joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

RetroPie Player inside a GBA SP Shell!

Wed Jun 08, 2016 3:35 am

Could someone please check my parts list to see if I forgot anything?

[CORE]
- RPi0 (not sure if the version with camera or not, does it matter?)
- LCD
- GBA SP shell + buttons
- Battery
- DC-DC booster to convert battery up to 5V *note: Not the recommended alternative to 1000c; seems to serve the same function for less
- Audio Amp
- Speaker

[MISC]
- Copper Tape
- Electrical Tape
- Exacto Knife Kit
- Soldering Iron
- Solder
- Hot Glue Gun & Sticks
- OTG USB Cable

[PARTS I ALREADY HAVE]
- Micro USB B to USB A cable (for power)
- Mini HDMI to Full HDMI Adapter
- HDMI Monitor
- USB Keyboard
- Spare Ethernet Cord (a sacrifice to the 26 AWG wiring gods)
- Small Tri-Wing & Phillips Screwdrivers
- Random cords w/ (hopefully) 18 to 22 AWG for powered wiring (SATA cable? One of the extra OTG cables I linked earlier maybe?)

[THINGS I MIGHT STILL NEED OR ARE UNSURE ABOUT]
- Audio Buffer Board | I'd prefer to connect amp/speaker directly to the RPi0 & avoid this part if possible.
- Low-pass Audio Filter | I don't need this if it's only a sound quality thing, lol did you see the speaker I'm using?
- Potentiometer | I'd prefer a fixed volume & avoid this if possible.
- Switches | Unsure on exact sizes/quantity. Pi GRRL Zero guide recommends 8x 6mm, 2x 12mm & slide switch for power IIRC.
- USB Hub | Guide recommends this but I don't see a reason for it if I don't require more than 1 USB device at a time.
- Micro USB Port | Unsure what this is for. RPi0 comes w/ 1 for Data & 1 for Power already. Plus there are 2 points on the underside that can be used instead of the actual port {I think it is still the same port though so it's not like you get an extra USB by using these points})

joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Wed Jun 08, 2016 7:45 pm

Update: That cellphone battery is too big, so looking for alternatives. Must be 2000 mAh or better, would be awesome if it was 5V so I could drop the booster from my design. Also on the audio stuff, I think I'll be building a PWM circuit so I guess I need to order a 270R, 150R, 33N & 10U for that.

joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Thu Jun 09, 2016 5:15 pm

Speaker turned out to be 1.5W. That is going to be quite a bit louder than the 0.5W that most people used. Will be interesting to see how it works out.

I still need to order switches and a battery. The goal here is to be as simple and cheap as possible while still retaining that stock look. I'd love to see some 5v battery options if anyone knows of any. There are downsides to having to use a DC-DC booster.

joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 2:55 am

nobody?

drgeoff
Posts: 10109
Joined: Wed Jan 25, 2012 6:39 pm

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 9:56 am

There is no such thing as a 5 volt cell. You always need a DC-DC converter to step up or step down and to give a constant 5 volts to the RPi as the cell voltage falls.

If you use a USB powerbank the booster is already inside that. And the charging circuit is in there too. If using a lithium cell, you MUST use a proper charging circuit. Otherwise you risk the cell exploding or burning fiercely, with attendant risk to life, limb and property.

joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 10:02 am

drgeoff wrote:There is no such thing as a 5 volt cell. You always need a DC-DC converter to step up or step down and to give a constant 5 volts to the RPi as the cell voltage falls.

If you use a USB powerbank the booster is already inside that. And the charging circuit is in there too. If using a lithium cell, you MUST use a proper charging circuit. Otherwise you risk the cell exploding or burning fiercely, with attendant risk to life, limb and property.
Hmm I did not realize that powerbanks have boosters in them, but now it makes sense.

About the non-existence of a 5volt cell I still don't get that. It would be extremely useful these days with all the devices designed to run off 5v. There's 6v 9v 12v 24v and on and on, so I don't see a real reason other than manufacturers just haven't realized there is a market out there for them yet.

You mention voltage falling...my cellphone runs off a battery that gives 4.4v on a full charge and then falls to 3.7v. Following that same progression I would recommend designing a cell that gives 5.2v at full charge and falls to 4.8v.

jamesh
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Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 10:41 am

It's to do with the chemistry used to produce the voltage. There is no 5v chemistry that I know of. So you need to use what you have, then convert to 5v.
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joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 10:45 am

jamesh wrote:It's to do with the chemistry used to produce the voltage. There is no 5v chemistry that I know of. So you need to use what you have, then convert to 5v.
I had no idea that it is so complicated lol. I guess I figured if you can create a battery out of a lemon then the acidity or size could be adjusted to whatever voltage is desired.

So what about putting 2x 2.5v batteries or 5x 1v batteries into a pack? I forgot which is what but I know you can do a series or parallel. One way would give 2x or 5x the volts, and one way would give 2x or 5x the capacity.

Tekkaman_Slade
Posts: 2
Joined: Wed Jun 08, 2016 9:29 am

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 11:44 am

@joe7dust - If this is your first build of this kind, I highly recommend you read through the build instructions and learning tutorials for the PiGRRL 2 and Pocket PiGRLL at Adafruit. That should give you a good understand of the technology and components required for such a build.

https://learn.adafruit.com/pigrrl-2/overview
https://learn.adafruit.com/pocket-pigrrl/overview

There is a lot to consider before you select specific components let alone how you'll put everything together and that's just the hardware side of things. Things can get just as complicated if not more on the software side depending on the build. This kind of build is really not for beginners, but is a fantastic way to learn.

Take a look at what's possible.

https://retropie.org.uk/forum/topic/960/neopigamer

joe7dust
Posts: 29
Joined: Mon Jun 06, 2016 7:52 am

Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 11:51 am

Tekkaman_Slade wrote:@joe7dust - If this is your first build of this kind, I highly recommend you read through the build instructions and learning tutorials for the PiGRRL 2 and Pocket PiGRLL at Adafruit. That should give you a good understand of the technology and components required for such a build.

https://learn.adafruit.com/pigrrl-2/overview
https://learn.adafruit.com/pocket-pigrrl/overview

There is a lot to consider before you select specific components let alone how you'll put everything together and that's just the hardware side of things. Things can get just as complicated if not more on the software side depending on the build. This kind of build is really not for beginners, but is a fantastic way to learn.

Take a look at what's possible.

https://retropie.org.uk/forum/topic/960/neopigamer
Yes I have seen those threads before. I'm just waiting on my display to come in from Singapore, and in the meantime now I need to select the right battery and order the proper switches. I have heard it would be much easier to use the switches from an original GBA SP motherboard than to insert my own switches (like the ones in the pi grrl guide) under the buttons I got with that shell I linked in the OP.

If you have any specific tips, especially in regards to getting my hands on a battery that outputs 5v natively or assembling a pack of batteries in series or parallel to accomplish the same thing -- then I would be very interested.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24667
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Re: RetroPie Player inside a GBA SP Shell!

Fri Jun 10, 2016 1:09 pm

joe7dust wrote:
jamesh wrote:It's to do with the chemistry used to produce the voltage. There is no 5v chemistry that I know of. So you need to use what you have, then convert to 5v.
I had no idea that it is so complicated lol. I guess I figured if you can create a battery out of a lemon then the acidity or size could be adjusted to whatever voltage is desired.

So what about putting 2x 2.5v batteries or 5x 1v batteries into a pack? I forgot which is what but I know you can do a series or parallel. One way would give 2x or 5x the volts, and one way would give 2x or 5x the capacity.
Here are some example battery chemistries:

NiCd 1.2v
Lead Acid 2.2.v
NiMH 1.2v
Lithium ion 3.6v

You can put batteries of same type in series to add voltages, so two lead acid would be 4.4. But note, nothing adds up to 5! You can get 4.8 using NiCD or NiMH, but that's too low.

https://en.wikipedia.org/wiki/Battery_(electricity)
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
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