Understanding USB-OTG for custom Module

I thought it would be straightforward to buy a cheap Otg thing on Amazon and glue it to the GameShell when we get it, but noooooo…

I currently understand the basics of USB on-the-go:
5 pins, 4 for normal USB stuff, 1 for device ID.
If the device ID pin is closed, the host device will active host mode and use connected USB peripherals. If is open, the device will act like a USB peripheral.

Now, people have asked that HDMI, and USB type A ports be added to the GameShell, something which I AM NOT REQUESTING!

Instead, I am trying to find small OTG boards that could add that functionality in the form of a small DIY module to be attached to the GameShell (either through lego or by using that hole in back with some creative engineering).

I’ve found one for old samsung devices, but it requires an 11 pin USB-OTG, a thing that hasn’t been mentioned since 2015. I’ve also found MHL(Mobile High-Definition Link), that turns the USB-OTG into an HDMI out, but it disables any ability to also use USB.

So, I’m curious if you guys have any leads on a reasonable 5pin HDMI and USB otg connector, some magical wiring that makes things work for some reason, other alternatives, or just feedback in general, I’d love to hear it!

Before you comment @aewens: Yes, I have seen the superbook. It’s awesome, but wouldn’t fit on the back of the GameShell XD

TLDR: Trying to make a module for people that need USB and HDMI, have any ideas?


Have you heard of the - ah, never mind. As for the board you are mentioning, I happen to have a 5 pin board for a USB header on it’s own (which I’m planning to use to attach to a Raspberry Pi Zero W, but that’s a whole other thing). The one I got was from Amazon and should fit your needs nicely. Or were you referring to something else?

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That’s not quite what I’m looking for, though they were promptly added to my card because hell’s yes.

I’m thinking of like… you know these USB hub hats for the Pi Zero? Some kind of small board USB hub board I can wire my own Micro USB-OTG cable too. I guess, ironically, that example would work for that though…

I’m also trying to find a way to add HDMI out to the GameShell. People seemed interested in connecting their GameShells to their TVs. The only USB to HDMI stuff I can find is either obsolete or $70. I’m hoping someone could point me in the right direction, or tell me to wait for the GameShell 2.0 and sit down. (I’ll take no offense if you do that BTW XD)

PS: I promptly found this “recommended” to me when I clicked your link, it too is an appropriate size for adding a USB hub to the GameShell. I might well just use this.

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Should people be looking to make custom OTG solutions in the future (I don’t know, could just be me), I’ve found a couple of things that might make whatever your creations might be a bit more compact with a little bit of work.
90 Degree USB OTG up/down
OTG to USB Compact adapter

I figured that I’m definitely not going to be the last person thinking of modding the GameShell through the USB port (it is not too hard to setup, just need to find the right compact circuits), so I might as well put my findings on here.

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I happen to also have the OTG to USB Compact adapter pack sitting on my desk, too. The 90 degree USB OTG I somewhat have, but it’s to the right/left, not up/down (for the project their for, this is the more appropriate orientation). I’ll take a look and see if I can find something more suitable for your situation.

Maybe something like this? It uses pogo pins, so you can get away with using this without having to solder anything. It also has an additional port for another battery to be plugged in (that can potentially be used to add a second battery to the GameShell).

That might be perfect!
Going that route, I’ve also seen this on Kickstarter.
It only have 3 USB ports and doesn’t have the battery, but it has UART(Universal asynchronous receiver-transmitter) pins for adding sensors and the like if anyone is into that. Both of those are only 10 bucks, so I’ll probably try both of them by the time I’m done. I’m starting with the UART one because adafruit tried to kill me with shipping last time… :weary:

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I recalled you wanting to add additional battery to the GameShell in another thread, that being why I went with that one. You may be able to find the board elsewhere, that was just the first instance I found it from.

I’m still thinking about that, just throwing out ideas. Besides, I kinda forgot I kickstarted the other Pi hat until you sent the adafruit one, so I have something to model around in the meantime! :sweat_smile:

I might also just chop up some USB accessories and solder them together into some horrible/genius amalgamation and post it on here later… you never know

Speaking of the battery… there is some room under the speakers in the GameShell. So a custom extended internal module housing plus, as you suggested, a larger battery soldered to the existed module’s board might all fit inside. Food for thought

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Be careful tearing apart USB accessories for tinkering, after tearing apart 3 USB sticks I found they were unsuitable for soldering (hence why I purchased the breakout board). You also may not need to solder the battery to the clockworkPi board if the multi-purpose 14 pin port has a power and ground available that pushes enough voltage through, and can then make use of it.

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Thanks for the heads up, I’ll keep that in mind!

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You are right about the “ID” pin.

There is no way to make USB to HDMI, the protocols are really differents and HDMI use more pair of wires than USB. If you find a USB to HMDI it will be either a crap product (potentially dangerous because connecting things at random as I’ve seen in some Chinese adapters.), or something similar to the USB screen you find but without the screen, and that need specific driver, and will never replace a real HDMI output.

I don’t know what you mean by “11 pin USB-OTG”? Are you looking at USB-C connectors?

I’m not sure what you want with the Pi0 adapters, they are just USB Hub, and do nothing else, and there is no solution to have, from a single OTG USB port a dual device/host solution, that is one or the other, not both.

The mini USB on one of the Pi0 board you show is just a serial over USB for the Pi serial port, you can’t do anything else with that.


The 11 pin USB-OTG things were only for Samsung devices a few years back. I gave up hope on those. (Here is an example of that)
USB-C can only do HDMI&USB if it a thunderbolt 3 port if I recall.

Then, the only HDMI solutions, as you said, were either crap or similar to a USB screen. Annnnd they cost like, >$70.

The Pi hats, ignoring the other un-usable stipulations, seemed to make good compact USB hubs. Though the board in this is smaller and would work as well. The kickstarted pi hat, while larger than the average USB-HUB, has UART (for some serial fun) that I might take advantage of since I can’t have my USB and use HDMI too.

Thank you for confirming my fears. I figured I ought to see if there was a reasonable solution due to the couple threads talking about/requesting USB and HDMI. Looked bleak, but plausible.

Not exactly, there’s HDMI Alternate Mode for USB-C. However, USB-C also is a 24-pin port as opposed to USB-A which uses 4 pins. The drawback here is the the multi-purpose cable we are given to interface with the clockworkPi board is a 14-pin cable.

However, if you still want to try and make dreams come try, this is the breakout board for USB-C.

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Progress! Not guaranteed progress, but progress! Thank you, I will look into that.
(Huh, didn’t realize normal USB-C could do HDMI. I think I didn’t dig deep enough…)

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You will never be able to make USB (or even HDMI) by using GPIOs** so forgot about using the “free 14 pins” for USB or HDMI or anything like this.

But yes @aewens is right, USB-C have alternate modes and Thunderbold is one of the alternate mode, but DisplayPort (not sure in fact for HDMI) is another alternate mode and both are not linked.

Well it is probably too late, but Clockwork could have added a microHDMI connector to the ClockworkPi (the connector is about the size of microUSB B is not smaller.

** Unless these GPIO can be switch to USB of course

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Welllllll dang it.
Long/short of it: Stop getting your hopes up. Got it.

Thought about it, learned about it, learned it isn’t possible, put Idea down.
(Except the usb hub. I can’t screw that up.)

I keep referring to the “free 14 pins” because the only info we have on them is from the Kickstarter page and that they include “UART/I2C/SPI/GPIO”. I know I’ve seen UART to USB cables, but I’m sure of what capabilities you can really get from this because I recall this is usually intended for uploading files to routers and have not tried to use it as a long-term interface.

It’d be easier to reason about all of this if we knew what the pin-out was for this multipurpose cable, but when I asked Clockwork about it they told me it’d come with the manual in the GameShell’s packaging, so I suppose we wait until then.

(Also, @Godzil, it is aewens, not “awens”!!!) Thank you :relaxed:

Sorry :sweat_smile: it is fixed!


So what kind of cable/adapter could we use/buy? It is rather important for me that it can connect to screen/tv as I’d love to use the GameShell as a media center on the go as well :slight_smile: