USB as pwr sply

[Faisal__saf]

I have a small radio(3v) and i listen to if about 12 hours a day and i dont like to spend my mony on the battries.
i am using this radio when ever i sits on my computer and i have an another big radio but that doesn't catches that station as well as the small radio..
so can i use the power supply of USP port ??????????????????

 

[linuxking]

Yes, the USB is capable of provviding 5V, Pin 1 and 4 are the power pins

 

[Faisal__saf]

Thanx
actuly my radio is 3v volts only and i am afraid i will los tha nice radio if gave 5 volts instead of 3 volts,,..........

but i dont know that my fear is wright or wrong, cuold you help me please


thanx

Faisal,

 

[bogdanfirst]

you can use 3 diodes like 1n4001 in series with the radio and the power suply. the diodes have a voltage drop of about 0.6-0.7V on each. so putting 3 in series will have a voltage drop of 2.4-2.7V wich means that the radio will get 2.3-2.6 volts wich i think that it is great.
this is the simplest solution i can think of. you might use a zenner diode and a transistor.
you might use only 2 diodes.......

 

[linuxking]

When using the discretes ensure that the pin 2 and 3 are left alone (No Connection) adding any componets might let the PC (host) think that yer radio is another USB device, juz watch out.

You could also get a drop down regulator 5V to 3V from Linear Tech or Dallas/MAXIM

Linux

 

[Faisal__saf]

thanx you all

i will try your methods and i hope it will work..

and another answer also if i cn convert from 5 to 3 volt then i could also convert from 12 to 5 also for cd rom as an audio cd drive to use an adaptor as a powr

 

[Faisal__saf]

i tried but i dont know which wire is suply and witch are data
can you please explain :?

 

[Big4SMK]

the outer 2 are for power supply, the inner 2 are for data transfer

 

[linuxking]

Sometimes back there was an article in EDN titled "Stealing USB Port Power", see the PDF

Cheers
Linux

 

[Faisal__saf]

one more ..

Thankyou all of you..

I really felt very excited when I did my first experiment with computer

I Thout one thing more for that..
I can use the radio ar any device with USB's supply but the SPKs i have o connet sapratly or to the line iin of my sound card..
But is it possible to make the 2 data wires as the line in ore one of them.

I think it could be But i have to desing a circuit to change the audio analog signel to digital signal,, BUt how that i dont know.
and also we have to built a software for the controlin..and even this i dont know But may be there is a software for controlin like these equipments.. Do any knows any of these software located on the web..

I i could pass it will be like one of my dreams come true..

once again thank you all

Faisal....

 

[Faisal__saf]

Re: one more ..

:cry: :cry: I think no body wants to help me.... :cry: :cry:

 

[Mullemeck]

Most usb-ports can only supply about 500mA so make sure that your radio doesn't draw more than that or you might en up burning your motherboard.

another more safer way would be to take +5v from a molex connector inside the computer instead