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Barn Door Tracker Up and running, but different set up
04-14-2018, 04:52 AM (This post was last modified: 05-11-2018 06:40 PM by jaburkhardt.)
Post: #1
Barn Door Tracker Up and running, but different set up
[Image: SYMbqj.jpg]
So I made some changes to my coding and design to get my barn door mount up and running, without the brain shield since I couldn't get it to work. Here is a picture I took with a d5300 Nikon, with the shutter open for 7 minutes, in my back yard with a fairly high light pollution levels.

[Image: hyqjmz.jpg]

My set up is as follows...

Materials...
*Arduino Leonardo
*Adafruit Perma-Proto Bread Board
*Solderless jumper wires
*solder
*100uf 50v Capacitor
*a4988 driver
*Nema 17 Stepper Motor
*M8 rod 250mm
*Sorbathane (optional-to help eliminate vibration between mounts and parts...had some extra from another project so I used it)
*zip ties
*super glue
*2x 3/8 bolts with nuts (one for camera mount, one for tri-pod mount
*small screws (around 20)
*Green Laser Pointer (the one linked takes special batteries that you need to purchase called 5800mAh)
*Pergear Camera Mount
*8 AA battery holder with dc jack
*two wooden planks, 260cm x 95cm x 12cm
*hinge
*Rubber Bands
*on/off switch for power supply

3D Printed Parts
*jjrobots printed parts Include: small gear, big gear, nut cap & guide, laser pointer
bracket, sight bracket, and rod guide.
*My STL and Autodesk Inventor Files Include: Nema 17 Bracket, Tri-pod base, longer rod guide, cam to insert into guide for nut cap to allow for shutter to be open longer, broken down nut cap for easier printing, 303 laser bracket, 8 cell AA battery holder box, and arduino leonardo box bottom/top/lid.

Installation:

As I said before, the installation is just about the same as JJrobot's instructions for the project. Specifics for me are as follows...

*Distance from hinge to rod = 158mm
*Cam installed on nut cap guide to allow for the shutter to say open longer. Should fit right over top of guide and a bit of glue will hold it in place. I am testing this out hopefully soon to see if it works, so I will keep you updated.
[Image: fBWaFv.jpg]
*Sorbathane was installed between the nut cap guide and wood to dampen vibrations from stepper motor and gears to rod, as well as on top of the nut cap, with some scotch tape covering it to make it slide easier.
[Image: 6Am9gP.jpg]
*2 zip ties wrap around stepper motor mount to limit vibration between plastic mount and metal motor.
[Image: wFmH6o.jpg]
*arduino board box sits on top of mount, held down with super glue.
[Image: TA9d7n.jpg]
*tri-pod base bolted in place and strategically placed so that it helps balance the weight of the mount versus the camera.
*two screws are placed at the back of the mount, one on top, one on bottom, to hold rubber bands so that the mount doesn't fly open and break your camera.
*Camera Mount is bolted to top with 3/8th inch bolt, near the hinge of the mount, giving plenty of space for board box and batteries.
[Image: mYhCLl.jpg]
*put 8 cell battery holder in box, then connected a switch to power supply wires and mounted it into box, as seen in the picture below.
[Image: TdvYbI.jpg]
*taped up the four wires attached to motor so they are more tidy.
*Green 301 Laser mounts glued to either side of the hinge on the top plate. I created my own mounts, instead of using the one made by jjrobots, due to it's versatility.
[Image: TMWrJO.jpg]

Arduino Board and adafruit perma-proto board set up
*as I said above, I did not use jjrobot's brain shield for I could not figure out the connections from the driver to the pins on the arduino board. So I used a prototype solderable board made by adafruit. Set up is below...
[Image: poZFQs.jpg]

Arduino Star Tracker Code
Created my own code for the skytracker, and it seems to work just fine. Probably mistakes within, but as my father told me, if it works, don't fix it. I shall though take suggestions!

Code:
// STEPPER DRIVER CONNECTED TO:
// ENABLE pin: D10   (PB6)
// DIR pin:  D9      (PB5)
// STEP pin: D8      (PB4)
// ratio between the large gear and the small one=0.2549
// Length from middle of rod to hinge = 158mm
// M8 rod rises 1.25mm for every rotation of the Big Gear.
// 15 degrees per hour = rise of 42.3359724mm
// 1/4 degree per minute = .70559954mm
// Rotation of Big Gear for 1/4 degree per minute = (.70559954*360)/1.25) = 203.21266752 degrees
//marked off 203 degrees on big gear and kept modifying step amount and speed until 203 degrees was reached at 1 minute.

#include <Stepper.h>
#include <AccelStepper.h>

Stepper stepper(295,8,9,4,11);
void setup()
{
  //Speed of motor
   stepper.step(295);
  stepper.setSpeed(6);
}
void loop()
{
  stepper.step(295);
}





Any questions or clarifications, let me know. Clear Skies!
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04-16-2018, 05:20 PM
Post: #2
RE: Up and running, but different set up
Great post. May need to contact you for further info.
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04-16-2018, 07:08 PM
Post: #3
RE: Up and running, but different set up
(04-16-2018 05:20 PM)startracker Wrote:  Great post. May need to contact you for further info.

No problem, keep me posted!
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05-11-2018, 08:56 AM
Post: #4
RE: Barn Door Tracker Up and running, but different set up
Hey,

this is great !
I've also tried to build a barndoor tracker based on JJrobots one.
It started last year and I was not successful (yet), but I've been planning on refreshing it and making it work, that's when I've found this new forum thread Smile
In the list of things that were not working as expected is the green laser. Mine is clearly not powerful enough and I simply don't see it. Could you give the model you are using ? Your amazon link seems broken...

FYI, everything I did is published here : https://github.com/dkm/startracker
It lacks some pictures, but I'll try to fix that. My build is a bit different as I'm upcycling parts of aluminum PC case instead of wood.
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05-11-2018, 03:40 PM
Post: #5
RE: Barn Door Tracker Up and running, but different set up
(05-11-2018 08:56 AM)marc Wrote:  Hey,

this is great !
I've also tried to build a barndoor tracker based on JJrobots one.
It started last year and I was not successful (yet), but I've been planning on refreshing it and making it work, that's when I've found this new forum thread Smile
In the list of things that were not working as expected is the green laser. Mine is clearly not powerful enough and I simply don't see it. Could you give the model you are using ? Your amazon link seems broken...

FYI, everything I did is published here : https://github.com/dkm/startracker
It lacks some pictures, but I'll try to fix that. My build is a bit different as I'm upcycling parts of aluminum PC case instead of wood.

The laser is the one seen here... https://www.banggood.com/Burning-Laser-3...42416.html ... it's a green 301 laser. Just let me know if you need anything else
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07-28-2018, 09:53 PM
Post: #6
RE: Barn Door Tracker Up and running, but different set up
hi there,


Im building a very similar set up and I wonder if the jerky rotation of your motor is because its doing full steps and not micro stepping?
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08-08-2018, 11:12 PM
Post: #7
RE: Barn Door Tracker Up and running, but different set up
(07-28-2018 09:53 PM)TuggyLewis Wrote:  hi there,


Im building a very similar set up and I wonder if the jerky rotation of your motor is because its doing full steps and not micro stepping?

Yes, full steps. I am new to arduino code so am trying to get the microsteps to work but haven't been able to do so at the moment. But even with the jerky rotation it still gives me very still photos. If you can figure out the coding to do a smoother motor rotation, please let me know!
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08-12-2018, 06:11 PM
Post: #8
RE: Barn Door Tracker Up and running, but different set up
(08-08-2018 11:12 PM)jaburkhardt Wrote:  
(07-28-2018 09:53 PM)TuggyLewis Wrote:  hi there,


Im building a very similar set up and I wonder if the jerky rotation of your motor is because its doing full steps and not micro stepping?

Yes, full steps. I am new to arduino code so am trying to get the microsteps to work but haven't been able to do so at the moment. But even with the jerky rotation it still gives me very still photos. If you can figure out the coding to do a smoother motor rotation, please let me know!

I am also new to Arduino, so I'm doing a lot of learning! I believe the A4988 driver can do 1/16th micro stepping so would it be as simple as 295x16? I'm probably very wrong...
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