I talked about choosing a tablet, and in particular about the function I needed, such as the ability to connect various USB devices to it, such as flash drives, a card reader (and, accordingly, memory cards of different formats), etc.
So, having bought a MoveO tablet! TPC-7HG I suddenly encountered a problem that was completely unexpected for me. The point is that of this tablet There is only a mini-USB connector. In itself, this was not a surprise or a problem for me - on the contrary - it’s easier to find a standard mini-USB cable in order to replace, for example, a broken one if necessary charging cable. An unpleasant surprise for me was that in my town nowhere - NOWHERE! - the mini-USB OTG cable was not sold! It didn't come with the kit either. Having gone to all possible and impossible stores, I came to the conclusion that, perhaps, it would be easier and faster to make such a cable with my own hands.
ATTENTION!!! EVERYTHING YOU DO IS AT YOUR OWN RISK!!!
And now a little theory. You cannot simply take and solder together a mini-USB plug with a piece of wire from one cable and a so-called USB-female plug from another cable. No, that is, of course, you can solder it, but just connecting it to the tablet and making it work with this cable will not work for any device. Here's the thing.
A standard mini-USB cable has a five-pin plug:
001.
The contacts in it are numbered as follows:
002.
But a standard USB cable has only 4 wires. Where did the fifth wire go? Nowhere. It simply does not solder to the connector ends!
The purpose and color marking of the wires in a regular USB cable are as follows:
1 - Red VBUS (+5V) +5 Volts DC voltage relative to GND. Maximum current - 500 mA.
2 - White D- (-Data)
3 - Green D+ (+Data)
4 - Black GND - common wire, ground, minus, 0 Volt
The main difference between a USB OTG cable is the plug. In a mini-USB OTG cable (as well as in a micro-USB OTG cable), pins 4 and 5 are closed to each other. In a regular (non-OTG) data cable, there is no wire soldered to the 4th pin of the plug. This plug is called USB-BM mini (micro). If you solder pins 4 and 5 together, then such a plug will be called USB-AM mini (micro). It is by the presence of a jumper between pins 4 and 5 in the USB-AM micro plug that the tablet determines what they are going to connect to it peripheral device. If this jumper is not present, then it itself will act as a passive device and will not respond to the connection of any kind of USB devices to it.
So, we have become familiar with the theory - let's start practicing.
We take a regular mini-USB cable and carefully open its connector with a utility knife. As a result, we get the following set of young technicians:
003.
Next we need to connect the 4th and 5th pins of the plug. This can be done, for example, by carefully cleaning the sealing plastic from the back of the connector. But here two unpleasant surprises await. Firstly, it turns out that this is not so easy to do without damaging anything, because the contact group is filled in conscientiously - you just have to pick it out. The second “surprise” is a short contact of the 4th contact (forgive me my pun!), which makes it extremely inconvenient to solder something to it:
004.
Having honestly ruined the first cable, I take up the second one, but I deal with it a little differently. Having opened and disassembled the mini-USB connector, from the back side of the contact pad, using the same stationery knife, I carefully scrape off the plastic in the area of the 4th and 5th contacts, right down to the contacts themselves:
005.
Now take a soldering iron and place a neat jumper between these two contacts with tin.
006.
The only thing you need to watch out for here is to keep the contact pad as flat as possible, both on this side - since in this case our connector may simply not fit back into its metal case, and on the opposite side (that is, actually from the side of the contacts) - since unevenness there can lead to bending of the contact group of the tablet socket, and this is already fraught. After making the jumper, you need to take care to avoid short circuiting the freshly soldered contacts with the connector body. To do this, I used such an indispensable tool as Poxipol.
007.
Please note that only TRANSPARENT Poxipol has electrical insulating properties. Metal Poxipol has quite conductive characteristics and, naturally, cannot be used in this case.
After Poxipol has hardened, the excess can be cleaned off with a knife and the USB connector can be assembled:
008.
In principle, it would be a good idea to fill it with Poxipol on top, but I recommend doing this after the cable has been tested for functionality.
And cut off the USB-female connector with a piece of wire from it:
010.
Now we only need to connect the two resulting cables (one with a mini-USB connector, the second with a USB-female connector) to each other.
First, we “dress” one of the wires with heat shrink:
011.
Take the soldering iron again:
012.
And we carefully solder (from the word “solder” and not “solder”!) the wires in the cables.
013.
To isolate the wires from each other, I used the same Poxipol. And when it froze, I covered it all together with heat shrink:
014.
The result is a cable like this.
The story is about how difficult it turned out to be to connect a 4g modem, flash drives and a mouse to the tablet, and even prevent it from running out of power. Disassembly, voltage tests, Orico cable, the item is good, I recommend it, not item 18. Everything is under cut)
Hello! Today we are reviewing a mcroUSB-OTG hub with additional power. There was already a review of it on Muska, but it was very brief, I’ll try to add more. It all started when I gave my parents a Prestigio Visconte Quad tablet (8"", Intel Atom Z3735G, 1GB RAM, 16GB ROM, Windows 8.1\10). It was exactly what was needed windows tablet so that the owners can use it as comfortably as possible, just like on their laptop in general. I bought the tablet from a friend, so the equipment was far from original: some kind of frivolous 1A charger and the first microUSB cable that came to hand. As a result, during active use (wi-fi, online video, bluetooth mouse), the tablet was discharged while charging. Moreover, the 4g modem connected via an otg cable did not start; it appeared in the system, then fell off again at the stage of installing the firewood. Thanks to the community on 4pda, I found out that the modem simply does not have enough current. And a whole book is devoted to the problem of surviving with one microUSB. And I started making cables with additional power according to 4pda diagrams.
Scheme using scotch locks
Option with hub
Everything worked, the modem started up, but using such cables was inconvenient, and the design itself did not last long. It was decided to kill all birds with one stone and purchase a factory version and the choice fell on Acasis H-027. I immediately liked its strict design and the modest but original Acasis marking, which looks as if it had Asus written on it, I would not have doubted it at all. I chose the cheapest lot at that time and received it 37 days later. There were no instructions included (although some people do). All packaging is bubble wrap and a bag.
The device can operate in three modes:
1. Charging only
2. otg+charging
3. OTG only
There is a switch to switch between them.
On my tablet these modes worked like this: 1. otg+charging
2. otg+charging
3. OTG only
The body of the device consists of two halves, fastened using the tongue-and-groove method. When disassembled, the spikes suffer and heroically fall off. Everything inside is clean and tidy.
The hub is controlled by a fe 1.1s microcircuit, very cheap, it can be found in many USB 2.0 hubs from Ali, from very good models to copies that literally fall apart in your hands. Often found in inexpensive Chinese tablets.
The indicator light indicates that power is connected. It's not very well implemented - just a hole in the body.
The Otg mode works flawlessly, I didn’t measure copying speeds from drives, everything is normal there. “OTG+charging” mode with Orico colorful 0.5m cable
with three flash drives
with screw and flash drives
With the 4g modem, everything is also correct. Basically, to power the tablet and hub, I use a Robiton charger and an Orico microUSB cable 2 m long.
In the maximum possible option: charger + 2 meters of cable + hub with screw, modem and mouse, the tablet charges slowly, but it charges, otg works, i.e. The hub is fulfilling its purpose. Nevertheless, we will take measurements.
without hub with 1A load
with hub and 1A load
Not all old tablets support the function of connecting a flash drive or modem, but I will tell you how to outsmart them and connect a flash drive, modem, and even HDD.
Today I would like to present to your attention an OTG adapter.
First, I want to tell you what OTG is? This is a way to connect to your tablet or phone that supports OTG function, printer, flash drive and even hard drive. This connection is also called USB-host.
You can also connect a keyboard or mouse to your gadget, if the gadget supports such a function.
And so, to create this miracle cable, we need:
Old USB extension cable
Micro USB connector (you can get it from a regular USB cable for your device)
Soldering iron and soldering accessories
And so, let's go, to make such a cable, we will need to connect the 4th pin to the 5th pin of the micro USB connector
We must get to the fourth pin and connect it with a jumper to the GND wire as shown in the picture
After we connect the 4th and 5th contacts with a jumper, our gadget will perform the function of an active device and will understand that another passive device is about to be connected to it. Until we install a jumper, the gadget will continue to act as a passive device and will not see your flash drives.
But that’s not all; to connect a hard drive to a phone or tablet, this adapter will not be enough for us. To connect devices whose consumption is more than 100mA, namely 100mA can be supplied by the port of your device, we will need to connect additional power to our OTG cable, which should be enough for your hard drive to work.
Here is a diagram of such an adapter
Now it's time to start collecting
We take an old USB extension cable and cut it not too far from the 2.0 connector, since the current is only 100mA, to avoid large losses. Cut approximately in the same place as shown in the photo
Afterwards we clean our wire
I connected pins 4 and 5 with a drop of solder.
Well, here is our entire cable assembled
All that remains is to check the functionality, take the tablet, insert the “adapter” and insert the flash drive into it, everything works, as the flashing LED on the flash drive and the tablet detecting the flash drive tell us.
If you have a spare USB flash drive, you can easily convert it into an OTG-USB drive so you can connect it to your smartphone or tablet without having to carry a USB-OTG adapter. Of course, you can just buy such a device on the Internet or in a store, but I would like to make my own, since it is easy and I have all the necessary components and the OTG cable diagram.
There is a risk of damaging your flash drive or smartphone/tablet; be careful when laying and soldering wires; if possible, it is better to test it on a cheap smartphone for the first time. I warned you.
To desolder OTG you will need:
- Regular USB 2.0 flash drive with solder connector (free)
- USB-OTG adapter (should cost less than 100 rubles)
- Multimeter with continuity test function
- Soldering iron with solder
- Basic soldering and multimeter skills
- Knife (to open flash drive)
- Silicone caulk, Sugru (rubber clay), hot glue or insulation glue
- Cutting tool
- Electric drill or Dremel with 2mm bit
- (Optional) USB connector (male) type-A for checking pinouts
Step 1: Select a suitable USB flash drive
The first thing you need to do is choose a flash drive with a solder connector. Not all USB drives are the same and the only way to find out is to open it. Use a knife or screwdriver for this.
[Photo 2-5] is a Chinese flash drive in a stainless steel case. As you can see, this ultra-thin flash drive is filled with plastic, there is no solder connector.
[Photo 6-8] - another flash drive from China. She has a board with a connector, I will use that. Please note that the “dirty” solder in the connector is due to the fact that I already soldered this flash drive.
Step 2: Cut the USB-OTG adapter
Show 4 more images
[Photo 1-2] On my USB-OTG adapter model, I can simply pull back the frame of the USB port to show you what's inside.
[Photo 3-5] Measure the length of cable required for your USB drive. Don't cut the cable too close to either end, we'll need both. The yellow flash drive is just an example.
[Photo 6-9] Using a cutting tool, carefully open the wire and separate the inner four wires. This must be done so that they can fit inside the flash drive when you assemble it.
Step 3: Check the OTG adapter pinout
Currently, USB-OTG adapters use 4 wires. Two are for power and two are for data. You need to make sure you're soldering the right wire, otherwise you could damage your $500 smartphone over a $2 project.
Using a multimeter and the USB connector (female) that we just cut off, we can determine the pinout of the OTG cable. Usually the colors are: red, white, green, black, but not always in that order, and maybe not at all, you will have other colors.
Pay attention to the OTG pinout diagram, which in the photo, if you use the input connector (female), then the order of colors will be reversed!
[Photo 4-5] I used the USB male (output) connector to make testing easier. On the Internet it costs less than a hundred rubles.
[Photo 6-7] This is the reading from my multimeter when it is in continuity mode. Pay attention to the correct orientation of the wires and connector. Double check the order and refer to the USB pinout diagram if in doubt.
Step 4: Soldering
Now it's time to solder the wire. Prepare your soldering iron and solder. Solder all 4 wires.
DOUBLE CHECK THAT THERE IS NOT A SHORT CIRCUIT on one of the wires you just soldered. Also make sure that the wires are not too close to each other. At the current stage, it is impossible to check the correctness of the pinout, so if you feel that you have made a mistake, it is better to stop than to damage your smartphone or tablet.
Step 5: Prepare and assemble the body
[Photos 1-3] This is a simple step. First you need to drill into the housing of your USB drive. This is done so that the OTG cable can come out of the back of the flash drive. I used a 2mm drill bit, but I think a 3mm would have worked better.
[Photo 4-6] Next step you need to make sure that the insides of the flash drive do not move. Each time you open it and put it back together, there is a chance that the former tightness of the assembly will disappear. So I decided to use double-sided tape to prevent anything from moving. You can use Blu-tack, Sugru, hot glue or anything else.
I also covered the wires near the connector with silicone sealant so as not to worry about them touching each other and causing a short circuit. It's not necessary to do this, but I highly recommend it. I don't know if Sugru or Blu-tack have insulating properties, but if you're in doubt, silicone caulk and hot glue work great.
Step 6: That's it!
Show 5 more images
When the work is finished, let's first insert the USB OTG drive into the computer. The reason I chose a computer is because motherboard Most computers have short circuit protection.
Then I checked the drive on the tablet, via USB port and OTG. Everything worked great. In the end, I inserted it into my Android smartphone (LG G4), everything still worked fine, the device was displayed in file manager. Keep in mind that most Android devices do not support file storage. NTFS system, so it’s better to format the flash drive in FAT32.
Here you go! Homemade OTG-USB drive works! Moreover, it was very cheap!
I would like to warn you that since this is a simple "parallel" wiring, NEVER ATTEMPT TO CONNECT BOTH ENDS OF THE DEVICE [PHOTO 7].
[Photo 8-10]. Now you know how to make your own OTG USB drive. Here are photos of my homemade OTG hub. It is made using the same disassembly and soldering method, even the cable is the same. I've been using it for over a year without any problems.
Almost any manipulator is connected to a computer using a special USB cable, thereby turning into an information input device. This allows you to create an entire ecosystem of various devices, but what if you just need to connect a keyboard to a tablet or smartphone?
For this, there are otg cables, which in fact are just cleverly named adapters between micro-usb and usb. Allowing you to connect mice to the same smartphones and, using additional software and drivers, use them freely, without restrictions. Such a cable for connecting external manipulators costs from a couple of dollars to ten, depending on the manufacturer, the quality and number of devices connected at a time. AND main question our layman: how to make such a device yourself, so as not to waste money? Fortunately, all you need is an old charger and an unnecessary connector, as well as pliers and electrical tape.
In fact, such a device does not have any complex microcircuits or adapters; all configuration of the controller occurs through the internal software of the tablet or phone, so it is just a cable with an input and output that can be made in 10 minutes. And yet, how to make an otg cable with your own hands if you only have an old smartphone charger? Why is it necessary to connect external manipulators to mobile devices, and how to deal with differences in the current strength of devices? And what do you need to know about otg before using it?
Methods of application
Before you pick up a soldering iron, you should understand why you need such a cable at all? After all, there are a lot of keyboards for the same tablet, specially created and designed for ease of use, not to mention gamepads and mice. Is this really an ordinary adapter for those who cannot afford such a “zoo” of information input devices? In fact, it's much more universal device, because micro-usb is used in the same powerbank, and the phone or tablet itself has enough powerful battery becomes a separate device for recharging. So, you find yourself in a situation where the laptop is almost dead, but the phone is 100 percent, this is where otg support comes in handy.
Yes, 2-4 batteries thousand mah that won't last long. But if we are talking about urgently answering a letter or sending a project to the authorities, the time is already counting in seconds. In addition, the opposite situation is also possible, and with the help of such adapters you can always give part of the charge to a friend with a discharged smartphone. But before you start happily cutting off the nearest old charger, make sure you have a soldering iron and tin. In fact, the same OTG can be called usb-c cable– micro-usb, which is simply necessary for owners of new equipment from Apple.
How to find out if your device supports OTG cable
And now in front of you there is already a pinout and a heated soldering iron, but it remains to check the last point, is your device even capable of supporting such connections that allow you to transfer battery charge? Or connect third-party manipulators to it? This depends purely on the version of Android and partly on the modules built into the accessory, but to simplify your life, there are many testing programs that allow you to determine in a matter of minutes whether the phone is suitable for these purposes. As already mentioned, if this is not the case, try updating the firmware version and downloading drivers for the required accessory and you will be happy.
What tools will you need?
Those who did not miss labor lessons at school already have a rough idea necessary tools to create a cable. We only need to cut off the input and output from different charges and connect them together using soldering and then electrical tape, so take:
- Wire cutters or pliers, and you have to be very careful here. Any extra spikes degrade the communication speed between devices, increasing resistance and decreasing current accordingly.
- Use a knife or the same pliers to strip the insulation, although you don’t need to remove it completely, as some craftsmen do, a small piece of bare wire is enough, this way you will reduce the chance of breaking the chain.
- Soldering iron. It doesn’t matter whether you have a Soviet device in your hands or a modern soldering iron with automatic shutdown when touching living matter. Remember the safety rules, hold it correctly. With some skill, you can also use a wood burning device. But this will take a little longer and will leave traces of the oxidation process on it.
There are several tricks that will allow you to do without a soldering iron, which every Soviet child knows about. It is enough to use any filament or thick enough copper wire and heat it separately, while insulating it from direct contact with the skin. But if you have never even held a soldering iron in your hands, it is better not to risk doing it yourself without the help of a specialist.
Do not forget that the device cools down for several minutes after use and try to prevent rosin and tin from getting on the table, especially if it is made of flammable materials. Try not to get burned; you can buy special protective gloves for this.
Soldering
To start homemade cable should be cut according to the prepared pattern. Measure the required length and do not try to make it as long as possible, this may lead to inconvenience in use. Then strip the wire of insulation, do not remove too much, this way you will increase the stability of the connection and reduce the chance of “fractures” in the joint. And you shouldn’t waste a large amount of tin. The neater and more inconspicuous the connection, the greater the strength of the adapter and the speed of charge transfer, and when the current is measured at 1 A, there is no need for extra resistance.
Having soldered and made sure that the metal has frozen, rewind the exposed wire with electrical tape; again, a hundred layers will in no way affect the strength of the structure, so excessive fanaticism should be avoided here.
Examination
After installing all the necessary software and drivers on your phone, try the adapter; if it does not work, check the current using an ammeter. Is there current? Then the problem is directly in the smartphone, try testing your homemade product on another accessory or on a different firmware version!
Video instruction
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