ArduinoFlatBox RedCat51

ArduinoFlatBox - PC controlled lightbox implmented using the Alnitak (Flip-Flat/Flat-Man) command set found here: https://www.optecinc.com/astronomy/catalog/alnitak/resources/Alnitak_GenericCommandsR4.pdf

Who

Created By: Jared Wellman - jared@mainsequencesoftware.com here https://github.com/jwellman80/ArduinoLightbox
Adapted to V4 protocol, motor handling added By: Igor von Nyssen - igor@vonnyssen.com
Modified to work with servo motors by Marco Cipriani, (GitHub @marcocipriani01)
Modified to work with LDX-227 servo motor,kstars,EKOS by Seadogger, (Github @seadogger)

When

Last modified: 2022/May/22

Usage

Typical usage on the command prompt below. Please note that commands end in CR '\r' and responses end in LF '\n'. Neither end in both, so do not use Serial.println. The character in OOO is the letter O, not the digit 0.

Send     : ">SOOO\r"      //request state
Recieve  : "*S19OOO\n"    //returned state
Send     : ">B128\r"      //set brightness 128
Recieve  : "*B19128\n"    //confirming brightness set to 128
Send     : ">JOOO\r"      //get brightness
Recieve  : "*B19128\n"    //brightness value of 128 (assuming as set from above)
Send     : ">LOOO\r"      //turn light on (uses set brightness value)
Recieve  : "*L19OOO\n"    //confirms light turned on
Send     : ">DOOO\r"      //turn light off (brightness value does not change, just the state of the light)
Recieve  : "*D19OOO\n"    //confirms light turned off

Tested with an Arduino Nano and the NINA imaging software (https://nighttime-imaging.eu)
Tested with an Arduino Nano and the kStars and StellarMate imaging software with Altinak INDI Driver

Bill of Materials for RedCat51mm Telescope

Part Description	Cost	Min Quantity
EL Panel	$19.96	1
EL Panel Inverter	$9.99	2
Driver Board	$11.99	10
Arduino Nano	$19.99	2
Screws	$28.99	50
Magnets	$6.99	100
Capacitors	$10.56	10
Board Terminal Block	$8.99	10
Servo Motor	$19.99	1
3D Printer PETG Spool	$23.99	1
Frosted Acrylic Diffuser	$9.80	1
Arduino Firmware
3D Printer Files
Build Video
Total Cost	$171.24

Other build Items

RedCat 51mm AstroFlat 3D Print Files
PC to program Arduino
USB cable to program Arduino
Soldering Iron and Solder
Allen Wrench Set
Small Phillips Screwdriver

Build Instructions

Switch the PWM and 5V Signal Pin on the LDX-227
Solder Header Pins on the Arduino for the El Inverter
Solder the Cap and Resistor on the Proto Board
Solder the Proto Board to the Arduino Head Pins
Assemble Electronics Chassis

Caution (Know what you are getting into)

Make sure the PWM Pin and 5V line on Servo are swapped and make sure to label the 5V pin. Connecting this backwards can damage the Arduino (You have been warned)
This design was meant for a low voltage El Panel and Low Current Servo Motor to make this a single USB connection to the Telescope controller. Increasing the EL Panel Size or Servo Motor size you do at your own risk and increase the likelihood of damaging your controller
If you notice the servo motor becoming warm then it is likely that the closed or open position is restricted and the servo is in a high current mode. You should disassemble the LID arm and adjust the closing poition of the servo arm. You can also change the PWM open and closed PWM values in the Arduino Sketch to match the swing arm rotation using the constants defined at the top of the sketch
If you are not electronics savy or have a 3D printer then I suggest you buy an off the shelf component such as the DeepSkyDad FP1 or the Alnitak FLipFlat. I had several components above already on hand which lowered my cost to about $100 bucks so I decided to build my own but the Deep Sky Dad solution looks fairly robust and will save you a lot of time tinkering.

Test Results

Test equipment:

ATIK 383L+ Mono (Camera has a shutter so I target exposures on my Flats to be no less than 10sec)
EFW 7 position filter wheel
Optolong 36mm LRGB SHO filters

Test 1: Longest Duration to Create a Common Bin

Filter	Shutter Duration	PWM Setting
LPR	30 sec	119
Red	30 sec	129
Green	30 sec	126
Blue	30 sec	127
H-Alpha	30 sec	190
SII	30 sec	255
OIII	30 sec	149

Test 2: Shortest Duration for all Filters

Filter	Shutter Duration	PWM Setting
LPR	10 sec	128
Red	10 sec	141
Green	10 sec	137
Blue	10 sec	137
H-Alpha	16 sec	255
SII	30 sec	255
OIII	10 sec	173

Test 3: Optimized Durations to minimize Number of FlatDarks Needed

Filter	Shutter Duration	PWM Setting
LPR	10 sec	128
Red	10 sec	141
Green	10 sec	137
Blue	10 sec	137
H-Alpha	30 sec	190
SII	30 sec	255
OIII	10 sec	173

seadogger/ArduinoFlatBox