Quick Dirty Usb Charger


DusteD

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Okay, first of all, sorry if this is the wrong section.

Here is a very cheap, fast and easy way to make a charger that will work with most USB powered devices (wiz, ipods and other mp3 players that charge via usb, stupid little led light and all that stuff), and it can be powered from almost any available power converter and even from the power in your cigar-igniter in your car.


Tools (stuff everybody should have laying around):
Metal Drill (size is less important, between 3-5 mm in diameter)
Soldering iron (or storm ligther), both optional, but be pro, solder your stuff ;)
Screwdriver for your screw

Materials:
Thermal paste (any quality, optional but recommended)
Solder tin (optional, but really, soldering is for winners)
Glue (I used hotglue) (or tape if you're cheap)
Screw+Bolt that goes together and is about 3 mm dia, length don't matter, just "long enough"
Heatsink (any will do, a heatsink from a old graphics card or old cpu (like those on 486's or pentiums, they are great)
TS7805 - Voltage regulator with 5 volt regulated output, pretty common component, take some old hardware apart and you might find one there.. dumpster diving for the win ;)
USB socket (female), any will do, the one I used was salvaged from one of those horrible iMac keyboards (they have the "user friendly" correct this time, notice on my pic how the RED wire is + and BLACK is GND, cool, huh)
Standard lowpower socket (femal), those found on almost anything that uses electricity from a transformer (again, dumpster diving)

Here's the deal, the TS7805 is a great little voltage regulator that will take anything from 10 to 30 volts and turn it into a really stable 5 Volts that is what all USB devices use,
but when it does that, it generates A LOT of heat, and to keep it from burning out, we put it on a heatsink, the one used in my picture can charge a Zen Stone from 30 volts supply
but then it becomes so hot that the hot glue melts.. and burns you ;)

So, drill a hole through the heatsink, big enough for your screw to come through it,
put on the 7805 on the heatsink and secure it with the screw, to ensure a good thermal contact.
Put the power and usb plugs on there too, use some glue or tape to put secure them to the heatsink.

The pinout on the 7805 (when the block is facing you) is:
0 - Vin (voltage input, anything from 10 to 30 volts)
1 - GND (shared ground)
2 - Vout (voltage output, a stable 5 volt)

The usb female pinout (when the back of the plug face you)
0 - GND
1 - +data
2 - -data
3 - +5Volt

So we connect it like this:
Powerplug + -> 7805 Vin
Powerplug - -> 7805 GND
And
USB GND -> 7805 GND
USB +5V -> 7805 Vout

Here's a pic of mine, I've used it with many diffrent devices and with voltages from 9 to 30, on 9 it's not able to deliver a whole lot of amps, so you might need to use higher voltage to charge a wiz.
fix.jpg


Now all that's left is to plug in the usb cable, and give it some power, either from a transformer in the valid voltage-range, or from your cars ciggy-ligther (that's 12 volts, it's fine)

Ofcause you need a transormer with a plug that fits the one you chose for this one, but if you don't care about plugs, skip the power-in plug and just wire it directly to a transformer.

I suggest you test it using something less expensive than a wiz.. maybe a multimeter/voltmeter to check that you got it right and didn't flip the +/- on the USB (I don't think the wiz likes -5 volt)
 
Audi said:
sounds like a lot of effort

Yes, it's crazy, it took almost a whole 4 minutes, I'd rather go buy a way more expensive wallcharger, because that's how expensive my time is :p
 
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DusteD said:
Audi said:
sounds like a lot of effort

Yes, it's crazy, it took almost a whole 4 minutes, I'd rather go buy a way more expensive wallcharger, because that's how expensive my time is :p

I'd say a lot of us wouldn't have this done in 4 minutes by any means. Plus, wall chargers can be pretty cheap if you shop around!

Still, this is a good tutorial, just don't be so surprised that it won't be worth it for some people.
 
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DurTahar said:
I'd say a lot of us wouldn't have this done in 4 minutes by any means. Plus, wall chargers can be pretty cheap if you shop around!

Still, this is a good tutorial, just don't be so surprised that it won't be worth it for some people.
Thanks :)
Yee, I know, some have a hard time with stuff like this, but seriously though, if you have a hammer for taking apart the USB keyboard, then 4 mins is not unrealistic :p
 
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A 7805 on its own is going to sing like crazy - at least add an 100nF cap to the output to smooth it out a bit. Wouldn't hurt putting one on the input too.

If you want to do it properly, you would typically go for a switch mode power supply instead, but as a "quick and dirty" the above is fine. Just add some caps.
 
Squidge said:
A 7805 on its own is going to sing like crazy - at least add an 100nF cap to the output to smooth it out a bit. Wouldn't hurt putting one on the input too.

If you want to do it properly, you would typically go for a switch mode power supply instead, but as a "quick and dirty" the above is fine. Just add some caps.

Yes, caps on input and output is always a good idea :)
There's no rectification done in this, so you'd need a dc psu for it,
shouldn't matter if it's switchmode with such a small device, but you could always add 10mF too, to smooth it a bit more.
 
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A small device like the Wiz can still make that 7805 leave burn marks in your fingers, hence the reason why I suggest SM to power it instead. I always use SM for anything > 250mA as linear regs such as 7805 are just too inefficient.
 
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