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kirkster501

Flats at 49000 ADU with shortest possible exposure

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Posted (edited)
22 minutes ago, kirkster501 said:

What concerns me is if there is any flicker with the panel on a low brightness setting because at full brightness the panel would be much too bright.... Did you manage to dim the panel down enough with the Arduino so that you didn't need any paper/perspex etc in front of it?

I have no discernible flicker whether on low or at it's highest level. I did use 4 x A2 laser copying paper & 2 x opaque drafting film to dim the panel to a sufficient level so I could produce Lum flats at a very low light & at the other end of the spectrum Ha flats on full brightness. 

Regards powering the Panel. 12v @ 1amp through the Arduino Nano.

Steve

 

Edited by sloz1664

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Posted (edited)

Got this working brilliantly Steve!

I have been thinking about this design  and I am of the opinion that a resistor should be used between the pin 3 and the transistor base otherwise too much current could get drawn from pin 3 when it is in the "on" state.  I put a 330 ohm resistor in there and it works perfectly (BSc Electrical and Electronic engineering class of 1988 ;)   ).

I am powering the Arduino with 5V and powering the panel at 5v by connecting the panel between the collector of the transistor and the 5V pin of the Arduinio.  The emitter is connected to ground pin of the Arduino. Even at brightness level 1 it is still too bright for the 2 second flats i want with my G2-8300 shutter camera so i am going to paste some thick lining paper onto the front of the panel.

I will start another thread on this.

Edited by kirkster501

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2 hours ago, kirkster501 said:

Got this working brilliantly Steve!

I have been thinking about this design  and I am of the opinion that a resistor should be used between the pin 3 and the transistor base otherwise too much current could get drawn from pin 3 when it is in the "on" state.  I put a 330 ohm resistor in there and it works perfectly (BSc Electrical and Electronic engineering class of 1988 ;)   ).

I am powering the Arduino with 5V and powering the panel at 5v by connecting the panel between the collector of the transistor and the 5V pin of the Arduinio.  The emitter is connected to ground pin of the Arduino. Even at brightness level 1 it is still too bright for the 2 second flats i want with my G2-8300 shutter camera so i am going to paste some thick lining paper onto the front of the panel.

I will start another thread on this.

Hi Steve,

Glad to see you have it working. It was mentioned in the original CloudyNights forum regards adding a resistor. I'll certainly add one to my set-up. Are you using a 5v or 12 v panel ?

Steve

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Wow, I shall check into that thread Steve.  Yes without the resistor, the transistor getting turned on would apply almost a short to ground that I would imagine would eventually damage the Arduino.

My panel can take 5v or 12v. I am using 5v.  I may try 3v to see if that dims the panel a bit.

Nerve wracking to break the perfectly working panel to do this mod but was straight forward enough.

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1 minute ago, kirkster501 said:

Wow, I shall check into that thread Steve.  Yes without the resistor, the transistor getting turned on would apply almost a short to ground that I would imagine would eventually damage the Arduino.

My panel can take 5v or 12v. I am using 5v.  I may try 3v to see if that dims the panel a bit.

Nerve wracking to break the perfectly working panel to do this mod but was straight forward enough.

I must admit I had my heart in my mouth cracking open the back of my panel and soldering those tiny wires. It didn't help that my transistor was faulty and my first thoughts were I had damaged the panel :eek: Engineer's head kicked in and found the culprit.

Your next challenge is set your screen brightness for all your filter range :)

Steve

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This is the cracking open bit.  The white plastic sheet actually came away OK with the help of a wood chisel.  Add to then cut the wires, I cut out the small control board and binned it, soldered some longer pieces and then tested it with the 5V bench PSU. 

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IMG_0191.jpg

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Yep it looks the same panel as mine. I can't believe how good a panel it is and for the A2 size,  the price is very good.

Steve

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