Electronics questions...

CZroe

Lifer
Jun 24, 2001
24,195
856
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Controller Pinout

First of all, how do I measure how much amperage the GCN controller outputs on the 5v line? How do I measure how many amps my 3.3v device will require? Will the total amperage output be less once I do the conversion to 3.3v?

Where can I find a schematic or guide for building something like a 5v-to-3.3v stepdown converter? The parts require nothing more than a trip to Radio Shack, right?

How can I tell if a power draw on the first controller port will affect the fourth? Are they the same "rail?" If I connect four of these devices, I'd want to make sure the GC could power them.

I'm not expecting a schematic and list of parts to pop out of this request, but I do need a little hand-holding here :)

Thnx!
 

Lynx516

Senior member
Apr 20, 2003
272
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not sure about your first question as it does not output on the 5V powerline but inputs. To measure the current your 3.3V decive needs you need to either build it if it has active components or measure its resistance if it is passive. Not sure on the third question a bit more explination might be needed. In what way do you need to steop down from 5V to 3.3? if it is a constant voltage then a voltage regulator will do nicly if not then I need more details. On the last question you cannot tell easily straight off the bat. It depends on the internal regulation e.t.c of the system.
 

Vapor10k

Junior Member
Apr 26, 2003
10
0
0
This is what your gona need to do if you want to step that 5v down to 3.3v. First off your gona need a Ohm meter or multi-meter. To find the amount of current on your GCN controller outputs you need to measure the Ohms or resistance of them. Then your gona take the voltage which in this case is 5v and divide that by the resistance or Ohms, thus giving you the current which im believeing is gona be in the mA's. Then you need to go down to radioshack and find a resistor that will cut the voltage to the amount needed. Solder that thing in series with the GNC creating a voltage divider.

Good Luck
 

Burner

Member
Oct 25, 1999
85
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vapor's method may work if the current is constant but usually isn't a very good solution.
You can probably find a voltage regulator that will take in 5v and output 3.3v, searching at digikey found several that you would want. I'm sure radioshack would have something that will work as well
 

IamElectro

Golden Member
Jul 15, 2003
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Originally posted by: Burner
vapor's method may work if the current is constant but usually isn't a very good solution.
You can probably find a voltage regulator that will take in 5v and output 3.3v, searching at digikey found several that you would want. I'm sure radioshack would have something that will work as well


I would concur with this approach as it will be the most stable. Rat Shack does sell a Voltage regulator that you can set its specific output with a resistor as to obtain the 3.3v. I would recommend a 1% or better tolerance resistor though. Anything over this may cause some unwanted fluctuations in the voltages.

It may help if we knew what the application for the controller was for.
 

syberscott

Senior member
Feb 20, 2003
372
0
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No need for a voltage regulator here.
If the current is less than 20mA just slap a normal LED in series and you'll get your 1.7V drop to 3.3V.
Or you could use 2 silicon diodes for 3.7 volts, or 2 silicon and 1 germanium for 3.4 volts.

It looks as though pin 6 is alreadt 3.43 volts though, so why not use that?
 

CZroe

Lifer
Jun 24, 2001
24,195
856
126
Originally posted by: syberscott
It looks as though pin 6 is alreadt 3.43 volts though, so why not use that?

Can I? It's labeled as a logic pin. The device will operate alongside another controller device, so I wish to minimize any interferance. The controller will not require +5v for the rumble function.
 

Mark R

Diamond Member
Oct 9, 1999
8,513
14
81
If you want the easy way out, and don't mind a more expensive solution then use a 3.3V LDO regulator. This will provide a stable 3.3V supply from the 5V line.

All you need is the regulator chip (about $.30) and a capacitor (about $.30). A couple of diodes will work, probably well enough. However, a regulator is the optimal way to do it.

Any good electronics supplier will have dozens of suitable regulators to choose from.
 

CZroe

Lifer
Jun 24, 2001
24,195
856
126
I wouldn't have the slightest idea how to make a schematic for something like that :)

How would I choose what diodes to use or how many? All I know about diodes is that they only allow electricity through one way (And that geranium diodes are used in crystal radio projects ;)). I guess I need some basic electronics classes.

Anyone know of a good free resource I can read up on it through?

As far as the device being worked on, The cat's out of the bag.