Hi all. I purchased a kit on a Chinese website for wireless transmission energy, also called wireless charging. Certainly, this device You can assemble it yourself; there are plenty of wireless charger circuits on the Internet. But I wanted to purchase a complete device, offered to us as a DIY device. Use as wireless charging For mobile phone, I didn't mean to. But in robotics, I saw clear advantages over wired chargers.
The device you created in robotics can independently assess the battery charge and, if necessary, independently recharge. For example, a robot only needs to approach the charger at an appropriate distance and the charging process will begin. Very convenient, the robot wants to stay in working order and let it take care of itself.
Wireless charging consists of two parts, a receiver and an energy transmitter.
The transmitter supply voltage is twelve volts, while the receiver output is five volts. The stated maximum charging current is six hundred milliamps. Additional documentation was not on the website. After scouring the Internet, I found the following information. The receiver uses a T3168 chip
Unlike the receiver, the energy transmitter is, so to speak, filled with a compound. Accordingly, it was not possible to get to the board. The documentation for the receiver included a response circuit for the transmitter.
But I still got to the board (using a hammer), as it turned out, the circuit is different. There were two microcircuits installed on the board, without any markings. We were able to obtain scant information about the mysterious micro-assemblies on the forums. I found out that these are two powerful transistors switched on in high-frequency generator mode. Subsequently, I found out that you can also buy an open board without filling.
As for the charging current. The wireless charger, as I already said, allows you to charge the battery with a current of up to 600 milliamps. But we will receive this current only in the immediate vicinity between the circuits. The table shows the relationship between distance and current.
Wireless demonstration charger and a number of others I filmed. In general, I liked the module. In the future I am going to use a wireless charger in my project.
Today more and more more smartphones Support wireless charging, out of the box or via update hardware(special back cover). But there's no reason why all other USB-chargeable devices shouldn't have this luxury.
In this tutorial I will show you how to wirelessly charge your smartphone (I demonstrate on Samsung Galaxy S II) or virtually any device that charges via USB (of course, I can't guarantee that this will work on every device, but I see no reason why it shouldn't work, other than various technologies blocking such an option) .
Step 1: Background and Explanation
***FOLLOW THESE INSTRUCTIONS AT YOUR OWN RISK***
Use precautions and don't do anything you're not sure about.
I am not responsible for any damage to your device or yourself.
There are several projects on the network about homemade wireless charging. I took a little bit from everywhere and added some of my own ideas.
The entire concept and basic design is based on Palm technology (although there are other manufacturers offering similar solutions). Touchstone is a Palm charging dock designed for the Palm Pre smartphone that supports wireless charging via a separately sold back cover.
There are several wireless charging technologies produced by different manufacturers, which use the same physical concept, but they are not cross compatible, you can't use different receivers and docks (I checked).
I won't bore you with the physics behind the concept (although it's quite interesting), and I won't tell you anything new that hasn't already been said by others and more professionally, so if you want, you can google "DIY wireless charging" and read about it.
Step 2: Assembling the Components
Components and tools required for work:
- Palm Touchstone - about 1000 rub.
- Wireless charging coil - about 500 rub.
- A small piece of thin wire
- USB charger (more than 1A) (doesn't have to be original Palm, but cheap Chinese ones won't work, I work with a 2.1A charger from an iPad) and USB cable.
- Case\back cover\cover for battery with increased capacity (without battery itself)
- Soldering iron and soldering accessories
- Multimeter (specifically, we will need a voltmeter and a continuity tester)
- A screwdriver that fits the screws on your device.
- Insulating tape
- Wire stripper and cutter
Step 3: Check the functionality of the components and replace them if necessary
Before you start taking your phone apart, make sure the components you have are working.
First, connect the Touchstone to the charger and place the coil on top of it with the metal sticker facing up.
Measure the voltage between the coil contact points, you should get a value between 5.2V and 5.5V.
This does not mean that your phone will charge - there is a caveat (the following is information that was difficult to find):
Touchstone appears to only work with chargers with the fast charging. An indicator of this is that pins 2 and 3 of the USB cable are shorted (+ and - data pins), so make sure your charger can supply more than 1A and you need to sacrifice the USB cable for this - take the cable and remove its outer insulation, leaving the wires intact (no need to cut the cable).
Cut the green and white wires and strip the ends. Twist them together and solder them (you only need to do this on the Touchstone side, no need to cut both sides)
Cover everything with electrical tape.
Keep in mind that the cable is now much more fragile and you may break it if you pull it a little.
Note also that some chargers simply don't work (I tried a Chinese 1000mA RUR 60 charger and the Touchstone didn't work with that - while plugging directly into the phone worked fine), so use a good charger device specifically for your battery.
See photos for detailed USB port pinout, this may also be helpful in the next steps as I won't explain some of the things I use (specifically ground and +5V)
Step 4: Explore your device
Carefully disassemble the device (if you are not confident, there are many disassembly instructions for almost every device) and find the +5V pin on the USB port and follow it to find a convenient place for soldering (of course, unless you are a super professional who may be soldered to tiny pins on the connector itself). Don't worry about grounding, every piece of metal here is grounded.
In my case (Galaxy S II), disassembly was not difficult: 7 screws and a fingernail, and it was open.
Finding a place to solder was a little more difficult. It should be a place with enough room for the wire and not too small or delicate to burn or damage the contact.
I used the capacitor shown in the photo (used using Google and a multimeter when searching for it).
Once you have found your solder spot, try to find the best path for your solder, it should short the + from the coil and + to the USB.
In my case, I decided to work with copper foil because I didn't have a wire running along the entire device, and foil is quite easy to work with.
The main consideration for me in choosing the route was that I wanted the phone to look (almost) unchanged from the outside, and all the individual parts to remain separate (I didn't want the cover and board connected by a wire that would constantly dangle).
Looking for land:
- Almost every piece of exposed metal must be grounded.
- You can use a continuity tester to see if the specific detail or not.
- It doesn't matter what you connect to as long as it's grounded.
- Choose a detail that will make your design as simple and neat as possible.
- If you can't find a grounded piece of metal, you can connect to the ground output of the USB port.
Step 5: Choosing a Weapon
The choice of conductive material is critical. Not for performance, but to properly close your device. Smartphones and other electronic devices in general are becoming more and more compact thanks to more technologically advanced components. Because of this, it's getting smaller inside. free space, so finding conductive material is our main task.
I recommend using adhesive copper foil. I found that the glue was quite strong but non-conductive, so simply placing foil on top of the other piece was not enough to complete the circuit. This means we have two options:
- Do everything in one long piece. This method is more difficult because you need to carefully fold and flatten the foil without overlapping or tearing it. The difficulty is that it is quite thin.
- Use multiple parts and solder them together. This method is a little easier and doesn't require super precise motor skills, but you still need to be careful not to use too much solder and also not to heat the area too much to avoid melting the foil.
Naturally, you can use regular thin wire.
Using copper foil creates another problem - it has no insulation. I decided to just use duct tape. The layer should not be too thick. You can cut the electrical tape and choose which area you want to cover (which is much more difficult when using insulated wire).
Step 6: Lay the foil (or wiring)
Show 6 more images
You can see in the photos that my system consists of 3 separate parts that are connected by contacts. I did this because, as I mentioned earlier, I wanted all the individual pieces to remain separate.
On the device itself, the wire connects the + to the USB (via a ceramic capacitor, which you can see in the photo) and the copper foil, which serves as a contact for the next part.
On the back housing is a single layer of copper foil running from the top of the speaker (that is, the contact that connects the first part) to the top right corner of the battery compartment - this is the only part visible from the outside of the device, and this will be the contact for the next part.
On the back cover there are a couple of pieces of copper foil running from the charging coil wires to their corresponding contact pins (the part of the foil sticking out of the battery and the ground plate that holds the SIM card in place - this is our ground)
It doesn't really matter how you do it, just make sure the device closes properly and that you're not shorting anything.
Step 7: Plan A - installing the coil under the back cover
Plan A implies that there is a Plan B. Indeed, there is one.
I decided to show you this unsuccessful attempt to install the charging coil and its circuitry under the battery cover, since it can be installed on other devices and even on the same extended battery cover.
There seems to be no room between the battery and the cover, not even for the coil circuit.
Placing the charging coil is not that difficult, just make sure there is a place where you install it and that you are not shorting any circuits (the coil and its circuitry are completely exposed).
The trickier part is placing the small metal discs correctly - I came up with an easy solution:
Take the cap and spool and place them on the magnetic docking station.
The coil may have a slight magnetism, but this should be enough to prevent it from moving too much.
Now take the metal discs and place them on the four corners around the coil, they will snap into place thanks to the magnets in the docking station.
Move the cover so that everything is properly aligned - the disks should slide over the cover and remain in the same place relative to the docking station. Center the coil between the discs.
Take the metal sticker that came with the coil and place it on top of the coil (this is important for it to work)
Secure the discs in place with electrical tape.
Now you can remove back panel from the docking station and use copper foil to cover the circuit and make contacts.
Step 8: Plan B - use a regular case
Plan A, unfortunately, went up in smoke (I wanted to use the aluminum bumper as protection for my phone, but for this I need to use the original cover).
Plan B uses a plastic case without a battery cover. It's not ideal (especially the lid I used), but it works.
If I could find an extended back cover for the Galaxy S II (without battery) on sale, we'd be back to plan A.
It's a good thing that with Plan A I did most of the work for Plan B because everything is held on tape and I can just take it off and move it to another enclosure.
All that remains is to make sure that there is contact. The case has more space between it and the phone (when the back cover is removed), meaning there is more space between the contact points.
I solved this problem by folding copper foil and soldering it to the contact point to fill the gap. This wasn't enough, so I simply filled the remaining gap with solder. (see photo)
Step 9: Final Assembly and Troubleshooting
Reassemble the phone and try to charge it.
If it charges, you're done.
If not, try the following:
- If there is no sign of charging, check your contacts. Make sure the circuit is closed. Use a continuity tester.
- If the charging light turns on and off, there could be a problem with the charger or cable. Try different chargers and cables.
- If your wiring runs under or over any components that also have contact points (like the speaker on my Galaxy S II), make sure they are working, you may have created a short between the contacts - that's what happened to my speaker. I opened the phone and slightly bent the contacts using a flathead screwdriver. Now everything works fine.
Smartphone manufacturers compete with each other, equipping each new model with some unique feature. This is how phones with the function became available to users. Convenient, fast, it promises maximum comfort when working with the gadget. But, as a rule, it does not come with a smartphone. The cost of the cheapest model starts from 700 rubles, a more or less normal one will cost 2.5 thousand rubles. And of course, the user has a logical question: how to make wireless charging with your own hands? It turns out that if you want and have some details, this is quite simple to do, but first you need to familiarize yourself with all the accompanying nuances.
A wireless charger allows you to charge your phone without connecting it to wires. The mobile phone is placed on a special stand, where the whole process takes place.
The operating principle is to transfer magnetic field from transmitter to receiver. The second one in this case begins to generate voltage, which charges the battery.
The presence of a built-in receiver can be seen in the specifications; if the manufacturer has indicated support for the Qi standard, then everything is in order.
ATTENTION. The lack of a built-in receiver in a gadget is not a reason to abandon the idea. In this case, the smartphone owner simply needs to put in a little more effort and make the receiver himself.
How to do wireless charging yourself?
There are several options for performing the work, the essence of which ultimately comes down to one thing. If you place all the elements on a clean board, attach them with a soldering iron and equip the structure with a choke, you can get high quality device. It will be capable of delivering voltage up to two amperes, operating reliably and uninterruptedly. However, if you have a minimum of materials at hand, it is worth using a simpler scheme. To choose the most suitable option, it is worth considering both.
Transmitter: option No. 1
Before making a reliable and high-quality wireless charger with your own hands, you need to prepare:
- fee;
- a choke with a wire diameter of 1 mm, wrapped in 5–10 turns;
- resistors rated up to 1 W - 2 pcs.;
- transistors with a voltage of 10 volts and more - 2 pcs.;
- UF diodes - 2 pcs.;
- film capacitor with a capacity of 0.35 to 1 µF;
- multimeter;
- soldering iron and soldering accessories.
First of all, a circuit is made from a long wire. To do this, the wire is folded in half, using fingers or a contour with a diameter of 5–10 centimeters, 5 turns are wound. Along the entire circumference, the contour is firmly fastened with tape or glue.
Next, you need to cut the loop resulting from folding the wire in half, you get 4 free ends. They are cleaned, the beginning of the first winding is connected to the end of the second, and the end of the first winding is connected to the beginning of the second. A multimeter will help you determine which end should connect to which. The “active” ends are soldered together, forming a midpoint. It is she who will go to the plus of the power supply through the inductor. Resistors will later be connected to the free ends.
Assemble for a phone with your own hands in the following sequence: solder two transistors, then diodes to them, and resistors to the diodes, in turn. The ends of the latter are distributed between the board and diodes. The circuit is soldered last, and both windings are pre-tinning.
A do-it-yourself smartphone transmitter assembled in this way creates a high-frequency field on the primary circuit, which is smoothed out by a capacitor on the secondary circuit and stabilizes to approximately 5 volts.
Transmitter: option No. 2
The second option will tell you how to make wireless charging for your phone more in a simple way from a minimum of materials. You will need:
- copper wire with a diameter of 0.5 mm;
- two transistors.
The wire is wound in forty turns per frame. It must be prepared in advance, based on the optimal diameter of 7–10 centimeters. After the twentieth turn, layering is done. A resistor is connected to it and the end of the coil, at which point the device is considered ready.
ADVICE. It is worth considering the conductivity of the resistor; if it is direct, the polarity must be changed during assembly.
The transmitter should be placed in a housing; a disc box is perfect for its role.
Receiver
If the smartphone is not equipped with a built-in receiver, then you will need to spend time making one. You can install your receiver not only on a smartphone, but also on a regular push-button one, since it is connected to a battery.
Do-it-yourself wireless charging for a smartphone in this case will require a wire with a diameter of 0.3–0.4 mm. Double-sided tape and superglue will also come in handy. For convenience, work on creating the contour can be done on a plastic surface.
The receiver consists of 25 turns, pressed tightly together. To prevent the structure from breaking in the future, it is recommended to fasten the coils with double-sided tape and, as the area increases, fill them with superglue.
In addition to the wire, the receiver includes a silicon diode, the marking of which does not make much difference. The turns of the second part are carefully separated from the surface and connected to the device through a diode.
In addition to how to make wireless charging, it is worth thinking about how to connect it. The receiver can be connected either to the battery or to the charger connector. The second option, as practice shows, is more preferable.
All that remains is to attach the made receiver to the cover of the smartphone and you can start testing.
IMPORTANT. To check the functionality of the wireless charger, you should take old phone, the loss of which due to errors in the assembly will not cause damage to the owner. It is also not recommended to charge a phone that is under manufacturer’s warranty in this way.
What is worth knowing about homemade charging?
Before you learn how to make wireless charging yourself, you should know the following:
- A homemade device without the proper quality and compliance of design elements will not have much power. Therefore, charging time can increase to 7 hours.
- The charge occurs at a distance of 4 centimeters; the gadget must lie directly on the transmitter during the process.
- With the right approach to creating wireless charging, you can get a truly excellent accessory that will help out if the standard charger or input breaks down!
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