Backpack help

jdolecki · 2011-11-21 07:52

Once i load the "PropBP_overlay_demo.binary" into my back pack ee prom

What do I do next as no demo seems to run?

I know is a general question but i spent 4 hours beating on this but didnt get any were.

Is there a better tutorial i can use to leard this overlay stuff.

Thanks

john

Phil Pilgrim (PhiPi) · 2011-11-21 08:08

John,

The overlay stuff requires an external video source, such as a camera, before anything will appear on the screen. Do you have such a source connected? Also, both jumpers (VID and OVL) need to be installed.

The documentation in the overlay zip on the Propeller Backpack product page includes everything you need to know to get going. But come back here if you have any more questions.

-Phil

jdolecki · 2011-11-21 08:16

The image from my Gopro seem to pass through it and display on the monitor.

Both jumpers are installed

Phil Pilgrim (PhiPi) · 2011-11-21 08:37

So you're getting a camera image but no overlay? Maybe you've got the camera and monitor connections swapped. If switching them doesn't work, remove the OVL jumper. If you still get video pass-thru, there's a problem with your phone plug to RCA adapter (non-stereo perhaps). If the pass-thru goes away, replace the OVL jumper.

If you've reached this step without success, you might be having a sync problem. I don't know where you're located, but your GoPro needs to be outputting NTSC (not PAL) video for the overlay to work. Also, some cameras do not output the correct video levels when not driving a 75-ohm load. This will cause the Backpack to lose sync when attempting opaque overlays. If you suspect that this could be a problem, switch to transparent overlays only in the demo code source by altering the following line (near the top) to read:

  TPT       =    1

-Phil

jdolecki · 2011-11-21 08:51

Chicago

Will try when I get home from work around 4pm.

Thanks

jdolecki · 2011-11-21 09:01

My camera shoots the following video resolutions:

Does image size and fps effect sync?

resolution fps screen resolution

1080 - 30 1920-1080

960 - 48 1280-960

960 - 30 1280-720 (Default the one im using)

720 - 60 1280-720

720 - 30 1280-720

Phil Pilgrim (PhiPi) · 2011-11-21 09:14

Are you getting your output for the Backpack from the combo TV/Audio connector on the GoPro? Have you selected NTSC (vs. PAL) in the setup menu? If so, you should be getting an NTSC signal out. That signal won't have any of the aforementioned resolutions, but something much reduced to fit the bandwidth of an analog TV.

-Phil

GordonMcComb · 2011-11-21 11:25

Phil is of course the go-to guy for all things Backback, but your original post plus some of the responses have me wondering about some things.

First, none of the resolutions you have listed is NTSC, so assuming the camera has an NTSC output and you've set it to NTSC then its down-resing may not be a clean enough NTSC for the Backpack. The Backpack requires much tighter conformity to NTSC specs than most video monitors, which are able to latch to a wide variety of syncs and resolution.

An easier way to test is to take the video output (the yellow RCA jack) of a VCR or DVD player, as that's bound to be pretty good NTSC. If that works, but your camera doesn't, then you can narrow down the problem to the camera.

Second, your original post didn't indicate if you've gotten the Backpack to work in non-overlay mode. Could you confirm? You'd want to do that first to assure you've set up the proper communications between your controller and the Backpack.

-- Gordon

jdolecki · 2011-11-21 11:57

I have the camers connected tru the tv/audio jack ---- not the hdmi one

Its on NTSC to

I will do the thing Pi said when I get home from work and will post the results later

thanks everyone for the help

jdolecki · 2011-11-21 13:31

When I remove the OVL jumper the camera image goes away

but the text on the demo just scrolls/binks? on a blank screen?

Phil Pilgrim (PhiPi) · 2011-11-21 13:46

Okay, put the OVL jumper back. At least we know now that your phone-to-RCA adapter is okay and that you don't have its input and output swapped. With the jumper back in place, do you see any characters or partial characters being displayed? If so, where? Just near the top?

-Phil

jdolecki · 2011-11-21 13:59

I cant see anything

jdolecki · 2011-11-21 14:03

Do i load the PropBP_overlay_demo.binary into ee prom

Do I load anything else?

Phil Pilgrim (PhiPi) · 2011-11-21 14:15

jdolecki wrote:

but the text on the demo just scrolls/binks? on a blank screen?

jdolecki wrote:

I cant see anything

Am I to understand that you see text with the jumper removed, but not with it installed?

jdolecki wrote:

Do i load the PropBP_overlay_demo.binary into ee prom

Yes, but try it using the source code instead, in case we have to modify the constant I told you about.

-Phil

jdolecki · 2011-11-21 14:20

I dont know if a video of the screen will help

http://www.youtube.com/watch?v=xnETKxYnDB4

Phil Pilgrim (PhiPi) · 2011-11-21 14:38

That's weird. The overlay characters are there, which means the Backpack is syncing on the GoPro okay, but the TV is not syncing on the resulting video feed. What happens if you yank the VID jumper? Do you have a video source other than the GoPro that you can try it with?

-Phil

jdolecki · 2011-11-21 14:45

taking the vid jumper out did nothing

Phil Pilgrim (PhiPi) · 2011-11-21 15:04

Do you get a steady picture with the GoPro plugged directly into the TV/monitor? If so, try the overlay using a different video source with the current TV/monitor and using the GoPro with a different monitor.

-Phil

jdolecki · 2011-11-21 15:20

When I use my DVD player as an input to my TV it the demo runs

I took the TV out and plugged in my small 12v monitor and it works.

Plugged in the GoPro and stopped so the GoPro is the issue

Any ideas

Im updating the firmware on the GoPro and trying it again

Phil Pilgrim (PhiPi) · 2011-11-21 15:49

Again, does the GoPro produce a picture on the TV or monitor when directly plugged into it? If not, are you absolutely sure you've got it set for NTSC and not PAL?

-Phil

jdolecki · 2011-11-21 16:23

Yes the camera will work on the 12v monitor when plugged directly into it.

Camera is set for NTSC Not PAL

Phil Pilgrim (PhiPi) · 2011-11-21 16:25

Okay, go up to post #4, and make the change I recommended there to see if it helps.

-Phil

jdolecki · 2011-11-22 01:49

Setting a 1 or a 0 has no effect

I will try a different camera tonight

thanks for all the help

jdolecki · 2011-11-22 05:20

Phil

Found this on an RC fourm They are using the GOPro with another OSD board

The gopro has to high of an impedance level to work with the Hoverfly board. Don't quote me but I recall the Gopro level being around 100 ohms when most video signals are around 50 or 75 ohms. Assuming you have the correct update for the gopro board to get the live video out (which is terrible quality) and you have it hooked up correctly to the hoverfly board, it will either give you no signal or you get a signal but the OSD will flicker all over the screen. I have the same problem on my range video OSD which I had to remove a resistor from the board to get the signal right. In the end, bypass the hoverfly OSD or use a second camera with the right impedance.

And another post said just add a 75 ohm resistor accross the video leads from the GoPro.

Phil Pilgrim (PhiPi) · 2011-11-22 09:01

That's what I suspected. What happens is that when the camera's output is cut off from the monitor's load resistor (i.e. during overlay character display), its output voltage soars. This causes conduction through the protection diode on the Prop's sync sense pin which, in turn, discharges the bias cap that holds the threshold voltage between sync and signal. When that happens, the Prop loses sync.

Adding a resistor in parallel with the camera's output should help. It doesn't have to be as low as 75 ohms. I'd start at 150 ohms and work down from there.

-Phil

jdolecki · 2011-11-22 09:52

I dont know what all that means but I will try a resistor tonight.

Thanks again for all the help

jdolecki · 2011-12-05 12:41

I finally go a different camera to try and no luck. (Just a regular security camera from frys)

Camera directlly to monitor works

Camera to BP to monitor works

The overlay still blinks on the screen if at all.

Any Ideas?

Do i load the demo program into eprom or ram?

What is that binary program I read about that it says to load?

Im sure i'm missing something but my head hurts working it any more?

Any ideas?

Phil Pilgrim (PhiPi) · 2011-12-05 13:19

It's still not getting a reliable sync, for some reason. Do you have an oscilloscope? If so, take a look at the signal from the camera without a load. What is the peak-to-peak voltage range?

The demo program can be loaded into RAM or EEPROM; it doesn't matter which.

-Phil

jdolecki · 2011-12-05 13:37

What cameras have you tried that you know work with it.

thanks for all the help

john

Phil Pilgrim (PhiPi) · 2011-12-05 14:08

John,

I've got one that works: an old Sony CCX-Z11, which outputs the correct 2V peak-to-peak with no load; and one that doesn't: a cheap board-level camera that outputs 5V peak-to-peak with no load. Both output 1V peak-to-peak with a 75-ohm load, but that load (in the monitor) is not seen by the camera when its output is gated out during the overlay process. If the camera's voltage during that time goes too high or too far below zero, the cap on the Backpack that holds the sync threshold will discharge through the Propeller chip's protection diode, and the Backpack will lose sync. It's important to use a camera with the correct output impedance that outputs a 2V P-P (unloaded) signal.

With a scope, it's easy to tell whether a camera meets those requirements. Before you buy another camera, we need to establish whether or not the camera you have meets spec. To to that, it will be necessary to look at the signal on a scope.

-Phil

Backpack help

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