My Homemade Bob


nubie

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GameGod posted on Mar 2 2007 at 03:24 PM said:
Jackd: It's hard to tell from the pictures, but it is a USB female plug on there... (You do need to plug a USB hub into that though, so you can use non-3.3V USB devices with it.)

As for a HOWTO, I don't really know what to say. I just looked at the pinouts for everything and just wired it up. I can give you all the resources I used though, and my parts list:

EXT connector pinout: http://wiki.gp2x.org/wiki/Image:Bob_ext.png
(The USB host part and the TV/Audio out part is all that I used.)

USB filter: http://wiki.gp2x.org/wiki/Image:Bob_usb_filter.png
That picture illustrates how to wire up the filter circuit for the USB host port. For some reason or another, the GP2X's USB signal is quite crappy, and this circuit smooths it out.

S-Video pinout: http://www.ghearing.com/?Gabe:ATI_All-In-W...t:SVideo_Pinout
All you should be concerned with here is the 4-pin version. The luma and chroma should be hooked up to the EXT port's VIDEO_Y and VIDEO_C pins.

Parts:
- S-Video female jack (4-pin)
- Two RCA female jacks
- Two 50 pf capacitors (the filter circuit asks for 47pf, but 50pf worked fine)
- Two 33 ohm resistors
- Two 33 kilo-ohm resistors
- Samsung E810 USB cable (inside the E810 USB cable's EXT connector is a relatively easy configuration of the 24 pins for soldering. You'd think 24 pins in such a tight spot would make it ridiculously hard to solder, but the way they're spread out is quite clever, and it makes your life a lot easier. I don't think the E810 serial cable is like this, so I'd definitely recommend getting the USB one.)

I just want to point out that there's nothing new in the information that I posted above. All I did was scrape information from the wiki to construct my BOB... all the hard work in figuring out the details was done by other people before me. :)

Everyone seems to have ignored my how-to :wacko: , but thanks for making a great BoB, that is how to do it, and I never thought of binding the USB jack to the board like that, it could definitely work. Will that fit in a project box? If so then we can have a BoB in a case for less money than the commercial one (maybe even put a stand on top, a 1.8" HDD and batteries inside ;) ).

I have even higher-res photos of my BoB, and I have borrowed a camera from a friend so I expect to get some nice shots of the super-mini USB termination circuit, next to my machinist's ruler it will indeed give you some sense of scale.

Now that you can see what is involved, many of you may realize that USB can be added to the current TV-Out cable for under $1 in quantity (several hundred), and demand should be high. It is literally just 4 extra wires; a very simple, very tiny circuit; and a USB jack. Now that I am getting another GP2X (been without for ~6 months or so) maybe I can cobble up a USB project board using the micro chip.
 
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nubie

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GameGod posted on Mar 1 2007 at 05:09 PM said:
It's not my best soldering job ever, but it works, lol... It's got a USB host port (with the USB filter circuit found on the wiki), S-Video out, and audio out. I used a Samsung E810 USB cable to get the 24-pin connector.
I forgot to add earlier. Why did you solder the board upside down? Usually the through-hole components go through a hole and then get soldered, it would have made the whole thing a lot more stable and easier too.

I see your way sort of works, but if you flipped the board over you wouldn't have needed any hot glue and everything would be anchored to the board when you finished.
 
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GameGod

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hahah, nubie, I'm surprised nobody else has pointed that out yet. :p

It's upside down because my dad drilled the holes for the SVIDEO and RCA plugs the wrong way, and I didn't feel like redrilling them myself (or making him redo it.)

If I ever build another one, I'll do it the right way. :)
 

nubie

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GameGod posted on Mar 4 2007 at 10:34 PM said:
hahah, nubie, I'm surprised nobody else has pointed that out yet. :p

It's upside down because my dad drilled the holes for the SVIDEO and RCA plugs the wrong way, and I didn't feel like redrilling them myself (or making him redo it.)

If I ever build another one, I'll do it the right way. :)
I can see that now, I didn't realize you had to drill in holes at first.

I want to make a USB/TV cable that is so small it looks at first to just be a USB adaptor, but there is a Camcorder-style 3.5mm jack on the plug that will take a 4 conductor A/V cord.

I thought techfreak was going to be doing something like that, but he is in turkey anyway so I may not have heard of it yet. He is with the turkey distributor.
 
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jokeman

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hi!
i thought, i show my bob too

the first version could hold 2 AAs to power the USB and you could mount it on the bottom of the GP2X
but it only had one USB port and it was a little bit fragile

the second version is much more robust and compact (ca. 40x60x20mm)
it has a mini USB hub inside
and i used four 3.5mm jacks, nubie mentioned
two for 5V-in and 3.3V-out... they are on the bottom of the box, so i can plug a battery pack on it... or a small 3.3V -> 5V converter... or simply use a power supply
then there is one jack for S-Video and one for Serial... i use a simple 3.5mm to DE-9 cable to connect the serial to PC and a 3.5mm to mini-DIN to connect the S-Video to TV
i also want to make a 3.5mm to USB to power the box with my laptop

and here are the pics:

bob v1
bobv1.jpg


bob v2
bobv2.jpg


the original usb hub i used
14251.jpg
 
T

TelcoLou

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yalborap posted on Mar 19 2007 at 03:57 PM said:
Yes. I would pay good money for a nice BoB that's portable.
 
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poddy

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yalborap posted on Mar 19 2007 at 07:57 PM said:
Yes. I would pay good money for a nice BoB that's portable.
 
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Alex.

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TelcoLou posted on Mar 19 2007 at 04:07 PM said:
yalborap posted on Mar 19 2007 at 03:57 PM said:
Yes. I would pay good money for a nice BoB that's portable.


poddy posted on Mar 19 2007 at 04:09 PM said:
yalborap posted on Mar 19 2007 at 07:57 PM said:
Yes. I would pay good money for a nice BoB that's portable.

I'd buy two!
 
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Hollow

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Jackd posted on Mar 19 2007 at 10:56 PM said:
That BOB is awesome!... what kind of cable do you need to plug in for tv out?
S-Video. S-Video cables are commonly round and have 4/7 pins and a plastic key.
 
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jokeman

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yalborap posted on Mar 19 2007 at 08:57 PM said:
Yes. I would pay good money for a nice BoB that's portable.
well... it took me about 8h to build this box (one of the hardest parts was to make the holes in the box)
say 15,-/h... 20,- for the parts (i couldn't find a cheaper cable) = 8x15+20 = 140,-
would you pay 140€ for this box? ;)
in mass production, i could build it faster... but nevertheless, it would be to expensive

nubie posted on Mar 19 2007 at 09:02 PM said:
Sweet!
Have you given any thought to this? (Go large/Album):
[...]
It terminates the USB in one simple chip. It is very tiny, perhaps too tiny though.
This is a cool tiny thing... i made my own termination board, but i definitive could use one of these
The problem is, that i have no idea, where to get this pice in austria/europe

Hollow posted on Mar 20 2007 at 12:11 AM said:
S-Video. S-Video cables are commonly round and have 4/7 pins and a plastic key.
jep... the S-video mini-DIN plug has 4/7 pins. But S-video actually only uses 3 wires: Ground, Luminance and Chrominance
so i use a 3.5mm stereo headphone jack, because it is smaller than the mini-DIN
to connect it to the TV, i used a 3.5mm connector, a 3-wire cable and a mini-DIN connector and soldered the right pins
 
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jokeman

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of course... i don't think, anybody would spend 140,- for this box...
and that's why a private individual can't make money with such a project
but... as nubie always says: it isn't hard to make your own box... it's only time consuming ;)
 
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