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Pocket game system ripe for hacking? — Parallax Forums

Pocket game system ripe for hacking?

RaymanRayman Posts: 14,677
edited 2011-07-11 18:18 in Propeller 1
I've been looking for a long time for a game system to Propellerize...

This one looks pretty good. It's the NJ-250A at dealextreme.com for $17

I've dissected one already and it looks like a perfect candidate for main board replacement.
Haven't found the exact display datasheet yet, but I found one that is very close...

DealExtremePic.jpg


Here are some high-res photos of the insides:

100_6803.jpg
100_6800.jpg
100_6804.jpg
100_6801.jpg
100_6802.jpg
DealExtremePic.jpg
300 x 170 - 13K
100_6803.jpg
1024 x 768 - 158K
100_6804.jpg
1024 x 768 - 157K
100_6801.jpg
1024 x 768 - 99K
100_6802.jpg
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100_6800.jpg
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Comments

  • trodosstrodoss Posts: 577
    edited 2011-07-06 14:16
    That does look like a good system (...to rip apart and re-purpose)!
    I saw the NiMH batteries in one of the pictures and got excited...until I read the "not included" part :(

    The added A/V out would be fun to expirament with-- maybe you can generate composite on the Propeller and use the LCD at the same time? It is a thought.

    Looks like a great find.
    --trodoss
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-07-06 14:27
    In case anyone else whats to look it's here.

    http://www.dealextreme.com/p/nj-pocket-2-5-tft-lcd-portable-game-console-with-tv-out-and-built-in-games-3-x-aaa-65514

    It took a while to find it. My initial search returned: "Your search "NJ-250A" did not match any products".

    Ray, maybe you could salvage the AV connector. I see it has an "AV/OUT". Do you know what the resolution of the screen is?

    Duane
  • RaymanRayman Posts: 14,677
    edited 2011-07-06 15:19
    Yes, I think I would salvage the AV connector, if I did it myself...
    But, on the other hand, I'd probably want to sell just a replacement board.
    I think people could solder in a replacement board very easily, but removing the AV connector might be hard with just a soldering iron.
  • jazzedjazzed Posts: 11,803
    edited 2011-07-06 15:33
    Nice find Rayman. What all will you put on the board?
  • RaymanRayman Posts: 14,677
    edited 2011-07-06 15:51
    Good question...
    Probably just enough to make it play games.

    First though, I need to know if all the units have the same LCD.
    That's my biggest concern...

    Here are some good things about this particular unit:
    Main circuit board is in 3 parts, and I'd only have to replace the central section.
    Cost is low.
    LCD has a connector and so is more easily removed.
    Power switch and AV connectors are on bottom of board, so board thickness isn't an issue.

    Here are some bad things:
    My LCD has a bad pixel. Do they all?
    I can't find the exact LCD datasheet, meaning it'd take a bit of detective work to figure it out.
  • RaymanRayman Posts: 14,677
    edited 2011-07-06 15:58
    Actually, cost being low might be a bad thing...
    People might think twice about a $40 to $50 board to install in a $17 device...

    I guess what I should ahve said is that the simplicity of this device is good thing.

    I've also opened up other, more expensive, devices and Propellerizing them would be a lot more difficult...
  • David BetzDavid Betz Posts: 14,516
    edited 2011-07-06 16:29
    What processor does this thing come with?
  • jazzedjazzed Posts: 11,803
    edited 2011-07-06 16:32
    I like the dingo enclosure too.

    Displaytech has some high quality but cheap 2.4 and 2.8" LCDs now that might fit in one of these.

    I would include LCD, 2xQuadSPI, SDcard, FT232/USB and have footprints for accelerometer and RTC.

    I'm doing happy things with 2xQuadSPI flash these days. It's big, fast, and cheap.
    I'm running BASIC from it, and there are other language options coming.
  • RaymanRayman Posts: 14,677
    edited 2011-07-06 16:51
    David,
    Like most of these things, I think it comes with a SoC NES clone chip. I think it's the raw silicon with an epoxy covering.
    Can't tell for sure without destroying it due to the epoxy.
  • David BetzDavid Betz Posts: 14,516
    edited 2011-07-06 16:58
    Rayman wrote: »
    David,
    Like most of these things, I think it comes with a SoC NES clone chip. I think it's the raw silicon with an epoxy covering.
    Can't tell for sure without destroying it due to the epoxy.

    Not programmable then I guess. Your Prop replacement board will make it much more interesting! :-)
  • RaymanRayman Posts: 14,677
    edited 2011-07-06 17:01
    Well, I think it would be programmable in a way... I think there's a ROM chip there that I think has the games on it... You could maybe put your own games on it...
    I've read that a lot of these things use the original NES game data format...
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-07-06 19:36
    Nice find Ray.
    Do you have any inside pics?

    BTW, it doesn't matter that the prop board is more expensive than the device it is going into. The point is to find a cheap device that can be hacked :)

    Here is an AV4 connector that I am using (and selling, since I had to buy 1,000)
    http://forums.parallax.com/showthread.php?131734-Video-amp-Stereo-AV4-Connector-instead-of-RCA-(for-sale-too)&p=1001060#post1001060
  • RaymanRayman Posts: 14,677
    edited 2011-07-07 05:59
    Cluso, I would put in that connector, but the problem is that the device comes with a matching AV cable...
    So, unless I could find the cable for cheap, I'm not sure people would see the value.
    The device itself only has a single speaker. Do you have a good source for the cable?

    BTW: I do have pics. I'll try to find time to post them...
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-07-07 16:00
    I presume that the AV connector is not a standard 3.5mm then?
    For the AV4 connector I use the cables are from www.bqueenway.com (vii-win on eBay) $1.00 inc postage.
    see my post for more details http://forums.parallax.com/showthread.php?131734-Video-amp-Stereo-AV4-Connector-instead-of-RCA-(for-sale-too)
    I found other AV4 connectors with lower but wider profiles, and higher ones too. It depends on what fits. Otherwise, will a 1x4 pin header work - I have 4pin female housings and pin inserts if you require them (had to order 1,000 housings and 10K of pins) for my new projects.
  • RaymanRayman Posts: 14,677
    edited 2011-07-07 18:10
    Cluso, I think the connector is the smaller, 2.5 mm type.

    I've added some high-res photos of the innards to the top post so you can see what I'm looking at...

    BTW: Those buttons are resistive. You can see here how Parallax should have done their Quickstart buttons...
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-07-07 19:13
    Nice pics thanks Ray. I have not searched for the 2.5mm AV connectors, but they probably are available too.
    BTW the power switch looks like the horiz version of what I used on TriBlade. I bought them from DigiKey, and some horiz ones too. They are t/hole.
  • plainsteveplainsteve Posts: 33
    edited 2011-07-07 21:39
    Rayman said:
    BTW: Those buttons are resistive. You can see here how Parallax should have done their Quickstart buttons...

    What exactly do you mean by resistive? Is there not a carbonized rubber nub contact under each button to complete a circuit on press?
  • RaymanRayman Posts: 14,677
    edited 2011-07-08 03:09
    plainsteve wrote: »
    Rayman said:


    What exactly do you mean by resistive? Is there not a carbonized rubber nub contact under each button to complete a circuit on press?

    exactly... Pushing the buttons pushes conductive rubber down on the pads. Another way to do it is to push a dielectric onto the pads and look for a change in capacitance...
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-07-08 06:46
    Rayman wrote: »
    NJ-250A at dealextreme.com for $17
    Haven't found the exact display datasheet yet, but I found one that is very close...

    An idea of the resolution of the display?
    How many characters of 8x8 font text would fit, would it be readable?
  • RaymanRayman Posts: 14,677
    edited 2011-07-08 07:09
    I'm pretty sure the display is 320x240.
  • jazzedjazzed Posts: 11,803
    edited 2011-07-08 07:32
    Rayman wrote: »
    exactly... Pushing the buttons pushes conductive rubber down on the pads. Another way to do it is to push a dielectric onto the pads and look for a change in capacitance...
    At least you can reuse those parts. I've been wondering how to specify such pads on new boards.
  • David CarrierDavid Carrier Posts: 294
    edited 2011-07-08 12:00
    jazzed wrote: »
    At least you can reuse those parts. I've been wondering how to specify such pads on new boards.

    Look for PCB manufacturers that offer "conductive ink". They often don't have it in their online quoting systems, so you may have to contact the manufacturer directly to see if they offer it, what the design rules are, and how much it costs.

    I would have used it in the P8X32A QuickStart, but there really wasn't a way to get the buttons in the (relatively) small quantities that we would use them, and it would have been very difficult to hold them on to the board without a case.

    — David Carrier
    Parallax Inc.
  • RaymanRayman Posts: 14,677
    edited 2011-07-08 13:57
    David, I have to take back my earlier comment because it seems Beau just figured out a way to make the Quickstart buttons work nicely.

    But, regarding conductive ink on a PCB, I think you're talking about something much fancier that these buttons...

    There's basically a plastic part that pushes on a rubber part. The rubber part is like a cone with the base resting on the PCB. It is mostly non-conducting, but it has a center part that is conducting. When it gets squished, the conducting part hits the PCB.

    Here's a picture of some of the buttons and the rubber:
    Buttons.jpg
    Buttons.jpg
    1024 x 768 - 89K
  • David CarrierDavid Carrier Posts: 294
    edited 2011-07-11 10:39
    Rayman,
    I am familiar with that type of button. It does look like the button pads on the NJ-250A have straight ENIG without the carbon ink. Considering how cheap the system is, they probably did this as a cost-cutting measure. The rubber pad on the button can wear the gold plating off of the PCB contact. The conductive ink protects the PCB with minimal impact on the functionality, although in the short term it does work better with just ENIG.

    Mechanically, the touch pads on the QuickStart could work the same, but electrically they are very different; they don't have any pull-up or pull-down resistors. They are a bit more difficult to read, but when not used, they create almost no loading on the I/O pins, even when you are touching them. I also opted to forgo the carbon ink, because the QuickStart will likely not see the same abuse that a video game system would, and we had to keep the price at a minimum.

    — David Carrier
    Parallax inc.
  • WBA ConsultingWBA Consulting Posts: 2,934
    edited 2011-07-11 17:27
    In regards to small buttons for boards like the Quickstart and this game board, Peel-n-Place Snapdomes from Snaptron would be a good solution for a cheap button.
  • RaymanRayman Posts: 14,677
    edited 2011-07-11 18:18
    That does look like a good solution. I've seen them around, but they were soldered I think, not glued... They are dirt cheap either way though.

    I think the Quickstart buttons would work a lot better if they had the interleaved contacts like this thing does.
    This increases the sensitive area by about 5X or so.
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