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Mr.RC-Cam

MyVu Personal Media Viewer Glasses

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A few days ago woot.com had the MyVu Personal Media Viewer glasses on sale for $50. I thought it would be interesting to hack it for general purpose use. It has a 5th Gen iPod connector on it. I don't own an iPod, so I am flying blind on this one.

p679MYVUSO-f.jpeg

Well, it arrived today and I reverse engineered the 30 pin connector. Basically I popped open the user control pod and unsoldered the iPod cable. Between the silkscreen text and some online technical details to the 30 pin iPod interface, I was able to ID everything. Only ten signals are used on the glasses.

I've got it wired up and feel decently confident that everything is correct. The signals I'm using are Gnd, AVGnd, +3.3VDC, Vid-In, Aud-R, Aud-L. However, it does not power up. One important clue is that it draws a low standby current (0.5mA). What has me worried is that there are two communication signals in there, which makes me wonder if the iPod needs to talk to the glasses before they turn on. I don't have anything connected to these signals since this hack is all about converting the glasses to work without an iPod.

So, if anyone has a pair of these and an iPod, can you tell me what you do to turn them on? Do they come on as soon as the iPod is turned on, or do you need to push a button on the glasses? Anything you can share would be grand too since it may clue me into where I went wrong.

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Don't know anything about them myself, but you might try taking a 470k (may have to work down in value) resistor and bridging those unused contacts to + and/or ground. That may possibly start them up. Sorta like PC power supplies that need to have a load on the 5 volt rail before they'll supply any voltage or current...

Just thinking............ I'm guilty of that occasionally...

Edited by W3FJW-Ron

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Hi,

Don't know if you are aware of the MyVu 'Shades' glasses (they have the screen angled down so you can look over the screen and see whats going on around you - perfect for flying!!)

[url="http://www.myvu.com/Shades.html"

They make two versions, one is for iPod and on is called the 'universal' and allows standard video to be connected. The reason I mention this is I think the only difference is an adapter lead that plugs into the iPod input and has standard phono inputs for video and audio. If this is the case, you may well find it will work for your glasses. There's a customer helpline listed on the website - might be worth a call and if it works thats a lot of grief saved!!

All the best!

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That one has an awfully narrow field of vision. Only 16.9 degrees. I would think it would be like having blinders on when using for FPV. FOV is about 4+ times that with a camera.

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Thanks for the help. Hopefully I find more time today to poke at it.

BTW, the universal connector setup is different than what I have, so it won't work with it. On my unit the cable is hardwired, so it cannot be unplugged and swapped with their composite cable. This product is suppose to only work with a 5th Gen iPod. The trick is to beat it into submission to work without the iPod. :)

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I spent more time with it and still no joy. At this point I wish I had tried it on an iPod before the hack, just to see if it worked out of the box. The odds are that it did, so my lack of success probably means I haven't found the hack's magic solution. I'll hang tight and hope someone else gets further than me and tells us about it. :)

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I still haven't found a documented hack to convert the goggles. However, EE Times published a teardown, so here's what is inside (the PCB that is shown is the item I have been attacking):

DC1504_UTH_PG_36.gif

Full teardown article: Click Me!

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What about searching for info on the ipod and see if someone has already had a look at what kind of communication was going on on the 2 data wires?

Or borrow an ipod and do it yourself :P

Edited by Kilrah

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look up the TW9910 and find video input pins,

the MSP430 is simply for the buttons, might not even be needed ?

the stepdown converter will reveal power in and out

the MSP430 run on 3.3V normally so that will also help you finding power pins.

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All very good ideas. :)

My original hope was that the modifications would not require significant reverse-engineering. If I don't see something published in the next few weeks I'll go at it on my own.

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A few thoughts on this:

The KCD-A210-BA display controller requires having configuration registers set and being initialized before being used. This is performed by the MSP430F2131 microcontroller through a serial data interface.

The TW9910 video decoder also requires having configuration registers set and initialization before use. This is also performed by the MSP430F2131 microcontroller through a serial data interface.

The MAX9723 headphone amp is connected to the MSP430F2131 through a serial data interface to control volume.

The MSP430F2131 reads the pushbutton switches and sends the commands to the proper chip.

The MSP430F2131 connects to the serial bus on the iPod. It may read data from the iPod or it may read & write. Apple Accessory Protocol

From these observations it appears that the MSP430F2131 microcontroller is in charge and to wake up the MyVu, the MSP430F2131 must be woken up. One way that this may be done is have the MSP430F2131 listen to the iPod serial bus for chatter. If there is activity, the iPod is turned on and the MSP430F2131 could wake up. If this is the case, then you could connect a 4.7K resister from iPod TX to Vin & a 4.7K resister from iPod RX to Vin (as per W3FJW-Ron's idea) to wake up the unit.

The MSP430F2131 could also be listening for a certain bit of data/command from the iPod to wake up. If that is the case, a PIC would need to be programmed to send the wake up command or the MSP430F2131 would need to be reprogrammed to bypass this.

Pinout for the iPod cable inputs on the remote PCB

(Cable comes in from left, pin 1 is at the top)

1. RFM - connected to AVGND

2. IPOD DF

3. Right Audio

4. AVGND

5. Left Audio

6. Unknown (looks like a video signal input)

7. VID

8. IPOD TX

9. IPOD RX

10. VIN (+3.3v)

11. GND (power ground)

A note on "6. Unknown (look like a video signal input)" - This connects to the TW9910 video decoder through a capacitor. That would indicate that this is a video related analog input, possibly part of a S-video input?

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From these observations it appears that the MSP430F2131 microcontroller is in charge and to wake up the MyVu, the MSP430F2131 must be woken up. One way that this may be done is have the MSP430F2131 listen to the iPod serial bus for chatter. If there is activity, the iPod is turned on and the MSP430F2131 could wake up. If this is the case, then you could connect a 4.7K resister from iPod TX to Vin & a 4.7K resister from iPod RX to Vin (as per W3FJW-Ron's idea) to wake up the unit.

In my earliest bench work I found that pulling the dongle's Rx line high for a moment caused the '430F to wake up. It would then begin to transmit host data (a short byte sequence about twice a second). But, as we can only guess, there must be an expected host response that is missing. And yes, I had tried other forms of innocent torture, but such simple acts did not cause any joy.

I'm still patiently waiting for someone else to find the silver bullet. Honestly, I've got so much going on that I don't know when I can spend the quality time needed to reverse engineer the little bugger. So, fingers are crossed that someone else does the leg work and publishes the juicy details. But in the meantime, please keep the ideas flowing. :)

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In the simple act of innocent torture, did you try to tie the TX and RX lines together? We never know, maybe the ipod only repeats what it has received...

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In the simple act of innocent torture, did you try to tie the TX and RX lines together?

Yup, had done that too. :)

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From member RetroPlayer at www.teamhackaday.com :

"Here's how to connect any composite video source to these MyVu "fully loaded edition for Ipod 5th gen only" personal video viewer (that's a mouthful!)

Simply pull up the Ipod_Tx line using a 100 ohm resistor between it and the 3.3v input. Make sure that REM_SENSE and IPOD_DF lines are left floating. Especially, Ipod_DF which will try to initiate communication with the ipod if it is pulled low.

Also, you must have both audio and video present in order for the glasses to turn on and stay on. When video or audio is lost, the glasses will turn off. If you press the brightness button for a second or so and release it, the glasses will power back on.

The pullup needs to be present already when you supply power. This tells the processor not to emulate an Ipod remote.

That's all there is to it. Well, except for supplying 3.3v that is.

I can't really take credit for this, because I cheated and called myvu. I was only looking for some hints, but I was transferred to the engineer that designed these, who was extremely helpful and interested in helping out.

This model uses the same base hardware and firmware as the solo edition (not the solo plus) so this mod should work for the ipod version of that as well. The fully loaded just added the battery pack and ipod sleeve, I believe.

Now, since these glasses actually use two cyberdisplays, I would love to see a stereo video mod. It may be possible to control which display is on and sync it with alternating video frames for each eye."

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Simply brilliant -- I've got working glasses. :) Thanks so much for forwarding the golden solution!

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Now Mr RC, you have to let us know how they are. User report & parameters please....

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Well, they are comfortable and draw very little current (80mA). Image wise, they seem perfectly acceptable as simple 320 x 240 glasses. For our R/C video app, they would fine for camera operators or entry level FPV. Other than that, you'd really need to put on a pair to see how you like them. You could probably demo these glasses (or one with similar pixel count) at a local store that has iPOD accessories.

As a hackable item, I give it two thumbs up. But if the user wants high-end video, then this is not the solution.

BTW, using an ohmmeter I found that there are existing pads for a SMD 0402 sized resistor on the back side of the board. The smallest 100 ohms I had was 0805, which was way too big (0402 is the size of a Tick, the 0805 is half the size of a grain of brown rice). So, I added a tiny through-hole resistor to the PCB's cable pads instead. An easier method would be to just leave the existing cable on and hack it instead of the PCB. I recommend that instead unless you are a glutton for punishment like me.

I should have taken photos. I'm afraid to tear apart the dongle another time since it has taken a horrible beating and it has already lost one plastic snap lock. But, the information discussed in this thread has all the juicy details to doing the mod. If anything is not clear, then feel free to ask.

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Many thanks. Something like that would fit my purposes nicely. Guess I'm gonna have to get off my butt and chase a pair down. The $250+ jobbies just aren't in my SS budget.....

Thanks to all for the info.....

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I woke up today thinking that someone needs to create a custom PC board with mating iPOD connector and 3.3V Vreg, along with the 100 ohm resistor. That would make this a painless plug-in hack.

Not that I need another PCB to layout, but I'd do it if there was substantial interest. Perhaps $20 or less for a nice PCB for DiY builders?

So, vote here and I will see if the response warrants the trouble. Please make your interest known in this thread -- don't send me a private message or email me. That will help me keep track of who wants one if I do the project.

Edited by Mr.RC-Cam
removed reference to kit.

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I'll jump on that (parts soldered)like a hound on a ham bone if I can find an inexpensive pair of "Goggles" to use with it. Haven't looked yet, but just off the top of your heads, does anyone have any idea what the IPod viewers cost??

Edited by W3FJW-Ron

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Thanks for the link Kilrah. Can't afford it til next month, so booked marked his store. He also has another one for use with 5th generation I pods for $75 but no specks included in the listing. Is 320X240 a large enough viewing area ? or are there larger ones available?

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The viewing area doesn't depend on the resolution, but on the field of view. The FOV seems to be specified at 16.8°, personally the smallest I've used was 22° and I already found it too small to enjoy, at this point if not for the closed view an LCD would actually be better IMO. But on the other hand on the listing the guy doesn't really know what he's writing, so I'm not sure one can really believe it... If Mr.RC-CAM says it's OK, I'd rather believe him.

Resolution effects the amount of detail you'll be able to see in the goggles, and the 2 values together will define how muck you'll be able to see the individual pixels.

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If Mr.RC-CAM says it's OK, I'd rather believe him.

My recommendation is based on the $50 Woot purchase. For that price, I give this hack two thumbs up. If someone had to pay much more, then I'd recommend to keep saving and buy some $400 glasses that have higher res and just plug in.

The glasses would be fine for a camera operator to setup the aerial shots. Or perhaps entry level FPV or virtual passenger viewing. Or maybe for just hooking to a TV for private viewing.

Despite essentially no interest, I went ahead and created the custom PCB for a painless plug-in interface. I should have something to show in a week or two. The one thing I'm not looking forward to is that I have to tear out my working hack and reconnect the factory cable. I hope my little dongle survives all the abuse (the plastic case is getting a bit ragged).

BTW, if anyone sees these glasses on sale for $50 again, then please let me know!

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