Replies to This Discussion

Permalink Reply by Fête Mobile on July 19, 2012 at 10:30pm

I bought two minimOSD modules: a 0.1 and the 2.0 version (with the switching regulator). Just before my second flight out I fried the 2.0. I hadn't read the warnings from this thread but suspected a grounding loop fried it. I was, needless to say, a bit miffed. I had powered the video system before powering the ESC.

What's the point of making a super-small OSD if it requires a dedicated battery? I got it for small drones, after all. I hope that someone can solve the self-destruct hardware flaw as the firmware is coming along nicely.

I have been using the v0.1 model (powered by the APM). As a precaution, I now power up my drone as follows:

* Power to the APM/ESC (via deans plug)
* Power to the video system (via the balancing header)
* Wait a few seconds and cycle power to the APM, as the minimOSD won't boot otherwise.

As an additional bit of OSD flakiness, I note that if I power up the OSD and am getting good video, but then take off the lens cap, I lose the OSD. Cycling power to the APM brings the OSD back. I'm going to test this bug more tomorrow as it sounds a bit too strange to be true.

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Permalink Reply by Gábor Zoltán on July 20, 2012 at 2:25am

It does not.

Simply power it from APM. ;)

Also, don't use the middle pins on your video cables. (No + wire to MinimOSD trough video connectors, just signal and ground)

Link

That is all ;)

Gábor

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Permalink Reply by RotoGoat! on November 4, 2012 at 6:20pm

I have a similar problem on my v0.1 board

I am running +5 off apm as you are. I have removed centre pins on the analogue side also. There is a blob of solder over the "PAL" jumper.

OSD reads mav data and boots normally. I get osd with no video, but as soon as video is fed to it, the osd is gone.

Its got me stumped! Is there new code to fix it?

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Permalink Reply by Fête Mobile on July 23, 2012 at 7:09pm

I did a bit of testing and can confirm that using a V0.1 minimOSD powered by the APM works. I haven't fried this OSD (at least not yet), but have been careful to power up the APM before the video system. I have added solder blobs to the back of the board to tie the analog and digital power rails, and have removed the V+ pins from the pin headers that connect to the video in/out connectors.

I'm not sure why this is, however, but I have to cycle power to the APM after the minimOSD boots up. Otherwise, I just get the video passed through with no OSD at all. Can anyone comment on why this might be or other workarounds?

I'll keep testing with this miniOSD and hope I don't fry it. I hope this hardware flaw is repaired so the minimOSD firmware can continue to improve.

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Permalink Reply by Gábor Zoltán on July 24, 2012 at 12:24am

I think you have a PAL camera.

If Minimosd does not see any video when it boots, than it defaults to NTSC.

If it is the case, you have 2 choices.

1./

Simple way is to lock Minimosd to PAL only.

In Arducam_Max7456.cpp

search for:

else setMode(0);
digitalWrite(MAX7456_SELECT,LOW);

than change setMode(0); to setMode(1);

2./

You can make it default to PAL and still have the possibility to use a NTSC cam:

Go to the same place:

#endif
else setMode(1);
digitalWrite(MAX7456_SELECT,LOW);
}

tahan add this after #endif

if ((B00000010 & osdstat_r) < 1){
setMode(1);
digitalWrite(MAX7456_SELECT,LOW);
}

So your code looks like this:

if ((B00000001 & osdstat_r) == 1){
setMode(1);
}
else if((B00000010 & osdstat_r) == 1){
setMode(0);
}
#ifdef MinimOSD
else if (digitalRead(3) == 1){
setMode(1);
}
#endif
if ((B00000010 & osdstat_r) < 1){
setMode(1);
digitalWrite(MAX7456_SELECT,LOW);
}

else setMode(0);
digitalWrite(MAX7456_SELECT,LOW);
}

Hope it helps

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Permalink Reply by BR928 on July 24, 2012 at 4:27pm

 

My 3rd MinimOSD is supposed to be on its way after blackscreening (fried) the first two. 3DR can't tell me why this is happening and went as far as telling me I can power the APM (digital +5V Mavlink) and the video side of the OSD (+12V analog) from the same battery. This is the configuration that destroyed the first two. This time I am going to try tying the analog and video together like you did. Are you just using the video in/out pins or do you also have to use ground on the video side?

I, like you, am nervous about ruining another one not knowing what’s causing it. It seems like using two separate batteries was never a problem.

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Permalink Reply by Gábor Zoltán on July 25, 2012 at 12:32am

Hmmmm.....  I have read about this problem. so i decided to use the 5v fom mavlink.

On the video connectors, i do not use the middle pin. only video and ground.

I do not have 2 battery on board anyways. Using one for all.

It works great for me. :)

Hope you will be happy with your 3rd MinimOsd! ;)

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Permalink Reply by Andre S on July 25, 2012 at 12:57am

About the power issue: the reason why for some people different solutions work, could this be caused due to the revision of the hardware that (as I read somewhere) involved a change of the voltage regulator?

Just a thought.. I'm planning to use separate batteries but I wonder why using the same would cause problems. Maybe a diode missing somewhere?

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Permalink Reply by Cala on October 6, 2012 at 6:03pm

Don't you have any kind of interferences on your video like horizontal lines, servos,etc.? Are you using some kind of filter?, I'm using one battery powering both sides but the minim becomes very hot, I don't like this anyway :(

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Permalink Reply by Fête Mobile on October 7, 2012 at 10:32am

Hi Cala.  If your MinimOSD is getting hot, I suspect you are using the V0.1 hardware with the linear regulator.  You will probably soon fry it if you're not careful.  As others have said:

* Remove the +12V pins from the Vin and Vout headers. 

* Put solder blobs on the board so it is powered from the APM +5V.

* Make sure the digital and analogue grounds are tied together (a solder blob on the back of the board).  A difference between these, such as is transient when connecting your motor, is the main cause of death, AFAIK. 

* Yes, you may get interference from the motors/servos.  You may need to add capacitors or a good L/C filter to smooth these out and you probably won't be able to 100% eliminate them.  Better noise than a dead MinimOSD, I always say!

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Permalink Reply by Cala on October 7, 2012 at 12:15pm

Ahh!!!!, I have 0.1....FIUUU!!! I've just save my minim Thank's!!! :)

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Permalink Reply by gustavo on April 6, 2013 at 6:05am

Fete,
After reading all recommendations and still not having a clear view of which is the safest way to power the minimosd , I would like to ask if your post is still valid, and you do recommend go this way,

Would very much appreciate your experienced advice,

Gustavo

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