Installation 

Homemade portable phone charger. DIY wireless phone charger. How it works? Video illustration

Greetings, dear readers. In today's article, let's talk about the current technology today - wireless charging for phones. Surely you have heard how branded companies focus on it, presenting another portable device with its support. Not wanting to spend their money, many people stay with their old mobile phone, never ceasing to dream of trying out wireless charging.

Do-it-yourself wireless charging is a very simple and fairly quick solution. Read the instructions and watch the video. Interesting, right? Then let's go in order. But be sure to read the advice at the end of the article!

Something new? No, the well-known "old"

When I first saw wireless charging, I thought that the manufacturers had made a breakthrough by opening some new technology. Fortunately, there is the Internet, which told me the truth. In fact, the advent of wireless power transmission was made possible by the discovery of the law by André Marie Ampère, who proved that electricity produces a magnetic field.

And it happened, for a moment, almost 200 years ago. In subsequent years, a number of scientists confirmed the existence electromagnetic waves, and Nikola Tesla devoted years of his life to studying the possibility of transmitting energy at a distance. By means of electromagnetic induction, the physicist managed to light an incandescent lamp at a distance.

Standard qi

Of course, wireless power transmission was of interest to many areas of human life, but long time did not go beyond the walls of the laboratories. Already in this century, companies that develop consumer electronics (tablets, smartphones) have begun to take initiatives to create wireless chargers. A huge contribution was made by the Wireless Power Consortium, which developed the Qi (“Qi”) standard for low currents.

The specification of the standard was free and available, so very soon it began to be used in portable technology. Three years later, Qi acquired a specification for medium currents. There are other standards, but they are more complicated than Qi, and less common. More recently, in 2015, scientists at the University of Washington found out that energy can be transmitted through Wi-Fi networks. We are waiting for the smartphone to charge by connecting to the router.

How Qi wireless charging works

Well, already from the name of the device it becomes clear that the gadget does not require wires to transfer energy. The principle of operation is very simple. The charger gets a built-in coil (copper), which takes on the role of the creator and transmitter of electricity. magnetic field already on the receiver coil placed in the smartphone (may be above the battery or back cover). Electromagnetic radiation occurs when a mobile phone with a receiver is in close proximity to the transmitter (usually about 4 centimeters). Then capacitors and a rectifier (a low-power semiconductor diode) take over, which provide the battery with energy.

So, I can do wireless charging with my own hands?

Yes, it does not even require special knowledge in electrics. Moreover, already before us, enthusiasts conducted similar experiments, laying out detailed instructions and schemes for assembling wireless charging with your own hands. If all the necessary components are at hand, then creating the simplest wireless charging will not take an hour. However, we recommend that you first practice on the old “buttons”, and not run to “invent” charging for a brand new iPhone. For example, you can assemble such a thing for your Nokia, in which the charging socket has fallen off, reanimating it in this way. So let's get started.

Instructions: how to make a wireless charger for your phone with your own hands

The whole process can be divided into two parts: the manufacture of the transmitter and receiver. The first component will be a separate device, and the second will be installed in the phone.

The wireless charging circuit is very simple, it consists of two coils (transmitter and receiver), as well as a transistor and a resistor.

Transmitter device:
  1. To begin with, we take a frame, the diameter of which should be 7-10 centimeters, but another one is possible - at your discretion.
  2. Now you need a copper wire with a diameter of 0.5 mm. We wind it on the frame. It is necessary to make 20 turns, then make a tap and twist another 20 turns in the opposite direction.
  3. You need a transistor. You can use any, even polar, even bipolar - there is not much difference. If there is direct conduction, then you will have to change the polarity. The transistor is connected to the end of the coil and tap.
  4. We fasten the resulting structure with adhesive tape or other type of insulation. To make everything look “solid”, you can use boxes from a DVD or CD. Some craftsmen even bother by carving, so to speak, cases out of wood.
  5. To provide power, you can use a standard 5 volt power adapter that connects to the loop.
  6. Everything, the device that will transmit electricity is ready.
Now let's move on to making the receiver:
  1. If the manufacture of the transmitter takes a matter of minutes, then the receiver will have to sweat. First you have to make a coil, but already flat. You will need copper wire, but with a smaller diameter - 0.3-0.4 mm. You will need to make 25 turns. For convenience, I advise you to use some kind of lining, such as a piece of plastic. We gradually strengthen the turns with superglue so that the structure does not fall apart - you have to wind it again. At the end of the work, it is necessary to carefully tear off the receiver from the plastic on which it was wound.
  2. Now we connect our receiver to the battery through a high-frequency silicon diode, for example SS14. The coil should be on top of the battery, closer to the cover. A capacitor should be used to stabilize the voltage.
  3. You can connect the receiver either to the charging connector or directly to the battery. The latter option is perfect for users whose recharging port has “died”.
  4. That's it, close the back cover so as not to move the coil.

For many users, I think a video on how to make wireless charging with your own hands will not be superfluous. So here you go:

This DIY wireless charger is ready. To start using, just put the phone on the transmitter. To date, not a dozen instructions for assembling wireless chargers have accumulated on the Web. The principle is about the same, but enthusiasts continue to improve this device, introducing something of their own. True, it is better for beginners to practice for a start on the very simple version, presented in the instructions, so that you do not have to carry the phone for repair.

Suitable for any device

The most important plus of do-it-yourself wireless charging is the ability to make it for almost any device: a smartphone, a regular phone, a camera, a radio receiver, and so on. The principle of power supply of all these gadgets is similar, therefore, charging occurs according to the same scenario.

True, I strongly do not recommend trying to make wireless charging with your own hands for expensive smartphones. First, you will have to disassemble the case in order to connect the receiver coil, since modern models often made non-separable (it will not work just to remove the cover). Secondly, you run the risk of confusing something and ruining the device, especially for beginners. Thirdly, most modern smartphones support wireless charging from the factory or are provided by other manufacturers.

Cons of do-it-yourself wireless charging

do you need it?

Slowly we came to a very important point- cons of homemade wireless chargers. Yes, the opportunity to do something interesting and useful device- great, but let's not forget about the risks you take.

  • Errors during manufacturing will at best result in the wireless charging not working, at worst the phone will not work.
  • Don't expect your smartphone to charge quickly. Even factory wireless chargers still lag behind conventional chargers in terms of charging speed, to say nothing of DIY ones.
  • I don’t think that every house has a coil of wire, a diode and a couple of transistors. You will have to buy all this, spending an amount comparable to that required to buy a ready-made, albeit Chinese, device.

What can be added? Do-it-yourself wireless charging is rather a way to visually look at the principle of the electromagnetic field. To assemble a really worthwhile and beautiful device, you will need to spend a lot of time, and money. It is more profitable to order a ready-made kit without wasting time on winding the circuit. Of course, if you are a fan of creating something unusual with your own hands, then be sure to develop "your" wireless charger.


Photo: Koolpad Qi

And what about those who do not want to spend time assembling wireless charging with their own hands? It's simple - we order a ready-made kit, which is more or less qualitatively already assembled at the factory. The cost, as a rule, does not exceed 300 rubles, and the kit already includes both the transmitter and the receiver. Wireless chargers are sold in electronics stores, but it is more profitable to order from Chinese online stores.

Note that many modern smartphones are equipped with a receiver (receiver) by the manufacturer. Therefore, the owners of these models do not need to buy anything (in exceptional cases, sellers may not include a docking station (transmitter) in the kit). The list of such devices is quite extensive:

  • Samsung (Note 5, S6/S6 Duos and later)
  • Google Nexus 4/5/6/7
  • LG G3 and new flagships
  • Blackberry 8900
  • Nokia Lumia (810-930)
  • Yotaphone 2

The list includes the most common models, but not all. In addition, it is regularly updated with new devices. To find out if your smartphone supports wireless charging, look for the "Qi" designation in the model's specifications. Information must also be present on the manufacturer's website.

My smartphone does not support wireless charging

If your device has not received a built-in receiver, do not rush to get upset - the Chinese "friends" took care of the users by releasing both special for certain models and universal receivers. About the first type, I think everything is clear. Usually, they indicate which smartphone model it is intended for. But the second type of receivers is more interesting. Such receivers are not tied to a specific smartphone, so they can be installed in almost any. However, it should be borne in mind that universal receivers are divided into several classes:

  • Film with special contacts. Attaches under the cover of the phone without affecting functionality. The device must have contacts near the battery to install it. The main plus is that the charging socket remains free.
  • Apple receiver. This type is intended for Apple devices with a Lightning connector, that is, all current models.
  • Android receiver. Designed for smartphones with microUSB connector. Since Android smartphones are plentiful, and the manufacturer takes out the charging socket as he wants (and where he wants), you should look at the specific model. As a rule, microUSB is located on the bottom or top end, has type “A” (connector in the form of a regular trapezoid, if you look at the smartphone with the screen up), “B” (irregular trapezoid) or “C” (oval).

The docking station (transmitter) does not play a special role - you can even use it from more than one set or a completely different form. Therefore, the receiver and charging pad can be purchased separately, which will help save a little more.

In addition to receivers that need to be mounted on the cover or hidden under it, cases with a built-in receiver are available for sale. Of course, they are not universal, so you can’t pick up for every smartphone. And yes, they don't look the best. Be that as it may, many may still be interested in this view.

Models of wireless ready-made chargers

So, we come to buying a wireless charger on Chinese internet sites. You can, of course, go to an electronics store that sells better models, but you will have to overpay significantly. Therefore, we go to one of the stores on the Internet, where we are looking for something like "universal wireless chargers." Here you will meet a bunch of models. Next, you have several options:

  • Buying a complete set. In this case, you get both a receiver (receiver) and a charging pad. Upon receipt, all that remains is to connect everything.
  • Buying parts separately. You may already have a receiver and the docking station is broken (or vice versa). In order not to waste money, you can order only what you need.
  • Purchase of components for self assembly. Some vendors provide the basics (coils, boards, transistors, etc.) so that the user can build whatever their heart desires.

You can’t single out popular companies, since the sellers don’t even indicate them. And if the manufacturer is indicated, then the name says absolutely nothing (some Chinese company). Yes, and bother with the search good manufacturer stupid - the cost of wireless charging is usually ridiculous. Plus, customer reviews indicate that the marriage rate is quite low.


Content

There are situations when the mobile gadget is almost turned off, and there is no native charger at hand or there is no electricity. Then some knowledge will help solve this problem: a new invention is wireless charging, you can make it yourself. It is convenient to use, even if there is no auto charger nearby.

Is it possible to make a charger with your own hands

The answer to this question is positive. Anyone who has elementary ideas about the properties of wires and current can make it. Before you build a similar structure with your own hands, you need to take care of the availability of all materials - a diode and copper wire. Any plastic box, for example, from a CD, can serve as a case. You will also need transistors (bipolar or any other), preferably field ones - they will make the battery charge faster. All other tools are in each apartment, including glue and scissors.

How wireless charging works

The principle of operation of this type of charging is based on induction, the property of the coil to transmit electric current upon contact with the receiver. When connected to any power source, the device becomes a center of a perpendicular magnetic field. If you place two coils close to each other, one of them is connected to any power source, the second one will have a voltage of a certain strength and energy for the mobile phone. This effect is possible if these two coils do not touch each other in any way. Do-it-yourself wireless charging is a reality.

How to charge your phone

Almost anyone can make a portable wireless charger with their own hands, following the instructions. The whole process consists of two parts: the manufacture of the transmitter ( inner part) and receiver (outer part). The first of them is separate, the second is installed in the phone. The convenience of this solution is that you can always take the charger with you.

Transmitter device:

  1. In advance, it is necessary to prepare a frame with a diameter of 7 to 10 cm. Wind about 40 turns of wire on it (exclusively copper, whose diameter is 0.5 mm), not forgetting to make a tap in the middle after 20 circles. To do this, twist the wire, make a tap and continue winding.
  2. Connect a transistor of absolutely any rating to the end of the coil and to the tap. If a direct conduction device is used, then the polarity must be reversed when connecting.
  3. Install in a plastic box from under the disk or any other. Close.
  4. The device that transmits electricity is ready.

Receiver device:

  1. Unlike the transmitter, it has flat view. It consists of 25 turns, while the wire must be taken a little thinner, in the range of 0.3-0.4 mm. Gradually, the receiver needs to be strengthened with superglue.
  2. Separate the contour from the plastic base on which it was wound, using a knife.
  3. Connect it through a diode (high-frequency silicon is best) and attach it to the battery from above. A capacitor is used to stabilize the voltage.
  4. Connect to charging port. In some cases, this can be done directly with the battery, but the battery full sensor will not work.
  5. Close the back cover of the mobile phone. The receiver is ready.

To use the charger, the mobile phone simply needs to be placed on top of the transmitter. In this case, you need to monitor the sensor on the smartphone screen. There is another circuit of this device using a voltage amplifier and a resistor. Such do-it-yourself wireless charging can also revive a mobile phone without electricity, but it is recommended to use it only for experienced craftsmen.

The number of mobile communication devices in active use is constantly growing. Each of them comes with a charger supplied in the kit. However, not all products meet the deadlines set by manufacturers. The main reasons are the low quality electrical networks and the devices themselves. They often break and it is not always possible to quickly obtain a replacement. In such cases, a phone charger circuit is required, using which it is quite possible to repair a faulty device or make a new one with your own hands.

The main malfunctions of chargers

The charger is considered the weakest link that mobile phones are equipped with. They often fail due to low-quality parts, unstable mains voltage, or as a result of ordinary mechanical damage.

The most simple and the best option considered the purchase of a new device. Despite the differences in manufacturers, general schemes very similar to each other. At its core, this is a standard blocking generator that rectifies the current using a transformer. Chargers may differ in connector configuration, they may have different mains input rectifier circuits, made in a bridge or half-wave version. There are differences in the little things that are not decisive.

As practice shows, the main malfunctions of the memory are the following:

  • Breakdown of the capacitor installed behind the mains rectifier. As a result of the breakdown, not only the rectifier itself is damaged, but also a low-resistance fixed resistor, which simply burns out. In such situations, the resistor practically acts as a fuse.
  • Transistor failure. As a rule, many circuits use high-voltage high-power elements marked 13001 or 13003. For repairs, you can use the domestically produced KT940A product.
  • Generation does not start due to a breakdown of the capacitor. The output voltage becomes unstable when the zener diode is damaged.

Almost all charger cases are non-separable. Therefore, in many cases, repair becomes impractical and inefficient. It is much easier to use a ready-made source direct current by connecting it to the right cable and adding the missing elements.

Simple electronic circuit

The basis of many modern chargers are the simplest switching circuits of blocking generators, containing only one high-voltage transistor. They are compact in size and capable of delivering the required power. These devices are completely safe to use, since any malfunction leads to a complete absence of voltage at the output. Thus, high unstabilized voltage is excluded from entering the load.

Rectification of the alternating voltage of the network is carried out by the diode VD1. Some circuits include a whole diode bridge of 4 elements. The current pulse is limited at the moment of switching on by the resistor R1, with a power of 0.25 W. In the event of an overload, it simply burns out, protecting the entire circuit from failure.

To assemble the converter, a conventional flyback circuit based on the transistor VT1 is used. More stable operation is provided by the resistor R2, which starts generation at the moment of power supply. Additional generation support occurs due to the capacitor C1. Resistor R3 limits the base current during overloads and surges in the network.

Enhanced Reliability Scheme

In this case, the input voltage is rectified by using a diode bridge VD1, capacitor C1 and a resistor with a power of at least 0.5 W. Otherwise, during the charging of the capacitor when the device is turned on, it may burn out.

Capacitor C1 must have a capacity in microfarads equal to the power of the entire charger in watts. The basic circuit of the converter is the same as in the previous version, with a transistor VT1. To limit the current, an emitter with a current sensor based on resistor R4, diode VD3 and transistor VT2 is used.

This phone charger circuit is not much more complicated than the previous one, but much more efficient. The inverter can work stably without any limitation despite short circuits and loads. Transistor VT1 is protected from self-induction EMF emissions by a special circuit consisting of elements VD4, C5, R6.

It is necessary to install only a high-frequency diode, otherwise the circuit will not work at all. This chain can be installed in any similar schemes. Due to it, the body of the key transistor heats up much less, and the service life of the entire converter is significantly increased.

The output voltage is stabilized by a special element - the Zener diode DA1, installed at the charging output. Optocoupler V01 is used for.

Do-it-yourself charger repair

With some knowledge of electrical engineering and practical skills in working with tools, you can try to repair a cell phone charger on your own.

First of all, you need to open the case of the charger. If it is collapsible, you will need an appropriate screwdriver. With a non-separable option, you will have to act with sharp objects, dividing the charge along the junction line of the halves. As a rule, a non-separable design indicates a low quality of chargers.

After disassembly, a visual inspection of the board is carried out in order to detect defects. Most often, faulty places are marked by traces of burning resistors, and the board itself at these points will be darker. On the mechanical damage indicate cracks on the case and even on the board itself, as well as bent contacts. It is quite enough to bend them into place towards the board in order to resume the supply of mains voltage.

Often the cord at the output of the device is broken. Breaks occur most often near the base or directly at the plug. The defect is detected by measuring the resistance.

If there are no visible damages, the transistor is soldered and called. Instead of a faulty element, parts from burned-out energy-saving lamps will do. Everyone else did - resistors, diodes and capacitors - are checked in the same way and, if necessary, changed to serviceable ones.

Sent by:

The design of a home-made drive (PowerBank "a) of the "Vampirchik" type is described. A scheme and a description of its manufacture are given. In general, it is pleasant to read such materials, where the author takes the matter seriously.

Prologue

I was inspired to build this design by flying in an Airbus A380 aircraft, which has a USB connector under the armrest of each seat, designed to power USB-compatible devices.

But, not all planes have such a luxury, and even more so it cannot be found on trains and buses. And I have long dreamed of revisiting the series "Friends" from beginning to end. So why not kill two birds with one stone - watch the series and brighten up the travel time. An additional incentive for the construction of this device was the discovery of deposits of powerful lithium-ion batteries.

Technical task

The Portable Charger (MAD) should provide the following features.

1. Operating time in autonomous mode under rated load, not less than 10 hours. Li-ion batteries large capacity are the best suited for this.

2. Automatic switching on and off of the charger depending on the presence of the load.

3. Automatic shutdown memory when the battery is critically discharged.

4. The ability to force the charger to turn on when the battery is critically discharged, if necessary. I believe that on the road there may be such a situation when the battery of the portable memory is already discharged to a critical level, but it is necessary to recharge the phone for an emergency call. In this case, it is necessary to provide an "Emergency Start" button in order to use the energy still available in the battery.

5. Possibility to charge the batteries of the portable charger from the mains charger with Mini USB interface. Since the charger from the phone is always taken with you on the road anyway, you can also use it to charge the batteries of a portable PSU before the way back.

6. Simultaneous charging of the memory batteries and recharging of the mobile phone from the same mains charger. Since the mains charger from a mobile phone cannot provide enough current to quickly charge the battery of a portable charger, the charge can stretch for a day or more. Therefore, it should be possible to connect the phone to charge directly while charging the battery of a portable PSU.

Based on this terms of reference, a portable memory was built on lithium-ion batteries.

block diagram


Portable memory consists of the following nodes.

1. Converter 5 > 14 Volts.
2. A comparator that turns off the charge converter when the voltage on the lithium-ion battery reaches 12.8 volts.
3. Charge indicator - LED.
4. Converter 12.6 > 5 Volts.
5. Comparator 7.5 volts, turning off the charger when the battery is deeply discharged.
6. A timer that determines the operating time of the converter when the battery is critically discharged.
7. Converter operation indicator 12.6 > 5 Volt - LED.

Switching voltage converter MC34063


It didn’t take long to choose a driver for a voltage converter, since there wasn’t much to choose from. At the local radio market at a reasonable price ($ 0.4), I found only the popular MC34063 chip. I immediately bought a couple to find out if it was somehow possible to force the converter to turn off, since such a function is not provided in the datasheet for this chip. It turned out that this can be done if the supply voltage is applied to pin 3, intended for connecting the frequency-setting circuit.

On the picture typical scheme step-down pulse converter. Red indicates a forced shutdown circuit that may be needed for automation.

In principle, having assembled such a circuit, it is already possible to power the phone or player, if, for example, the power is supplied from ordinary batteries (batteries).

I will not describe in detail the operation of this microcircuit, but from " Additional materials» you can download and detailed description in Russian, and a small portable program for quickly calculating the elements of a step-up or step-down converter assembled on this chip.

Lithium-Ion Battery Charge and Discharge Control Units

When using lithium-ion batteries, it is desirable to limit their discharge and charge. For this purpose, I used comparators based on cheap CMOS chips. These microcircuits are extremely economical, as they operate on microcurrents. At the input they have field-effect transistors with an insulated gate, which makes it possible to use a microcurrent Reference Voltage Source (ION). I don't know where to get such a source You can try to use LM385 at 1.2V or 2.5V. Note ed.), so I took advantage of the fact that in the microcurrent mode, the stabilization voltage of conventional zener diodes decreases. This allows you to control the stabilization voltage within certain limits. Since this is not a documented inclusion of a zener diode, it is possible that a zener diode will have to be selected to provide a certain stabilization current.

To provide a stabilization current, say, 10-20 μA, the ballast resistance should be in the region of 1-2 MΩ. But, when adjusting the stabilization voltage, the resistance of the ballast resistor may turn out to be either too small (a few kilo-ohms) or too large (tens of mega-ohms). Then you have to choose not only the resistance of the ballast resistor, but also a copy of the zener diode.

The digital CMOS chip switches when the input signal level reaches half the supply voltage. Therefore, if the ION and the microcircuit are powered from a source whose voltage is to be measured, then a control signal can be obtained at the output of the circuit. Well, this very control signal can be applied to the third output of the MC34063 chip.

The drawing shows a comparator circuit on two elements of the K561LA7 chip.

Resistor R1 determines the value reference voltage, and resistors R2 and R3 comparator hysteresis.

Charger activation and identification unit

In order for the phone or player to start charging from the USB connector, it needs to be made clear that this is a USB connector, and not some kind of surrogate. To do this, you can apply a positive potential to the “-D” contact. In any case, this is enough for Blackberry and iPod. But, my proprietary charger also supplies a positive potential to the “+ D” contact, so I did exactly the same.


Another purpose of this node is to control the on and off of the converter 12.6> 5 Volts when a load is connected. This function is performed by transistors VT2 and VT3.

The design of the portable charger also provides for a mechanical power switch, but its purpose is more likely to correspond to the "mass switch" of the battery in the car.


Electrical diagram of a portable power supply

The figure shows a diagram of a mobile power supply.

C1, C3 = 1000uF

C2, C6, C10, C11, C13 = 0.1uF

C4, C5 = 680pF

C14 = 20uF (tantalum)

IC1, IC2 - MC34063
DD1 = K176LA7

DD2 = K561LE5

R28=3k

R5=30k

VD1, VD2 = 1N5819

HL1=Green

VD3, VD6 = KD510A

R8, R15, R23, R29 = 100k

VT1, VT2, VT3 = KT3107

L1=50mkH

R10, R11, R13, R26 = 1m

VT4 = KT3102
L2=100mkH

Are selected

R17, R19, R25 = 15k

R14* = 2m
R1 = 180

R22* = 510k

VD4*,VD5* = KS168A

Assignment of circuit nodes.

IC1 is a step-up voltage converter 5 > 14 Volts, which serves to charge the built-in battery. The converter limits the input current to 0.7 amps.

DD1.1, DD1.2 - battery charge comparator. Interrupts charging when the battery reaches 12.8 volts.

DD1.3, DD1.4 - indication generator. Makes the LED blink while charging. The indication is made by analogy with Nikon chargers. While charging, the LED flashes. Charging complete - LED is on continuously.

IC2 is a 12.6 > 5 Volt buck converter. Limits the output current to 0.7 Amps.

DD2.1, DD2.2 - battery discharge comparator. Interrupts the discharge of the battery when the voltage drops to 7.5 volts.

DD2.3, DD2.4 - timer for emergency switching on the converter. Turns on the converter for 12 minutes, even if the battery voltage drops to 7.5 volts.

Here the question may arise, why is such a low threshold voltage chosen, if some manufacturers do not recommend allowing it to drop below 3.0 and even 3.2 Volts per bank?

I reasoned like this. Travel does not happen as often as we would like, so the battery is unlikely to have to go through many charge-discharge cycles. Meanwhile, in some sources describing the operation of lithium-ion batteries, a voltage of 2.5 Volts is just called critical.

But, you can limit the discharge limit more high level voltage if you intend to use such a charger frequently.

Construction and details

Printed circuit boards (PP) are made of foil fiberglass 1mm thick. The dimensions of the PP are selected based on the dimensions of the purchased case.


All elements of the circuit, except for the battery, are located on two printed circuit boards. And on the smaller one there is only a Mini USB connector for connecting an external charger.

The PSU nodes were housed in a standard Z-34 polystyrene case. This is the most expensive part of the design, for which I had to pay $ 2.5.


The power switch pos.2 and the forced on button pos.3 are hidden flush with the outer surface of the case to avoid accidental pressing.

The Mini USB connector is displayed on back wall case, and the USB connector pos. 4 together with indicators pos. 5 and pos.6 on the front.

The size of the printed circuit boards is designed to fix the batteries in the portable PSU case. Between the batteries and other structural elements, a 0.5 mm thick electric cardboard gasket was inserted, bent in the form of a box.

And this is a portable PSU in assembled form.

Setting

Setting up a portable charger was reduced to the selection of instances of zener diodes and resistances of ballast resistors for each of the two comparators.

How to match resistors with high precision described .

Because portable devices are a necessity in today's daily life, they can be subject to overuse, improper charging, or normal wear and tear.

This article has an amazing idea on how to make with my own hands a simple portable phone charger. It will not be difficult and inexpensive to assemble such a device, for this you will need a soldering iron, flux, solder, a 9 volt Kron battery, a battery connector, a USB connector, an L7805 voltage regulator and, of course, a small box from Tic Tac, in which all the electronic stuffing will be placed. If you don’t dare to do homemade, then take a look at this Chinese store.

The voltage regulator has three wires. First, the entrance. The second is the mass, the third is the exit. The numbers 05 in the marking of this device mean that the output on it will be equal to 5 volts.

First you need the output of the stabilizer, and this is the right foot, solder to the plus of the USB connector. After that, we need to solder the middle lead to the negative terminal. In conclusion, we solder the wire with a plus from the crown connector to the first leg of the stabilizer. This is his entrance. The second wire from the crown connector, with a minus, is connected to the second leg of the stabilizer, that is, to the minus and to the mass.

Now all this can be placed in a tic-tac box. Let's test the portable charger. Let's make all the necessary connections. And we see that the charge indicator shows that the phone has begun to be powered by this autonomous device. Of course, such a charge will not last long, so for long-term operation you need to take a battery crown.

You may be interested in, which can be used as a device with the function that was described in our article.

DIY USB charger with MINTY BOOST

WE WERE LUCKY, that we live in a time when portable electronic devices allow us to do things that a spaceship full of science fiction writers could not even dream of a few decades ago. The only drawback of the iPhone, Nintendo DS, Kindle, etc. is their constant need to recharge. And it seems that no matter how careful you are to rise above it before the trip, you can always be off work at the most inconvenient moment. Sure, there are DC cables for the car, power plugs on commuter trains, and even USB charging plugs at airports, but there are millions of other places where you'll find you don't have fast charging options.

Admittedly, this is hardly even first world oh problem , but this is definitely a challenge for GeekDad who loves to solve problems.

Then what's the solution? Well, we could buy a bulk solution like Philips USB Power Station , but it's a bit expensive and seems like an easy answer. So what would McGyver do in this situation? Of course he builtMinty Boost charger !

Minty Boost Kit contains printed circuit board and all the parts needed to assemble a portable USB charger that runs on regular AA batteries. The kit requires soldering to assemble, which can be a problem for some. It is, however, a fairly simple project, andInstructions in AdaFruitfantastic. If you are looking for your first soldering project, this is a great choice.

I assembled my Minty Boost in about an hour and didn't even manage to burn myself for a change. Here are some examples of actions:

Once the main build was complete, it was simple to pop in a couple of AA batteries and test everything. When I first checked the output with a multimeter, the output was a bit low at 4.8V. This turned out to be due to the nearly dead AA batteries I was using. After I replaced them with new batteries, the output voltage was above 5.0V as expected.