# will this microsd reader work without external power?



## yeahman45 (Oct 16, 2011)

http://www.kickstarter.com/projects/andyfei/mini-microsd-reader-for-android-smartphones-and-ta?ref=category

check this out


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## AndroidLover (Apr 3, 2012)

At the bottom line: No, it won't. The lack of power from the MicroUSB Port of our lovely Touchpad will let this card reader simply stick "dead" in the receptacle.
If they use a USB chipset with an active USB hub chip integrated, it will at least work with an external power supply like a mobile battery and a USB Y-cable.

I am working on exactly this problem: I created a 2 port USB hub extension for the Touchpad which fits exactly in the SIM card slot instead of the plastic part which sits there factory assembled. This board incorporates an active USB hub chip AND an additional Li-Ion cell-to-5V power converter for USB power supply. As long as there is no device connected to one or both of the USB ports, the whole thing consumes virtually no power and is powered up automatically when one connects a device to one of the ports.

With this extension of mine, the card reader from your link will work of course with no additional cables or batteries needed.


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## drmarble (Jan 19, 2012)

In fact, the touchpad requires a 5 (3.7?) volt signal to wake up the serial port. Even if the external device has power, you need to feed some to the touchpad too. Sorry, we really do need the y cable or something similar.


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## AndroidLover (Apr 3, 2012)

DrMarble,
the TP itself needs no power feeded for USB communication. Tie the ID pin to GND (short Pin 4 and Pin 5) to put the TP into host mode and connect an external powered USB device like a R/F mouse transceiver only with GND, D+ and D- to the Touchpad and you will see, the mouse works (as long as the R/F transceiver is powered through an external battery or something similar).
The USB port is always active, it needs no wake up signal. The ID pin is only to switch from device to host mode. No other signaling is needed. Only GND and the data lines for communication are needed for proper operation with an external powered device. But not all devices are working when externally powered due to the standard 100mA limit of the USB standard. Every device which negotiates for more current will be switched off by the USB hub chipset of the Touchpad, even if the device is powered externally and there is definitely more than enough power feeded to the device. Therefore only devices with less than 100mA of current will work in general with external power applied, so keyboards and mice will work. But no card-readers or Thumbdrives or anything else with more power will work due to the fact, that the Touchpad shuts down the port (it doesn't support host mode with power supply natively).

That is the point where my extension boards comes into play: it connects a USB hub as a so called 'detachable self-powered hub' to the Touchpads' side (which of course consumes less than 100mA) and delivers 2 USB host ports to the user in parallel with the power feed of internally (from the Li-Ion battery) generated 5V (yes - it has to be 5V, 3.7V are not enough).

I'm sure you know about the dozens of YouTube videos where people show the use of an external USB hub and a Y-cable with a battery for power feeding the USB hub and all connected devices. That's the same thing like what I'm doing with my extension board, just dramatically shrinked in size so it fits into the SIM card slot.


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## yeahman45 (Oct 16, 2011)

lol i am totally lost in these technical terms lol ... what is this extension board? is it custom made or can it be bought or something?


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## AndroidLover (Apr 3, 2012)

Hi!

The extension board is actual an engineering sample of mine, which I designed to compensate for the lack of USB host ports which HP "forgot" to design into our lovely Touchpads.








I called it extension board because it extends the USB functionality of the Touchpad from the one built-in USB device port to two additional USB host ports with no need for external power. Actually I am in the prototyping stage of the design and have verified the power-converter (Li-Ion battery to 5V for USB) successfully with efficiency up to 93%. I expect the complete board to be verified and ready for building-in into the Touchpad in the next two weeks.

If anyone has interest in it, one can leave me a PM. But of course we are talking about a piece of hardware - so one needs to open the Touchpad and solder some wires for battery and USB connection. Good soldering experience is definitely necessary! This isn't a "flashable upgrade"!


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## yeahman45 (Oct 16, 2011)

sounds really interesting, unfortunately i don't have any soldering knowledge


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## nevertells (Oct 29, 2011)

yeahman45 said:


> sounds really interesting, unfortunately i don't have any soldering knowledge


This is definitely not a project designed for the technically challenged.


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## Colchiro (Aug 26, 2011)

NT, you up for it?


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## nevertells (Oct 29, 2011)

Colchiro said:


> NT, you up for it?


Only way I would crack open a TouchPad is if I thought it needed a new battery. I was an electronics tech for 21 years in the Air Force, so I've been known to tackle some pretty crazy electronic projects. On second thought, you've already done this, so I'm sending it to you.


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## Colchiro (Aug 26, 2011)

I only broke half my clips the first time.....


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## AndroidLover (Apr 3, 2012)

I think, one can open it without big hassles if one has the right tools and the exact knowledge of the correct position where the clips are located. Then this would be not a big deal. The soldering itself would be a bigger problem. Some skills are needed for this of course. But in my opinion the result is worth all efforts.









€dit: I can make some photos and a small "guide" for opening and accessing the correct solder points for this if anyone is interested...


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## nevertells (Oct 29, 2011)

AndroidLover said:


> I think, one can open it without big hassles if one has the right tools and the exact knowledge of the correct position where the clips are located. Then this would be not a big deal. The soldering itself would be a bigger problem. Some skills are needed for this of course. But in my opinion the result is worth all efforts.
> 
> 
> 
> ...


Is this the same project you have been posting about over in XDA? If so, just provide a link, if not, lets see your stuff.


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## Mpgrimm2 (Dec 6, 2012)

I've been pm'ing AndroidLover about this project of his for a while and must say minus the microUSB vs full size Usb (just preference really), it's gonna be a work of art based on the design previews I have seen. Best of all you won't have to "dremel" /thin out the back of the case to get it in there like I did with mine (A.L's board has more smarts than my setup too). 
Looking forward to seeing the finished project.

Sent from my "Up all night, Sleep all day" EVO3D!


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## AndroidLover (Apr 3, 2012)

@mpgrimm2: Thanks for the compliments!








@NT: I think not, because I did never post over @ XDA although I am registered there. What I did in the past is - if ever - posted @WebOSnation.com:
http://forums.webosnation.com/webos-accessories/314741-how-get-full-power-charge-mobile-battery-car-hp-touchpad.html

Several interposer adapters, cable adapters, tested dozens of devices for connection/performance and so on. Finally I built up my own "Mobile USB charger" (pics in the thread available also) where I kept especially the Touchpad in mind, so it would be possible to fast charge the TP @2A and on the road, with solar panels and not only the Touchpad but nearly every mobile device which has a USB connector...









All this stuff (and of course the acitivies of Mpgrimm2 with his mod for USB) leads me to again build an own design for powering USB devices from within the Touchpad itself. Successful. Although I posted this "intermediate" design nowhere. The actual design which I am talking of here is a further development based on the intermediate - power only - design, where I now combine the successful verified power converter with an additional USB hub chip to overcome the 100mA limit of the Touchpads' host controller. That's where I am at today. Have to verify the new design like I did with the previous one.
Pics here: http://sdrv.ms/ZQXwjG

If everything goes well, it will be possible to connect every USB device (normal mice, R/F mice, keyboards, R/F keyboards, thumb drives, card readers, HDDs and SSDs - others also possible). As long as the installed Android kernel will support the connected device it will work.

Call me crazy - but development of the Touchpad is not only limited to software. I do it in hardware also!


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## nevertells (Oct 29, 2011)

Mpgrimm2 said:


> I've been pm'ing AndroidLover about this project of his for a while and must say minus the microUSB vs full size Usb (just preference really), it's gonna be a work of art based on the design previews I have seen. Best of all you won't have to "dremel" /thin out the back of the case to get it in there like I did with mine (A.L's board has more smarts than my setup too).
> Looking forward to seeing the finished project.
> 
> Sent from my "Up all night, Sleep all day" EVO3D!


+1


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## AndroidLover (Apr 3, 2012)

Sorry MPgrimm and NT, but there are slight delays at the moment from my side (various personal reasons). Thanks for following up my project.

Good news are: the first engineering sample performs very well without any modifications, so it meets all requirements I designed it for and the goal is within reach. I'll have to assemble it into the SIM card slot and do the wiring (which I still have to figure out) and make some photos of it for the community.









I'll be back soon - stay tuned!


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## AndroidLover (Apr 3, 2012)

OK Ladies and Gentlemen - here we are today:

Worlds first 2 port USB Hub with integrated power designed exclusively for the HP Touchpad:
























Unfortunately I have to do the tests on another mainboard than the one seen on the photos, because this mainboard I had chosen has a faulty USB-ID line (cannot switch into USB host mode - hahahaha). So I have to reassemble the USB Hub into another Touchpad with a working mainboard first.

Next step is to test this with another mainboard and get results of testing keyboards, mice, thumb drives up to 64GB and HDDs/SSDs up to 500GB. I will report back asap.


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