding coil of the transformer will rotate on it. At one end there will be a counter for the number of turns made, and at the other end there will be an axle rotation drive with a set of pulleys. The drive can be manual in the form of a handle attached to an axis or electric in the form of a stepper motor.
The second axis (stacker) - the lead of the wire stacker will “run” on it, and the second set of pulleys will be attached to the axis, which will be interfaced with the first set of pulleys on the first axis through a belt drive using a belt.
The third axis (reel holder) serves as a support for the reel with winding wire.
At the design stage, it is necessary to correctly space the axes between each other so that the frame of the winding transformer coil does not cling to the machine and does not touch another axis, and also select the height of the wire coil so that you can freely hang coils of different sizes. An additional axis can be provided for winding and winding wire from reel to reel.
According to the markings on the selected material for the bed, using a hacksaw for metal, we cut out parts of the base of the machine (sides, bottom, cross members), and also drill the necessary holes. Using metal corners and self-tapping screws, we fasten all the components together.
Homemade car electronic tachometer
An electronic tachometer is a digital device made of electronic components and used to measure the speed of an electric motor or any other rotating object in revolutions per minute. It is located in the car dashboard and has good visibility and measurement accuracy.
Simple speed metronome
Tachometer comes from two Greek words: “tacho” meaning “speed” and “metronome” meaning “to measure”. It works on the principle of a generator and determines the voltage corresponding to the speed of the shaft. It is also known as a revolution counter. Principle of operation:
- induction;
- electromagnetic;
- electronic;
- optic.
Historically, the first mechanical tachometer was developed based on the measurement of centrifugal force. In 1817 they were used to measure the speed of traction machines, but after 1840 they were used primarily to measure the speed of vehicles. A digital tachometer is an optical sensor designed to determine the angular velocity of a rotating element. Areas of use:
Device and principle of operation.
Feeding unit.
The feeding unit is designed to attach a reel of wire of various sizes to it, and provide tension on the wire. It includes a bobbin fastening mechanism and a shaft braking mechanism.
Figure 2.
Feeder unit.
Braking.
Without braking the feed reel, the winding of the wire on the frames will be loose and high-quality winding will not work. Felt tape “2” slows down drum “1”. Turning the lever “3” tightens the spring “4” - adjusting the braking force. For different wire thicknesses, its own braking is adjusted. Off-the-shelf VCR parts are used here.
Figure 3.
Braking mechanism.
Bobbin centering.
The small dimensions of the machine and the location in close proximity of the winding reel and the feed reel with wire required the introduction of an additional mechanism for centering the feed reel.
Figure 4, 5.
Centering mechanism.
When winding the coil, the wire from the reel acts on the shutter “5”, made in the form of a “fork” and the stepper motor “3”, through a gearbox with division 6 and a toothed belt, along roller guides “4”, automatically moves the reel in the desired direction. Thus, the wire is always in the center, see Fig. 4, Fig. 5:
Figure 6.
Sensors, rear view.
Composition and design of sensors.
19. Optical sensors for the bobbin centering mechanism. 5. A curtain covering the sensors of the reel centering mechanism. 20. Curtains covering the positioner direction switching sensors. 21. Optical sensors for switching the direction of the positioner.
Positioner.
Curtains “20” fig. 6 — the winding limit is set. The stepper motor moves the stacker mechanism until the curtain blocks one of the sensors “21” fig. 6, after which the laying direction changes. You can change the laying direction at any time using buttons “1” fig. 7.
Figure 7.
Stacker.
Rotation speed of stepper motor “9” fig. 7, synchronized using sensor “10”, “11” Fig. 8, with the rotation of the wound coil and depends on the diameter of the wire set in the menu. The diameter of the wire can be set to 0.02 - 0.4mm. Using knob “8” fig. 7, you can move the entire positioner to the side without changing the winding boundaries. In this way, it is possible to wind another section in multi-section frames.
Figure 8.
Optosensor.
Composition of the positioner and opto-sensor (Fig. 7-8).
1. Buttons for manually switching the laying direction. 2. LEDs for laying direction. 3. Curtains covering the positioner direction switching sensors. 4. Linear bearing. 5. Caprolon nut. 6. Lead screw. Diameter 8mm, thread pitch 1.25mm. 7. Ball furniture guides. 8. Handle for moving the positioner to another section when winding sectional windings. 9. Stepper motor. 10. Optical timing sensor. 11. Disk covering the synchronization sensor. 18 slots.
Receiving node.
Figure 9.
Receiving node.
Figure 10, 11.
Receiving unit.
1. Turn counter. 2. Commutator high-speed motor. 3. Reducer gear. 4. “Counter reset” button. 5. Speed adjustment. 6. “Start winding” switch. 7. Fastening of the winding reel.
The rotation of the wound coil is produced by a high-speed commutator motor through a gearbox. The gearbox consists of three gears with a total pitch of 18. This provides the necessary torque at low speeds. The motor speed is adjusted by changing the supply voltage.
Figure 12, 13.
Fastening a frame with a hole.
The design of the receiving unit allows you to fasten both frames with a central hole and frames without such holes, which is clearly visible in the figures.
Figure 14, 15.
Fastening a frame without a hole.
How the counter works
The remote mini frequency meter/tachometer/pulse counter is very simple and takes into account what the phototransistor sees after being reflected from an object illuminated by an infrared emitting LED (the IR diode is only activated at the moment of counting). You can make the circuit almost entirely on a microcontroller without using an op-amp, but it was decided to use an op-amp to increase the sensitivity of the device. The base is a modified and simplified version of the heart rate monitoring unit.
In mode “1”, it is enough to bring the front part of the counter to the tested area and wait for the signal to stabilize. The measurement lasts 0.5 s, and if it is identical in at least two consecutive measurements, then the program displays the result by cycling the digits on the display separating each digit with a short blanking.
Due to the simplification of the operation and reduction of measurement time, the result always becomes even - the program multiplies it by 2, which will allow the result to be calculated “per second”. Despite this rounding, the results are surprisingly accurate and the possible measurement error is relatively small. In practice, the frequency was measured in the range of up to 40 kHz, and it copes with this without problems.
As soon as we read the result and want to measure something, briefly press the button and measure again. But when we hold the button, we exit the current mode and switch to another.
In pulse counting mode “2”, measurement begins immediately after confirming the mode (short press of the button). A second press stops the measurement and displays the result. Reset is a second press that starts the next counting cycle. At this point, you can hold the button longer and return to mode selection mode.
Components of a winding machine and its operating principle
The elements of the winding machine were assembled slowly. Almost everything was taken from old Soviet film equipment. Moving parts: handle, axle studs, guide roller - everything is equipped with bearings. Studs, nuts, washers and angles were purchased at a hardware store. I only had to spend money on studs, long nuts and angles. Otherwise, everything is made from available materials.
To accurately select the wire winding density, a set of several pulleys is threaded onto the stacker pin. So, in the case of loose winding, it was possible to move the belt one size and adjust the speed of rotation of the axes. During the process of winding the wire, the belt is twisted depending on the direction of the winding stroke according to the figure-of-eight shape or the direct position of the belt. You should make a couple of dozen test turns to correctly adjust the pulleys to the diameter of the wire.
A base is made from wood or other material in the shape of the inside of the transformer coil and is fixed to the stud with wing nuts. You can also make universal holding corners to secure the coil. A demonstration of the operation of the winding machine is shown in the video:
[Here will be a video of the transformer winding process]
About the author:
Greetings, dear readers! My name is Max. I am convinced that almost everything can be done at home with your own hands, I am sure that everyone can do it! In my free time I like to tinker and create something new for myself and my loved ones. You will learn about this and much more in my articles!
Many household appliances and industrial automation devices of relatively recent production years have mechanical counters installed. They are products on a conveyor belt, turns of wire in winding machines, etc. In the event of a failure, finding a similar meter is not easy, and it is impossible to repair due to the lack of spare parts. The author proposes to replace the mechanical counter with an electronic one. An electronic counter, developed to replace a mechanical one, turns out to be too complex if it is built on microcircuits with a low and medium degree of integration (for example, the K176, K561 series). especially if a reverse account is needed. And in order to maintain the result when the power is turned off, it is necessary to provide a backup battery.
But you can build a counter on just one chip - a universal programmable microcontroller that includes a variety of peripheral devices and is capable of solving a very wide range of problems. Many microcontrollers have a special memory area - EEPROM. Data written into it (including during program execution), for example, the current counting result, is saved even after the power is turned off.
The proposed counter uses the Attiny2313 microcontroller from the AVR family from Almel. The device implements reverse counting, displaying the result with cancellation of insignificant
hive on a four-digit LED indicator, storing the result in EEPROM when the power is turned off. An analog comparator built into the microcontroller is used to timely detect a decrease in supply voltage. The counter remembers the counting result when the power is turned off, restoring it when turned on, and, similarly to a mechanical counter, is equipped with a reset button.
The counter circuit is shown in the figure. Six lines of port B (РВ2-РВ7) and five lines of port D (PDO, PD1, PD4-PD6) are used to organize dynamic indication of the counting result on the LED indicator HL1. The collector loads of phototransistors VT1 and VT2 are resistors built into the microcontroller and enabled by software that connect the corresponding pins of the microcontroller to its power supply circuit.
An increase in the counting result N by one occurs at the moment the optical connection between the emitting diode VD1 and the phototransistor VT1 is interrupted, which creates an increasing level difference at the INT0 input of the microcontroller. In this case, the level at the INT1 input must be low, i.e., the phototransistor VT2 must be illuminated by the emitting diode VD2. At the moment of a rising differential at the INT1 input and a low level at the INT0 input, the result will decrease by one. Other combinations of levels and their differences at the inputs INT0 and INT1 do not change the counting result.
Once the maximum value of 9999 is reached, counting continues from zero. Subtracting one from the zero value gives the result 9999. If counting down is not needed, you can exclude the emitting diode VD2 and phototransistor VT2 from the counter and connect the INT1 input of the microcontroller to the common wire. The count will only continue to increase.
As already mentioned, the detector of a decrease in supply voltage is the analog comparator built into the microcontroller. It compares the unstabilized voltage at the output of the rectifier (diode bridge VD3) with the stabilized voltage at the output of the integrated stabilizer DA1. The program cyclically checks the state of the comparator. After disconnecting the meter from the network, the voltage on the rectifier filter capacitor C1 drops, and the stabilized voltage remains unchanged for some time. Resistors R2-R4 are selected as follows. that the state of the comparator in this situation is reversed. Having detected this, the program manages to write the current counting result to the EEPROM of the microcontroller even before it stops functioning due to the power being turned off. The next time you turn it on, the program will read the number written in EERROM and display it on the indicator. Counting will continue from this value.
Due to the limited number of microcontroller pins, to connect the SB1 button, which resets the counter, pin 13 was used, which serves as the inverting analog input of the comparator (AIM) and at the same time as the “digital” input of PB1. The voltage divider (resistors R4, R5) here sets the level perceived by the microcontroller as high logical. When you press the SB1 button, it will become low. This will not affect the state of the comparator, since the voltage at the AIN0 input is still greater than that at AIN1.
When the SB1 button is pressed, the program displays a minus sign in all digits of the indicator, and after releasing it, it starts counting from zero. If you turn off the power to the meter while the button is pressed, the current result will not be written to the EEPROM, and the value stored there will remain the same.
The program is designed in such a way that it can be easily adapted to a meter with other indicators (for example, with common cathodes), with a different printed circuit board layout, etc. A slight correction of the program will also be required when using a quartz resonator for a frequency that differs by more than 1 MHz from the specified one.
When the source voltage is 15 V, measure the voltage at pins 12 and 13 of the microcontroller panel relative to the common wire (pin 10). The first should be in the range of 4...4.5 V, and the second should be more than 3.5 V, but less than the first. Next, the source voltage is gradually reduced. When it drops to 9 ... 10 V, the difference in voltage values at pins 12 and 13 should become zero and then change sign.
Now you can install the programmed microcontroller into the panel, connect the transformer and apply mains voltage to it. After 1.5...2 s you need to press the SB1 button. The counter indicator will display the number 0. If nothing is displayed on the indicator, check the voltage values at the AIN0.AIN1 inputs of the microcontroller again. The first must be greater than the second.
When the counter has been successfully launched, all that remains is to check the correctness of the count by alternately shading the phototransistors with a plate opaque to IR rays. For greater contrast, it is advisable to cover the indicators with a red organic glass filter.
Also, if anyone assembles a counter on Atiny2313 without quartz, I programmed the Fuses like this
source ASM Firmware
In amateur radio practice, there is often a need to wind/rewind various windings of transformers, chokes, relays, etc. When developing this machine, the following tasks were set:
1. Small dimensions. 2. Smooth spindle start. 3. Counter up to 10,000 turns (9999). 4. Winding with automatic wire laying. Laying pitch (wire diameter) 0.02 - 0.4mm. 5. Possibility of winding sectional windings without reconfiguration. 6. Possibility of fastening and winding frames without a central hole.
Figure 1.
External view of the winding machine.
Composition of the winding machine.
1. Feed reel (reel of wire). 2. Braking (brake mechanism). 3. Stepper motor for bobbin centering. 4. Ball furniture guides. 5. Shutter of optical sensors of the reel centering mechanism. 6. Handle for moving the positioner to another section when winding sectional windings. 7. Buttons for manually switching the laying direction. 8. LEDs for laying direction. 9. Positioner stepper motor. 10. Shutters of optical winding boundary sensors. 11. Positioner screw. 12. Ball furniture guides. 13. Winding reel. 14. Winding motor. 15. Turn counter. 16. Setting buttons. 17. Optical synchronization sensor. 18. Speed controller.
