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Hello!
I dont know how to describe the problem better then call it a “running image”
I took the pal-demo and tried the whole thing with a cam signal and overlaying and the image created by the arduino was running across the screen – fast from left to right and slowly from top to bottom.If I use sync only with sync created from D9 everything works fine. What can I do to get a real “still” image on my screen with activated overlay?!
Greetings
bobhmm, that sounds like there’s a connection problem somewhere. The Arduino isn’t getting the interrupt when a new line is starting. Did you solder it yourself or buy assembled? You are in a PAL country, right? That is, your video source is a PAL signal?
Hello Michael!
Yes, I’m in PAL country and I have a PAL video source 😉
I soldered it by myself and I have an arduino mini not an UNO but taking account of the datasheets the ports should working as expected.
Where can I start to search?Attached you can find a short video – first with sync from video input and the last seconds with sync from D9
OOps, attachments are not possible?!So here is the link to the video:
https://drive.google.com/file/d/0B7MPaRLM-PfcR1gxVTFKNG5NTjJpZURtLTFIYW51SkNJQWNJ/edit?usp=sharingI’d check the connections with D8 and D2. You are not getting the external interrupt needed for the horizontal sync. Pin 1 (SYNCOUT) on the LM1881 is connected to D8, and pin 3 (VSYNC) is connected to D2.
Hm, I checked the signal directly at the pins of the arduino (tested now with an UNO)
The *-0001.png is taken from pin8
and the *-0002.png is taken from pin2Maybe the syncout is not in the right shape? I dont know how it has to be. Maybe the 1881 is broken?
How many different video sources have you tried to use? Try others.
Have you adjusted the small potentiometer to the lowest position?
Did you buy your kit directly from nootropic design?I’ve tried 3 different video cams, all with the same result.
Nothing changes if I adjust the potentiometer.
And no, I’ve bought all parts separately with your schematics as base – for R4 I’ve tested different potentiometers as I could not find a value for this. But many different sources on the internet say that it should not be necessary and they work with the 680k only. So do you think, it is necessary?My idea is, that something is wrong with the lm1881 because if I look at the oscilloscope output from syncout I recognize too many spikes between the “normal” impulses. What do you think?
Oh, I see. You didn’t buy our product, but you bought the parts yourself. It’s not cool to ask us for product support in this forum when you didn’t buy the product. I’ve spent a lot of time looking at your problem because I thought there was a problem with one of the devices we shipped.
I don’t know what is wrong with the circuit you built. If you are doing this on a breadboard, then you are going to have all kinds of noise problems. The 680K resistor must be very accurate (1% tolerance), and that’s why I use a 1% resistor in the kit. And sometimes you need to adjust the resistance a bit and that’s why I included R4 in the design.
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