prospective gcp build

[killersquirel11]

Hey all

Just looking at some stuff to build my own gcp. Probably work on it over winter break. Here's what I'm thinking of buying.

Haier 7" LCD Portable TV (has composite in, as a plus can take the over-the-air digital TV. Batteries supposedly last 2.5hr). Not sure on the specs on the batteries.

Gamecube and controller (of course...)

Using the specs from zenloc's post, I plan on building my own power supply (I have previous experience making power supplies.)

Depending on the batteries from the portable TV, I plan on either using those or buying my own.

Not sure on the case, probably just a couple sheets of acrylic for starters.

EDIT: found the replacement batteries on amazon: 7.4V 2200mAh. Not horrible, but still

EDIT: Some Math:
The built-in batteries:
7.4*2.2 = 16.28 W h

The gamecube, from the link above, doing some math:
1.9*6.6+3.3*.8+5.0*.3+12*.05 = 16.14 W power draw

The screen:
16.28 W h / 2.5h = 6.512 W

So a total of ~ 23 W of power draw
16.28 Wh / 23W = .7hr, so if you had a nominal power supply (100% efficiency), you would be able to get ~42-45 minutes. Since ~80% efficiency tends to be achievable, 33-36 minutes would be a reasonable amount to expect.

So I will probably be buying some better batteries. If I wanted >2hr, I would need almost 60 Wh of battery power, so 7800 mAh @ 7.4V or 5200 mAh @ 11.1V
(If you want help with the math, WattHours = (<desired time> / . * (16.14 + <screen_power_draw>) )
(Once you have WattHours, divide it by the battery voltage to determine the amount of mAh you need )

[The Smooth]

I'm going to predict that the batteries won't have much mah.

[bassmasta]

4:3/16:9 Switch widescreen + stereo speakers + battery for $53 shipped? Sounds like a great deal.
If you get that screen, please do take pictures of the insides.

[killersquirel11]

Some more info on the case that I've been thinking about:

Have the screen with the buttons on either side (typical case design, afaik) (might end up having all of the buttons on the back of the case, joysticks in front, so that you can hold it comfortably with thumbs in front, all fingers on back ready to hit all of the different buttons.)
From the front, the lines of the case would basically follow the screen on top and bottom, and on the sides round their way in
From the top/bottom, the case would be fairly skinny in the middle (screen area) and flare out into comfortable hand grips (big hands = big grips = more room for goodies in the hand-grips) on the side.
Depending on how much I can modify the disc drive, I plan on putting it inside one of the hand grips.
Batteries would either go behind the screen or in the other hand grip (or both).
Have a series of buttons on the bottom to keep the screen's original functionality.
Have all 4 controller ports on top (and a way to switch port 1 from being the built-in controller to being a plug-in one. same goes for A/V)


I'd draw a picture, but my paint-fu is feeling a bit weak right now...

Also, completely unrelated to my project, anybody know anything about that Wii Optical Drive Emulator (ik it probably can't be used for a GCp, but might be useful in a Wiip)

[killersquirel11]

Big bump with pics

I bought the screen, and my current plan is to leave the faceplate more or less intact (sorta a partial frankencase). Basically because I want to keep all of the functionality and don't really feel like mounting all of those tiny buttons.



The whole shebang (no controller atm)



and the way I am planning on setting this bugger up:

Notice how the disc drive has the motor and eye housing around the corner. The faceplate for the controller ports is going to need a couple 'minor' modifications

Finally, the part of the PCB that I'm interested in right now (namely the power connection)

My basic plan at this point is to have each one's wall supply power its own system, and have either a FET or a solenoid or something like that to make the gamecube draw power from the screen's battery line when on battery.

An album with the rest of the PCB etc is here:
GCP Album

[killersquirel11]

All right. A little bit more testing later and here's what I've found:

The battery is connected through a FET to the power supplies for the screen. The 12VIN goes through some circuitry which converts it down to charging voltages. When the battery runs out of charge, the circuitry built into the battery shuts it off. So, I plan to do the portable like so:


Basically get a switch that has 2 rails and 3 positions (so a total of 8 pins on the bottom), and have one rail control the input to the screen's battery port and the other rail control the input to the Gamecube's power supply. The plan is to have three modes:
1) Off (charging): GC PSU connected to nothing, Screen connected to wall wart
2) On (Battery): GC PSU Connected to battery, Screen NOT connected to wall wart
3) On (Charging): GC PSU connected to GC Wall Wart, Screen connected to wall wart

The main reason for this is that I don't want the gamecube to mess with the battery's charging circuitry. GND isn't shown since it's the same everywhere and would just clutter the drawing

Is this the right type of switch? It's a DP3T switch, which, if I am correct, is what I want
http://search.digikey.com/scripts/DkSea ... e=SW334-ND

[killersquirel11]

The power supply, since the GC PSU apparently can't be run off of 7.4v (or at least that's what I've read from other threads), will be a custom one based off of the numbers in this thread

$9.5 .59~5.1 output voltage 10A output
http://search.digikey.com/scripts/DkSea ... 07-1384-ND

$4.52 5V 1.5A
http://search.digikey.com/scripts/DkSea ... -2196-5-ND

$4.52 3.3V 1.5A
http://search.digikey.com/scripts/DkSea ... -2195-5-ND

and then just run the 12V part off of the PSU VIN, which will either be 7.4 or 12V

Plus that switch from above to bring the order to around $20 +S&H

[Ashen]

nice find on those regulators, much cheaper than the ones suggested. I will have to check them out.

[killersquirel11]

nice find on those regulators, much cheaper than the ones suggested. I will have to check them out.

Yeah I do a lot of work on the robot team here at my college. Our team-designed centralized power supplies have had a very high failure rate, so I was searching for replacement options and came across these. They should be cheap enough to put one on each of our boards and not have to worry about a centralized power supply system (thus making less cable clutter, and allowing each board to be tested/debugged individually).

According to the datasheet,
Rtrim = 1.182 / (Vo - 0.591) kOhm
so when Vo is 1.9, Rtrim is 903 Ohms.
The closest digikey has are 900 and 909, and the 909 is cheaper (and I'd rather undervolt slightly than overvolt slightly)
So (1.182/Rtrim)+.591= 1.89133V, which should be plenty close
I'm also going through hole for this one since it has to go between pins 3 and 5

There also needs to be a 30.1k pull-up resistor between pins 1 and 2, so I'm going with this 0805 Surface-Mount resistor

[killersquirel11]

It's been a while since my last update, I've been a bit busy lately. Anyways I decided that I didn't want to risk the prying method of removing connectors, so I tried the 'use a lot of solder and soldering irons to heat up all of the pins at once and then remove the connector' method.
This is what I'm not doing:

This unfortunate decision caused a couple of gobs of molten solder to fall off of the bottom of the board, one of which landed on my thumb and one of which landed on a bag of oreos . As a more-or-less knee-jerk reaction, I shook my hand to get the solder off, causing the soldering iron that that hand had been holding to fly to the ground and land approximately 2 inches away from my lipo batteries. After unplugging the soldering irons, placing them in a safe place, then running my thumb under ice-cold water, I decided to take a more brute force approach: Destroy the connectors and then pull the pins.

I'll take some more pictures once I get back to my apartment, but basically take whatever tools you have at hand and crunch the connectors. I used a combination of side cutters (aka wire cutters) and needle-nosed pliers. Here's the process:
1) Using the side cutters, squeeze as hard as possible on the edges of the connector
2) Using the needle-nosed pliers, peel away the metal shielding
3) Using the side cutters, hack away at the soft plastic innards
4) Using fingers or needle-nosed pliers, remove the plastic bits
5) Using a soldering iron and needle-nosed pliers, remove the pins one at a time.

[bassmasta]

You could just desolder the pins, with solder braid or a desoldering iron. Then you could save the ports.

[Ashen]

De-soldering all those pins is a real pain in the ass. Just take a pair of pliers and twist right in the center of those connectors, they come right off. Of course you have to be careful not to scratch the board this way. I don't really worry about it though because 50% of the board can be removed anyway.