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INDI Library v1.9.9 Released (30 Nov 2022)

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

Astroberry Focuser with Adafruit Motor HAT

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I don't have any feedback. I've set it up so that I can manually get close to focus, then engage it for automation
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
5 years 8 months ago #16613

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So, the Driver assume an offset on startup (last saved/used etc)? (I'm struggling to understand how the software avoids hitting the end stops without some level of manually intervention.)
5 years 8 months ago #16637

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I assume that there are many ways to approach this. For example in astroberry focuser I assume that focuser always stars from 0 (maximum inward). As the result it must be parked from whatever position to 0 at the end of a session. Another thing is making sure that it does not exceed maximum steps allowable for a device, which is device dependent. I have used various focusers and I noticed that they rarely travel more than 20000 steps. So in astroberry I hardcoded this value as a maximum. In reality focus point never reaches this value. At the first use of a focuser I manually push it to mechanical maximum outward and remember the value or save it in focuser preset.
All of the above applies for absolute position focuser, for repetitive focus position for each session. If you don't care about absolute position and move a focuser manually close to focus point and then use stepper motor to get precise focus you just need a relative focuser which can travel both ways. However the latter approach makes it hardly possible to define min/max for focuser travel... because you don't really know your starting position. In such the case only min/max hardware sensor can help. None of focusers I know is equipped with such a sensor. This loops me back to approach no 1.
--
Radek Kaczorek
Astroberry Server | Orion CT8 | Askar FRA 400 | NEQ6 (hypermod) | Atik 460EX | ASI 1600 | ASI 120MM | Atik EFW2
5 years 8 months ago #16639

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I haven't got a clue how many steps I'll need with my gear ratios. I hope 20,000 is enough. When I get home I'll try to calculate it.

Edit: Good news. Assuming I am not in error. My creation takes about 14,252 steps from full in to out.
Initial gear ratio is stepped down to 50.9:1. I have then stepped it back up 1.25x with a set at 25:20 for an effective reduction of 40.72:1.
At 200 steps per revolution. I need 8144 steps to turn my focus knob once. And the focus knob turns 1.75x from full into full out. For a total travel of 14,252 steps.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
Last edit: 5 years 8 months ago by Andrew.
5 years 8 months ago #16641

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I think the motor HAT work with Pi3, as its the same GPIO layout (might want to Beef your power supply up though). I haven't checked the HAT Software drivers out, but I image that they will only be dependent upon Python versions 2.7 or 3, and so not a Pi2/3 issue.
regs
rob
5 years 8 months ago #16691

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Thanks Rob. As you said it should, and indeed from my experience with one does work with the Pi3. The HAT also requires it's own power supply as it can not draw enough from the GPIO pins. There is also space on the HAT for extra custom circuitry to match the voltage requirements of the motors being used or what have you.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
5 years 8 months ago #16697

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Hi Kaczorek! Excellent work on the Astroberry Server. I know that's been keeping you very busy so take your time on this, no big rush. I have just about worked out the final iteration and will be releasing the STL files for anybody who can make use of them. Thanks Again.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
5 years 8 months ago #16784

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I'm glad you find it useful. I should find time for the Adafruit Motor HAT driver soon. Stay tuned
--
Radek Kaczorek
Astroberry Server | Orion CT8 | Askar FRA 400 | NEQ6 (hypermod) | Atik 460EX | ASI 1600 | ASI 120MM | Atik EFW2
5 years 8 months ago #16785

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Kaczorek: Will there be an option for backlash steps?
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
5 years 8 months ago #16845

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Why not ;-)
--
Radek Kaczorek
Astroberry Server | Orion CT8 | Askar FRA 400 | NEQ6 (hypermod) | Atik 460EX | ASI 1600 | ASI 120MM | Atik EFW2
5 years 8 months ago #16852

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Excellent! I'm looking forward to giving this a spin.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
5 years 8 months ago #16853

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There's really bad news on this driver. Adafruit provides only python library for this board and no c++ library is available that can be used directly. As the result a driver for this board needs to use low level PCA9685 driver (which basically means writing everything from scratch) or bind python library into c++ code (which reuses the library but still requires lots of coding).
In summary, for now a stepper focuser build on Adafruit Motor HAT can only work outside of INDI, controlled with python scripts released by a vendor. Integration with INDI will be possible if c++ library is available for the device.
--
Radek Kaczorek
Astroberry Server | Orion CT8 | Askar FRA 400 | NEQ6 (hypermod) | Atik 460EX | ASI 1600 | ASI 120MM | Atik EFW2
5 years 8 months ago #16883

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