Flats at 49000 ADU with shortest possible exposure

[sloz1664]

4 minutes ago, kirkster501 said:

Steve,

@sloz1664

Is this the Arduino code you installed on your device to run the panel?

https://github.com/jwellman80/ArduinoLightbox/blob/master/LEDLightBoxAlnitak.ino

You just cut and pasted that as an Arduino sketch? Simple as that?

Thanks, Steve

Hi Steve

Just download the the zip file and expand the files into a suitable folder. I then "double  click" the ino file, it opens the arduino programme and then asks you if you want to put the sketch into a folder, agree and it opens the sketch. You will need to modify the sketch to assign the digital pin 3 output, as detailed in the github webpage. You will need to use an Arduino Uno and not a Nano. I found using 12 volts, especially at 2 amp, overheats the Nano and they will fail at some point. 

Any other queries, please do not hesitant to post.

Steve

[kirkster501]

Great Steve!  Many thanks!  So you drive the LED panel at 5v by coming off of the Arduino Uno 5v pin?????  If so does that supply enough current to drive the panel?

Steve

[kirkster501]

I got the sketch loaded into my Arduino Uno driving an LED perfectly.  I next need to hook it up to a transistor and then hook it into SGP and be happy that all works prior to getting the panel.  It should still dim/brighten the LED a little bit if I just use a couple of levels in SGP

This is a great idea Steve you linked to!

[sloz1664]

58 minutes ago, kirkster501 said:

Great Steve!  Many thanks!  So you drive the LED panel at 5v by coming off of the Arduino Uno 5v pin?????  If so does that supply enough current to drive the panel?

Steve

No the LED Panel is 12 volt. I'm using my existing 12 volt power through the Arduino. That's why I upgraded to the Uno.

Steve

[sloz1664]

Hi Steve,

You could always just buy the Panel & not hook it through SGPro. The panel has 3 separate settings. 25%, 50% & 100%. Low light for  the LRGB & a higher setting for the Astrodon(s).

Steve

[kirkster501]

2 hours ago, sloz1664 said:

No the LED Panel is 12 volt. I'm using my existing 12 volt power through the Arduino. That's why I upgraded to the Uno.

Steve

Got it Steve.  Working on it now

Deffo want to control it from SGP.

[sloz1664]

I've had an slight issue with my LED Panel and SGPro. The dimming feature of 0 - 255 levels goes from bright to very bright, which is no good for a flats through a Lum filter and the minimum requirement of a 2 second exposure for my Atik 383L+. I purchased two pieces of A2 thick opaque drafting film to place over the panel to reduce the brightness, to no avail. Still too bright. I fitted some dark grey material onto the panel,  again too bright. Luckily I have a couple of dimmer units I once used for dew control. Attached one of these and now I have complete control of the LED panel. I will adjust the brightness via the dimmer unit to acheive a 35000 adu at 2 seconds with a Lum filter and the SGpro flat panel setting at zero. I then can set the RGB and NB filters in varying brightness between 0 - 255, via SGPro to achieve the required 35000 adu setting in the optimum time.

Dimmer Switch

 

Steve

[kirkster501]

Thanks for sharing Steve.  I got the Arduino working to an LED just fine.  I am having a problem getting old of a panel though.  The place you linked to no longer has them.  The other A2's on the bay are USB powered ones, which is not what we want....

[sloz1664]

To be honest Steve a 5v LED Panel would work. There is a 5v outlet on the Arduino board. Connect that as your power and you should be good to go.

Steve

[ollypenrice]

My experience of using the dimmer control on a couple or three panels I've used here was not very positive. They seem to introduce flicker. Given that inserting and removing a few sheets of typing paper is both simple and infallible, I've never been minded to search for a more complicated solution! But, yes, I do indeed go for 'simple' whenever possible.

Olly

[sloz1664]

22 hours ago, ollypenrice said:

My experience of using the dimmer control on a couple or three panels I've used here was not very positive. They seem to introduce flicker. Given that inserting and removing a few sheets of typing paper is both simple and infallible, I've never been minded to search for a more complicated solution! But, yes, I do indeed go for 'simple' whenever possible.

Olly

I agree the dimmer control can introduce flicker, which seems to be around the 50% - 75% mark. Having it set at 25% there seems to be no flicker visible. Unfortunately Olly as I'm a Mechanical / Electrical Engineer nothing is simple

Steve 

[kirkster501]

15 hours ago, sloz1664 said:

I agree the dimmer control can introduce flicker, which seems to be around the 50% - 75% mark. Having it set at 25% there seems to be no flicker visible. Unfortunately Olly as I'm a Mechanical / Electrical Engineer nothing is simple

Steve 

Yes, I was thinking to set the panel at 25% permanently and adjust the exposures, or as Olly suggests, keep it simple and get the sheets of A4 out!  Sometimes the mickey mouse option is the best one.....

[sloz1664]

3 hours ago, kirkster501 said:

Yes, I was thinking to set the panel at 25% permanently and adjust the exposures, or as Olly suggests, keep it simple and get the sheets of A4 out!  Sometimes the mickey mouse option is the best one.....

I've been looking into this a little deeper and from what I can gather the mosfet transister in the circuit should render the screen at zero, barely light visible and at level 255 fully on. This certainly does not do that in my set up. The only explanation is I have a faulty mosfet transister. As I have only the one, I have ordered a couple more and they should arrive Wednesday. I will update then.

Steve

[kirkster501]

The transistor should pulse (Pulse Width Modulation) between 0 (fully OFF) up to 255 (fully ON)times a second.  The higher the number of pulses (from the Arduino Pin 3 connected to the trabnsistor base) the more times the transistor will switch off and on and the brighter the panel will be.

[sloz1664]

27 minutes ago, kirkster501 said:

The transistor should pulse (Pulse Width Modulation) between 0 (fully OFF) up to 255 (fully ON)times a second.  The higher the number of pulses (from the Arduino Pin 3 connected to the trabnsistor base) the more times the transistor will switch off and on and the brighter the panel will be.

Fully agree Steve, but when I connect my Panel at 0(fully off) it's bright at around 80% and brightening in pulses to fully bright at 100%

Steve

[sloz1664]

Good news, I have found the problem it appeared to be a faulty transistor. Ordered a couple of replacements (just in case). The replacement transistor fitted and the Light Panel works as it should. 

Steve

 

 

[kirkster501]

I'm struggling to find a 12v panel to complete this.......

EDIT:

https://www.ebay.co.uk/itm/A5-A4-A3-A2-Ultra-Slim-LED-Light-Box-Panel-Professional-5600K-Daylight-Lightbox/182188561408?hash=item2a6b48d400:m:mjbJ3C-OyuU1BlFUHUpcEoA

[sloz1664]

14 minutes ago, kirkster501 said:

I'm struggling to find a 12v panel to complete this.......

EDIT:

https://www.ebay.co.uk/itm/A5-A4-A3-A2-Ultra-Slim-LED-Light-Box-Panel-Professional-5600K-Daylight-Lightbox/182188561408?hash=item2a6b48d400:m:mjbJ3C-OyuU1BlFUHUpcEoA

Hi Steve

I've just completed my Flat Panel project and although it went together pretty easily I found the Panel to be excessively bright. I had to place 4 x A2 sheets of white laser copy paper + 2 x A2 sheets of opaque drawing film to get the screen brightness low enough to take flats with my Atik 383L+ which requires a min 5 seconds exposure to allow for shutter travel.                                This equates to the following Flats exposures to gain 35000 ADU:_

SGPro screen brightness level 15 - 5.85 seconds Lum Filter

SGPro screen brightness level 255 - 15.65 seconds Ha (6nm) Filter.

The point I'm making is that there are 5 volt flat panels available in the market and they should be bright enough to cater for the variances required, without the need for substantially reducing the brightness by adding costly paper / opaque film.

Steve

 

 

 

[kirkster501]

Thanks for sharing Steve. As per earlier in the thread, you could use some white perspex  sheet in front of the panel to dim it down a bit?

[sloz1664]

1 minute ago, kirkster501 said:

Thanks for sharing Steve. As per earlier in the thread, you could use some white perspex  sheet in front of the panel to dim it down a bit?

Yep I looked into this but the shipping costs were rediculous. Plus, at the time, I didn't know how much I had to dim the screen to achieve a successful brightness. as you can see from my  Flat exposures the results are pretty tight over the Lum - Ha range.

Steve

[kirkster501]

16 hours ago, sloz1664 said:

Yep I looked into this but the shipping costs were rediculous. Plus, at the time, I didn't know how much I had to dim the screen to achieve a successful brightness. as you can see from my  Flat exposures the results are pretty tight over the Lum - Ha range.

Steve

You could buy some clear perspex from B+Q and white wash it with several coats to get an even finish.

[Davey-T]

You can get what they call milk white plastic in thin sheets 300 mm square off EBay.

Dave

[kirkster501]

Steve, what drawings did you follow to build the box power input to the panel please? Did you provide a separate feed for the 12v to the panel or did you just come off of the Vin pin for the 12V?  Surely the Arduino can't provide enough power to light the panel just from the Vin pin (albeit being switched south of the panel via the transistor).

I got my panel and have hung some wall lining paper in front of it to dim ti down.  But I'd still like to do the Arduino automation.

[sloz1664]

Hi Steve,

This is the circuit you want:-

I used my obsy 12v dc supply fused to 1 amp through the arduino Uno. These work well with 12v through the vin pin. I would only use a max of 9v with a nano. I must admit mine is working well with SGPro and once the flat settings are adjusted per filter they are producing flat frames with pretty accurate adu figures.

Good luck on your build. Any questions, just ask

Steve

[kirkster501]

Wow, many thanks Steve! 

So the power and current is fed entirely from the Arduino Steve?  You don't to run a separate 12v to the panel - it's all done from the Arduino? 1A is enough to light up the panel?

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?