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How to Make a Portable Game System

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Step 19: If Your Batteries are More Than 9v

Picture of If Your Batteries are More Than 9v
What you need:
Soldering Iron
7805 Regulator
470ohm Resistor
220ohm Resistor

Don't hook up the screen just yet - we need to build a small regulator for the screen.

It's very simple, just follow the diagram below.

You can use a 7805 to get 8v, or you can use a 7808. A 7808 is just like a 7805, but it gives out 8v instead. Using a 7805 is much more convenient in my opinion, because you can easily find them in old electronics. If you want to know how this works, then check the last paragraph.

The PS1 screen can handle from 6.89v to 8.5v. Preferably, it should get 7.5v, but as long as you have a decent 7805, you'll get the voltage you need. As always, test the output voltage before hooking it up!

BUILDING THE REGULATOR
To build the regulator, just solder the 220ohm resistor to the ground (middle) pin of the regulator. That will be your ground, which you must connect to the screen's ground, too.

Solder the 470ohm resistor to the ground pin of the regulator BEFORE the other resistor. Solder the other end to the output pin, and that is your 8v out, which you will connect to the blue wire of the screen in the next step.

Just like the NES's regulator, it's a good idea to put a small heatsink on this one, too.

Solder the negative lead of your batteries to the ground spot on the regulator. In a couple steps, you will solder the 8v out connection to your screen. For now, just leave the V+ input and 8v out wires disconnected.

HOW IT WORKS
This works because it is essentially a LM317T regulator, but with a higher output voltage. The LM317T is an adjustable voltage regulator. It can output anything from 1.5 to 12v with a 15v input source. All you need is two resistors. You hook them up in the same way as below, except you would choose different resistor values for different voltages. So why does the 7805 work for this purpose? Because the LM317T is simply a fixed 1.25v regulator. Experimenters rarely use anything below 5v, so a 7805 can do the job as well.
 
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freedom252 years ago
hi there sir, i'm just wondering how can i use my AN7805, the output voltage is 5volts when supply it with a 9volt battery wit attaching some desired capacitors on it, but i need 4.5volts for the supply for my PIC program kit, i need circuit diagram sir.. i'm new for this situation but because of school project i am pressure to build this regulator. . .hoping for your response... ^_^ thank you.
MastrGmr3 years ago
If my batteries are exactly 9v, would I need a regulator?
1up (author)  MastrGmr3 years ago
I can almost guarantee you they will be over 9v when charged, and if not, that's still pushing it. Yes, you should use a regulator.
duck51483 years ago
i am making a game cube portable powered by a 12.8v LiFePO4, could i use this regulator to power the psone screen.
1up (author)  duck51483 years ago
Sure, but it will be dissipating a lot of heat (because the voltage it being dropped by almost 4.5v). I would look into a switching regulator. They generate very little heat and save a lot of current.
bnapier964 years ago
do you think 8 volts will fry a 7.5 volt screen. I'm using 8 1.2 AAA recargable battiers
1up (author)  bnapier964 years ago
Depends on what screen. If it's the PSone screen, it will be fine, it can take up to 8.5v. As a general rule, most electronics can usually take .7v or so more than they say they can, but there are exceptions. What screen are you using?

Bottom line, it'll probably be fine, but there's a chance it won't.
bnapier96 1up4 years ago
it is a screen from one of those car seat dvd players. on it it says a +7.5 v. in,plus do ineed a volume amp. cause i only want a mute and non mute switch. and one more thing to charge NiMH battiers can i just a 9 volt charger from the Original NES or will it overcharge them.
1up (author)  bnapier964 years ago
I'm quite sure it will be fine with 8.1v. You only need a volume amp if the screen doesn't have one. And only charge batteries with the charger they're supposed to be charged with, ever.
MrExcellent4 years ago
So, if I understand very well:
INPUT it's from the battery
GROUND to the screen
OUT to the NES

Is it right?
1up (author)  MrExcellent4 years ago
No, INPUT from battery, GROUND to ground, and OUTPUT to the + input of the screen.
Jaapio5 years ago
I have about the same question as Reeper, I have a ps2 the adapter says 8.5 vols 5.6A and ps psone screen. And I have a ps2 that runs off of 12 volt(amp unknown for now). I want to do a vehicle setup too. What would you recommend me to do?
1up (author)  Jaapio5 years ago
The PS2 slim needs 8.5v and no more, so you'll need to make a regulator. Two 7805's can do the trick, wired up like this:
http://i37.tinypic.com/e89xt4.jpg

The PSone screen needs 7.5v, just follow the diagram in step 17 of this Instructable.

PS2 a/v pinout:
http://www.gamesx.com/avpinouts/psxav.htm

Hopefully that'll be all the info you need.
hey, would the 7808 voltage regulator deal well with a input voltage of 14.4 as i want to create portable snes with a long battery life ( using a li-ion 14.4 volt 6400mah)
1up (author)  Andy_RussianAK4 years ago
It'd be fine, but waste a lot of energy. Linear regulators use up the extra power as heat. Try getting a switching regulator for the screen and SNES, that'll guarantee TONs of battery life. If you need help, just ask.
Jaapio 1up5 years ago
I have a question, what input voltage are you expecting? I folloed the diagram with the two 7805s and I ended up with 5 volts. The one with 1 regulator delivers 8.
Jaapio 1up5 years ago
Hi, so I'll just use a ps2 slimeline instead of a the old model. Thanks.
saidthety5 years ago
I was curious if anyone had any experience with the Super Joy (Nintendo on a Chip) controllers. I have one (It's apparently not working for some reason...) that I'd like to mod into a portable console. Anyway, I was wondering if I could run the screen and everything with the 4 "AA" batteries that the Super Joy can run off of. Anybody know?
Here is a link to a youtube video. The portabilizer uses a voltage booster so a super joy can run on 4 AAs
http://www.youtube.com/watch?v=UNOwNN_13kY
I hope this will help. The chip is from Texas Instruments as a free sample.
Ah, thanks for the link.
Reeper5 years ago
So, the lm7805 will output voltages other then just 5Volts when the resistors are added? Good to know. I am going to try to do this with a n64 except it will be an in vehicle setup so my input is going to be 12 volts. The n64 takes in 12v at .8 A AND 3.3V at 2.7A, could you suggest a method of getting the input power converted properly from a 12 volt cigarette plug in a car? that would be nifty, I love the building but I haven't much knowledge of all these components.
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