$10 3.5" Screen? Has anyone used one of these?

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5v is great too. I just have a hunch that the voltage regulators on that board are not very efficient. So if we could bypass another component, the watt usage of the screen and board will go down.

If you have the screen with you, could you measure the current going to the 5v input? That way, we could estimate the power usage.
Yeah I’ll check those out if I have a sec tonight.

@link270
That through-hole pin labled VD3 is most likely a direct connection to the internal 3.3v line.
Makes sense, I’ll give it a shot later tonight if I get a sec and report back.
 

Stitches

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So did anybody ever figure out if this screen can be run off 3.3v? And did anybody find out how many watts this runs at? Because if it could run off 3.3v, that would be very convenient, and more efficient because it doesnt have to go through another voltage regulator.
Most screens can be run off 3.3v, you just have to find the right pin to supply power to. Poke about carefully with a multimeter and you'll find it.
 
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Most screens can be run off 3.3v, you just have to find the right pin to supply power to. Poke about carefully with a multimeter and you'll find it.
I checked where you had suggested and at the VD3 hole as well and it shows 3.3V, but when I put 3.3V into it it doesn’t seem to do anything, when I turn it up slightly it starts to come on but is still dim. I may be doing something wrong with my input Voltages though. I’ll mess with them a bit more when I can find some extra time.
 
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@link270
My guess is that the 3.3v line on VD3 is back-feeding into the regulators, creating a drop in the line voltage on VD3. Try measuring the voltage on VD3 while supplying the 3.3v to it.

Secondly, it could be that you are choosing the incorrect place to attach your ground connection. Try using the ground pin directly next to VD3.
 
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@link270
My guess is that the 3.3v line on VD3 is back-feeding into the regulators, creating a drop in the line voltage on VD3. Try measuring the voltage on VD3 while supplying the 3.3v to it.

Secondly, it could be that you are choosing the incorrect place to attach your ground connection. Try using the ground pin directly next to VD3.
I tried grounding onto a few different spots, including the one right next to it. I’ll try to poke around some more tonight.
 

nobble

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I hope we can get 3.3v power off these. I put an offer in for 6x screens @ $3.35 each. :Pigmas:
 
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I hope we can get 3.3v power off these. I put an offer in for 6x screens @ $3.35 each. :Pigmas:
I’ve got a bunch of them now. I put an offer on 10 if then for $40 and got twelve, so like $3.33 each. For that they are a steal!
 
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I’ve had great luck on 5V. I’ve found a few points that read 3.3v, but haven’t been able to get anything to power up off it yet. I’ll probably try again soon though.
 

nobble

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of note, no matter what the internet says, everything i've tried for composite on the Raspi's suggests that the A/V jack is NOT trss or whatever, so keep that in mind when testing this
I'm trying to connect this to a Pi Zero, is that why I haven't got any video? I would have thought this would be an easy wiring and edit of the config.txt for composite video.

Edit: I connected the 5v line like @link270 showed and it worked perfectly. I am so happy to now be able to make a super tiny Pi PC. :D
 
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Doom

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I'm trying to connect this to a Pi Zero, is that why I haven't got any video? I would have thought this would be an easy wiring and edit of the config.txt for composite video.

Edit: I connected the 5v line like @link270 showed and it worked perfectly. I am so happy to now be able to make a super tiny Pi PC. :D
Yeah Pi Zero should be easy enough for composite since there is a connection specifically for it. Fuck all trying to get to to work on a 3 though.
 

fibbef

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I literally never use a pinout when wiring composite on a Pi. I just start by wiring ground to whichever pin appears to be the logical ground then poke around the other pins with the video wire until I get a picture on my screen. ¯\_(ツ)_/¯
 

nobble

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That's how I tested video with my rpi b+ before putting it into a case with a HDMI LCD.
IMG-20150128-00359.jpg

Can confirm blue wire is composite +. Find ground on your own, Sista!
 
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So glad I was browsing the forums and found this thread, I need to get in on this shit. Hope he sends three >:)
0d5c71ac8b6c514a4bf8abb1f407e619.png
 
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