VU7A+ - Multiple Questions

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FntX
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VU7A+ - Multiple Questions

Unread post by FntX » Sat Jun 15, 2019 5:46 pm

Now that I can finally hold it in my hands it quickly raised some questions :)

1) When the display has no signal it displays "no signal". Is there a possibility to circumvent that?
2) Is there a way to hook onto the brightness control so I can control it externally?

//EDIT: Made a Mistake. I own the VU7A+
Last edited by FntX on Sun Jun 16, 2019 4:39 pm, edited 1 time in total.

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Re: VU7+ - Multiple Questions

Unread post by mad_ady » Sat Jun 15, 2019 6:13 pm

For #2 - search odroid magazine or the wiki - if you solder a resistor in some spot you can connect it to a pwm signal that can drive brightness control.
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Re: VU7A+ - Multiple Questions

Unread post by odroid » Mon Jun 17, 2019 1:29 pm

There is no way to disable OSD feature of the Vu7A+ unfortunately.

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Re: VU7A+ - Multiple Questions

Unread post by FntX » Mon Jun 17, 2019 5:27 pm

Unfortunately I wasn't able to locate the right chip on the board to regulate the brightness. It's somewhat different than on the Vu7. There is a 4103 Chip but this one has no PWM input for brightness control.

I hooked into the power button of the display so I am able to turn it off when the Odroid is in a sleep state. When the Odroid is coming up again, the display will turn on again by itself. I planned to remove the button completely but that would've been stupid :)
That display button works via a pulldown mechanism. It simply shorts the pin to ground. I'm now using an opto isolator, with 470R resistor in front as a safety measurement, via my external power management arduino. That does the trick because I want to drive the whole setup as power efficient as possible.
Last edited by FntX on Mon Jun 17, 2019 5:33 pm, edited 1 time in total.

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Re: VU7A+ - Multiple Questions

Unread post by odroid » Mon Jun 17, 2019 5:31 pm


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Re: VU7A+ - Multiple Questions

Unread post by FntX » Mon Jun 17, 2019 5:42 pm

odroid wrote:
Mon Jun 17, 2019 5:31 pm
Did you see this wiki page?
https://wiki.odroid.com/accessory/displ ... th_android
Thanks, yes - but I want to use my cars light level sensors to dim the display.

I was mildly confused while looking at the datasheet but this one is the right chip on the Vu7a+:

Image

The red area is the lane to the EN pin #4 and can be controlled like on the Vu7. A truly HUGE area to solder on for people like me without SMD soldering skills :)

I'll try this out...

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Re: VU7A+ - Multiple Questions

Unread post by mad_ady » Thu Oct 03, 2019 11:28 pm

@FntX: Have you modded your VU7A+ to support PWM backlight adjustment? If yes, where/how did you solder the resistor? I too want to mod it and my soldering skills are problematic.
Did you use a knife to scratch your way to the PCB layer? Have you soldered the resistor leg to one of the resistors below?
What resistor value did you use?

Any tips/pictures are welcome!

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Re: VU7A+ - Multiple Questions

Unread post by joerg » Tue Oct 08, 2019 12:16 am

@mad_ady: As you can see in my original post, the resistor first should be fixed. I had to make again at one of my VU7+, because the resistor was not fixed anymore. So I can cannot recommend the superglue I used (here in Germany we say: Sekundenkleber). Now I used a 2K glue, this should fix the resistor now for longer time. When it is fixed, you can bend a wire to the pin4 of the 4103 and cut it there exactly. Now you need only short contact with the solder iron and a small amount of solder wire. No long contact to not to overheat the 4103! That's all.

viewtopic.php?f=113&t=27227
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Re: VU7A+ - Multiple Questions

Unread post by mad_ady » Tue Oct 08, 2019 1:23 am

Thanks. I'll try with hot glue. Is a 330 ohm resistor fine, or do I need a specific value?

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Re: VU7A+ - Multiple Questions

Unread post by joerg » Tue Oct 08, 2019 3:21 pm

The 330 ohm resistor is fine.
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Re: VU7A+ - Multiple Questions

Unread post by mad_ady » Fri Oct 18, 2019 2:04 am

I confirm that the mod worked, but my soldering is shoddy and the contact between the IC pin and resistor only works when pressed with a finger
I need to heat it up more...
I was surprised to see how well the dimming works - I expected to see flickering (tried with a pwm from an N2).
Next (after fixing the solder point) will be getting a pwm from the c2...

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