The Raindrop

Lord Steve

For a couple years I wanted to make my own video game console.· Everybody's doing the TV/VGA console thing; I wanted to do something different.· The Propeller inspired me to make a handheld.· So, I present the Raindrop:· a GameBoy-like handheld console (in prototype stage, see below).

• 128x128 OLED (SparkFun), with parallel data bus (8-bit)
• Stereo audio via headphone jack (audio DAC uses a circuit very similar to the Propeller Demo Board)
• 12 input buttons, connected to the Propeller via two 74HC165 parallel-to-serial shift registers
• microSD card connector
• 64K serial EEPROM (Mike Green always wants to see 64KB, hi Mike!· [noparse]:D[/noparse] )
• 6.25 MHz oscillator (allows for 100MHz with 16x PLL)
• Serial over USB (FTDI) in the standard Propeller configuration (thanks to Phil Pilgrim for the 74LVC2G07 circuit)
• Two general-purpose LEDs
• 3.3V step-up regulator for system power
• 12V step-up regulator for OLED display power
• Powered by AA batteries in plastic AA holder with switch·(the idea was to attach it to the back of the PCB with double-sided tape)
• And of course, the Propeller (TQFP)

Sadly, I somehow ruined·the two OLED displays I was using for prototype testing and SparkFun is out of stock of this item, with no ETA on new supply due to manufacturer issues.· So, after doing a little searching on the 'net for a similar replacement, I have decided to stop work on this project and get going on something else.

What I have shown a photo of is the 2nd prototype (with a nonworking screen so no graphics, sorry).· AdvancedCircuits fabbed the PCB.· I was hoping the third and final incarnation would be a 4-layer PCB replacement for the original PCB of a Super Nintendo Controller.· Cut away some of the front and back of the plastic SNES controller housing and you got a nice case for your Raindrop.· Oh well...

I have attached the schematic and the objects I used to prototype (which serve as a kind of standard library).· I used some of the objects from the OBEX and have included them in the ZIP for completeness' sake.· Credit goes to the respective authors.

Thanks to those who answered my forum questions in particular and to those who add to the knowledge base here in general.· It's a direct consequence of such knowledge sharing that someone like me could piece something like this together.· And that's really all it is, piecing together small subsystems to make the whole.



Post Edited (Lord Steve) : 4/4/2010 6:46:54 PM GMT

logan996

This is amazing! This looks so professsional! would you sell this even without its screen? if so how much? if you arn't willing to sell it then could you keep developing it? wpuld it be possible to have a bigger screen?

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"When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

· Thomas Jefferson
·

Lord Steve

@logan

Thanks for your kind words.· The problem with selling these prototypes with no screen is in testing the boards after assembly.· I never really thought to sell the prototypes.· The solder joints of the buttons on the bottom side of the board are pokey so it's not a product that could be played a lot.· That reason, and the fact that having a custom case made seemed too daunting,·are why I wanted to mod a Super Nintendo controller with a custom PCB designed to replace the PCB in a SNES controller.· A different screen could be used, sure.· I had no success finding one that I liked at a similar size which provided parallel access to the OLED controller.· (That's critical for good frame rates.)· Also, the audio on even the second prototype leaves a little to be desired.· It kind of hisses and "warbles" when music isn't playing.· I thought I would replace the DAC circuit (copied from the Propeller Demo Board) with an actual DAC IC on the final version.

Mikerocontroller

This is a neat looking·board.· I hope you get the OLED issues sorted.· The OLED's are so brilliant and really add to the WOW factor.· I too have a pair of dead OLED's and really miss working with them.· I really wish I knew what I'm doing to kill them.· My latest OLED outputs a very faint display.· Good luck with this project!

JD

Steve,

Are you aware that Parallax has a similar display? Perhaps this could help the project along; here is a link for your review.

µOLED 128:
http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/uOLED/List/0/SortField/4/ProductID/452/Default.aspx



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Respectfully,


Joshua Donelson
www.parallax.com

Lord Steve

@Joshua

I knew about that Parallax OLED, but it is communicated with serially while the one I was using had a parallel data bus.· The throughput of the serial devices is too low for high-frame-rate games.· Thanks for your suggestion! [noparse]:D[/noparse]

JD

@Steve,

Agreed, the serial version has limitations regards to refresh rate; I just wanted to make sure that you knew of our module as perhaps it would continue the project. It’s always a shame to see projects put on the back burner because of availability of parts.

The best of luck to you,

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Respectfully,


Joshua Donelson
www.parallax.com

Phil Pilgrim (PhiPi)

Have you tried these guys?

stores.ebay.com/Ego-China-Electronics

They seem to have a lot of available choices.

-Phil

Lord Steve

I had not seen Ego China.· They didn't have any OLEDs near 128x128, which is a great size for this project because a frame buffer of byte-sized pixels can fit in RAM·(if one were inclined to use a frame buffer approach) and 128x128 is also big enough for games.· 128x64, while being more memory-friendly, makes general gaming more difficult.· Thanks for the link, though, I like some of their OLEDs.