I have many devices using USB Port for charging. For this, I purchased one USB Hub to connect 4 devices at a time. But the result was disappointing . The devices are not charging and even a Pen drive is not opening in the Hub. Analyzed the reason and found that the USB port of Laptop is not giving sufficient current to the devices for charging. The USB.2.0 Port can give maximum 200 mA current and USB.3.0 can give maximum 400 mA current. Then how all these 4 devices in the Hub charge normally. The 200 mA current from the Laptop port is sharing to all devices, so no one is charging. Moreover, the Laptop gave a warning that, “USB Port over loaded and shutting down”. Remembered that famous saying “Every problem born with its own solution”. Got the remedy. If the current to the USB Hub is increased, all devices will charge normally. But in that case, Laptop is not useful and I have to make a separate power supply. So made a USB Wall socket. It has an AC socket for charging Laptop, and a 5V, 1 Amps SMPS power supply to power the USB hub. Thus the problem solved. The USB Wall socket is fixed on the wall and powered from Mains. SMPS has well AC-DC isolation, so no shock hazard while charging the USB devices. I found the same type of USB Wall socket in the Online shop but its cost is Rs.2500. I made it at the cost of Rs.250. Let us check it.
Warning. This Project has High volt AC component. So construct only if you are experienced to handle high voltage circuits otherwise leave it.Take all precautionary measures to avoid Shock Hazards.
You need the following components
Purchased one Adapter type SMPS power supply. It is rated 5V at 1 Amps. Its cost was Rs.100. Removed the cover and hacked the power supply board. It is an SMPS power supply with AC-DC isolation. It can be connected to 220V AC and it gives 5V, 1 Amps current as output. So it is an ideal one to power the USB hub.
The USB Hub is the one with the provision to give external power. It has 4 USB sockets to use four devices simultaneously. It is actually for charging as well as for using the USB devices. For this, it has four wires. Red (Positive), Black (Negative), White (Data In ) and Green ( Data Out ). But since the Hub is using only for charging, these wires are not required. So removed the wires. The PCB of the Hub has a DC socket to give external power. Connected the DC output from the SMPS to the positive and negative points of the Hub DC Socket with correct polarity.
Well, the SMPS is powering the USB Hub.
Fixed the three pin socket in the switch box. There is sufficient room in the box to accommodate the SMPS also. Connected the AC lines to the three pin Socket. To the same points, connected the AC side of SMPS. To get AC on LED indication, used a Red LED with 56K 1 Watt series resistor. So the LED is directly powered from AC. The Green LED is connected to the DC out of SMPS with 1K series resistor
Everything connected. The wires are secured using Tie to prevent accidental wire pulling and detachment. This is necessary , because if a detached wire from AC side makes contact with the DC side, it will cause shock hazard. Now there are two bare points carrying AC. These are the Pins of the three pin socket. These also made shock proof by enclosing inside plastic sleeve.
Applied Glue to all loose points to make everything intact. So no wire, LED, resistors etc will detach from the box. Also glued the SMPS in the box.
Now the USB Wall Socket is ready. It is powering the USB Hub with sufficient current.
Power meter showed that it is 0.96 Watts without load
It also consumes 9 mA current without load.
Connected 4 devices in the USB Hub. A Mobile Phone, MP3 Player, 1 Watt LED light and a 2.4V Battery for charging. All are charging properly.
With load, the USB Wall socket is 9.19 Watts. It takes around 42 mA current. This is the AC side shown by the Power Meter. But the DC side is 1 Amps current.
Now gave some touching to its outer side to give a good look.
Now the USB Wall Socket is ready on the wall. It can very well charge any USB device that requires 5V. This is necessary because if we forget to charge the devices, the Lithium Ion battery in these devices will damage permanently. So we have to allow the battery for its normal charge / discharge cycles.