×

INDI Library v1.9.6 Released (21 May 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Flat Panels Question

  • Posts: 683
  • Thank you received: 82

Replied by Peter Kennett on topic Flat Panels Question

Ok, I’m willing to buy all the parts to this project, but I just want to make sure you understood that I need EKOS to control the brightness of the panel, and not adjust the camera exposures as most people do. I want to keep my camera exposures the same and only the light box brightness changes to get my ADU to 13000.

His does the Arduino board change the EL panel’s brightness?  There’s no dimmer controller on them.

Peter

iOptron CEM120 EC2 and CEM25P
Celestron C11 EdgeHD
William Optics Star71
ASI 1600Mm Pro, ASI 462MC
Moonlight motorfocus & Esatto focuser
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4
Last edit: 4 months 3 weeks ago by Peter Kennett.
4 months 3 weeks ago #80094

Please Log in or Create an account to join the conversation.

  • Posts: 13
  • Thank you received: 2

Replied by Nuno Gameiro on topic Flat Panels Question

I made a similar project with this one:
elpanelandtape.co.uk/product/13-x-13cm/

Keep in mind that it's very dificult to use the same exposure for all the filters and adjust only the pannel brightnes.
I have an Atik 383 with a shooter that needs at least 2s of exposure to hide the shadow of the shooter, so i use about 2 seconds expusure with the brightness set to 90 (in a range 0-255) for Luminance, but for HA filter, with the brightness set to maximum, i have to rise the exposure. This will hapen with a DIY Flat Pannel or with a comercial one. It will be the same.

Yes the Arduino board will manage the brightness of the EL Pannel using PWM. The board will receive the value from Ekos (or another client).

A word of advice. It's very difficult to mantain a very low value of brightness of the EL Pannel without flickering (mine starts to flickering at below of a value of 50-60). There are diferent ways to connect the EL Pannel to arduino, some more elaborated then others, but you can start with something as simple as a Mosfet.
So, if you will do flats with a C11 and a CMOS, i have no doubt that you have to use very low values of brightness, or using something to lower the brightness without dimmering the EL Pannel (some sheets of paper, for example).
The following user(s) said Thank You: Peter Kennett
4 months 3 weeks ago #80098

Please Log in or Create an account to join the conversation.

  • Posts: 683
  • Thank you received: 82

Replied by Peter Kennett on topic Flat Panels Question

How far can I have a 13" square flat panel away from the front of my C11 (with dew shield) and still get good flats?
Do I need a much larger panel?
The goal is to automate flats in a remote observatory.



 

iOptron CEM120 EC2 and CEM25P
Celestron C11 EdgeHD
William Optics Star71
ASI 1600Mm Pro, ASI 462MC
Moonlight motorfocus & Esatto focuser
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4
4 months 3 weeks ago #80103

Please Log in or Create an account to join the conversation.

  • Posts: 683
  • Thank you received: 82

Replied by Peter Kennett on topic Flat Panels Question

Nuno, how do I physically connect this to an Arduino?: www.technolight.com/product/14-inch-uv-f...-any-color-or-design

What other items would I need to purchase to make such a connection?

iOptron CEM120 EC2 and CEM25P
Celestron C11 EdgeHD
William Optics Star71
ASI 1600Mm Pro, ASI 462MC
Moonlight motorfocus & Esatto focuser
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4
4 months 3 weeks ago #80108

Please Log in or Create an account to join the conversation.

  • Posts: 61
  • Thank you received: 3

Replied by David Swinnard on topic Flat Panels Question

Regarding the two versions of the Alnitak command sequence protocol (Rev 3 of 2011 and Rev 44 of 2017).

I used the later one for my first cut of Arduino code (using command strings with capital "O" rather than with zeros). Initial testing back in September (Kstars 3.5.5) brought up some issues that Jasem fixed for 3.5.7. With 3.5.7 installed further testing results prompted me to monitor the USB packets exchanged between Ekos/Indi to the Arduino controller. I discovered these commands used the older version of the protocol, the one with zeros. Looking at the indi_flipflat driver source code (flip_flat.cpp) confirmed commands issued use the zeros structure (e.g. "if (!sendCommand(">P000", response))" which results in " >P000CR" being sent to the flat panel's Arduino controller.

I investigated all the Arduino programs listed in this thread but eventually settled on a modified (by me) version of the code found on the gluonfield.com site ( gluonfield.com/spacelike/content/astrophotography-flats-panel ). Basically I went back to using the zeros and the CR an LF command terminators.

As I mentioned I used a DIY LED based solution with a few 3D printed parts (courtesy of my son) to make a panel that slips over my OTAs dew shield like a lens cap. The Arduino with a MOSFET to switch the 12V required by the LED string mount on top of the panel assembly.

Although this flat panel solution has taken months of time and trial and error it did save me some money and provided an opportunity to add to my (minimal) programming and fabrication skills. Being essentially confined to home and literally having no opportunities to take astrophotos since my last session in late October this project along with a dew heater controller has kept me somewhat sane.

Dave
4 months 3 weeks ago #80112

Please Log in or Create an account to join the conversation.

  • Posts: 683
  • Thank you received: 82

Replied by Peter Kennett on topic Flat Panels Question

Thanks Dave. As I have zero electronics skill, and have not programmed since 1984, you are in another league. If you need some extra cash, I would pay you to built a lightbox for me.

iOptron CEM120 EC2 and CEM25P
Celestron C11 EdgeHD
William Optics Star71
ASI 1600Mm Pro, ASI 462MC
Moonlight motorfocus & Esatto focuser
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4
4 months 3 weeks ago #80114

Please Log in or Create an account to join the conversation.

  • Posts: 61
  • Thank you received: 3

Replied by David Swinnard on topic Flat Panels Question

Hi Peter, that's a generous offer, but I can't commit until I know "for sure" this this is going to work. I get back home later this coming week and will actually hook all the components together and finally test in a "real world" environment. I will let you know how things work out...
4 months 3 weeks ago #80117

Please Log in or Create an account to join the conversation.

  • Posts: 61
  • Thank you received: 3

Replied by David Swinnard on topic Flat Panels Question

Hi Peter. Testing this week with my flat panel has shown me more work is needed. Turns out I overestimated the number of LEDs needed. I can barely dial it down enough to obtain multi-second exposures. The control program works fine though and responds to Ekos/Indi as expected.

I have other LEDs on the way but it will be a few weeks before I can get back to the project. (I had the first clear, usable night two nights ago since October 30 so I actually put the flat panel to use where I discovered the brightness issue. The upcoming forecast isn't too promising and the moon is waxing so waiting for LEDs to come isn't an issue.)

If you are interested I can send you the Arduino program and a schematic of the rest of the electrical components needed. The circuit is actually very simple - the Arduino running the code, a MOSFET (acts as an electrically controlled switch), and possibly a few resistors depending on the voltage requirement of the light panel used - LED or electroluminescent panel (EL).
4 months 2 weeks ago #80458

Please Log in or Create an account to join the conversation.

  • Posts: 22
  • Thank you received: 1

Replied by Gord Tulloch on topic Flat Panels Question

Hey guys:

Just found this thread and thought I'd pipe in. I just hacked a flat panel like in this discussion on CloudyNights: www.cloudynights.com/topic/536533-diy-alnitak-flat-panel

Electronically it's pretty simple. You just have to peel back the plastic cover on the back panel of the EL panel (I got www.amazon.ca/gp/product/B07F147VF6this one for my 8" SCT but I think I'll need to get a www.amazon.ca/gp/product/B00ZDCALAE larger one for my new 10" ) cut the wires going to the circuit board (red and black) then connect those to a transister. I connected the wires as per this schematic:



I loaded the sketch from github.com/jwellman80/ArduinoLightbox and it works like a charm, I can turn on the EL panel from INDI control panel. I'd give it a go Peter!

Regards,
Gord
The following user(s) said Thank You: Jasem Mutlaq
Last edit: 1 month 3 weeks ago by Gord Tulloch.
1 month 3 weeks ago #82664

Please Log in or Create an account to join the conversation.

  • Posts: 61
  • Thank you received: 3

Replied by David Swinnard on topic Flat Panels Question

Peter, I finally found time to work on my flat panel some more. The main issue I had was getting the LED string to be dim enough to allow an almost full range of control. Binned 2x2 Red needed a low intensity setting while unbinned H alpha needed almost full brightness to get an exposure time in the range I was looking for ( 2-10 seconds). I ended up with a series of diffusion materials and a 2-stop neutral density filter (stage lighting gel) to subdue the light intensity. The device is held together with masking tape at this time while I sort out a way to easily hold the four main sub-components together.

As a cobbled together device with bits acquired from a range of sources and 3D printed components supplied by my son, I don't feel comfortable in offering to build you one - mine is sized for my GT-71 refractor so it's quite compact. If you decide you want to tackle building one I would be happy to share with you my circuit diagram, program code, and design considerations.
1 month 3 weeks ago #82672

Please Log in or Create an account to join the conversation.

Time to create page: 0.838 seconds