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20 Aug 2017
INDI development team is happy to announce the release of INDI Library v1.5.0. This new exciting release builds on the maturity of INDI Library and comes with many new supported devices and fixes for existing drivers.
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TOPIC: Astroberry Focuser with Adafruit Motor HAT

Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16613

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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

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Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16637

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.)

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Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16639

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.

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Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16641

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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.

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Last Edit: by Ihoujin.

Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16691

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

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Astroberry Focuser with Adafruit Motor HAT 5 months 1 week ago #16697

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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.

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Astroberry Focuser with Adafruit Motor HAT 5 months 2 days ago #16784

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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.

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Astroberry Focuser with Adafruit Motor HAT 5 months 2 days ago #16785

I'm glad you find it useful. I should find time for the Adafruit Motor HAT driver soon. Stay tuned

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Astroberry Focuser with Adafruit Motor HAT 5 months 1 hour ago #16845

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Kaczorek: Will there be an option for backlash steps?

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Astroberry Focuser with Adafruit Motor HAT 4 months 4 weeks ago #16852

Why not ;-)

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Astroberry Focuser with Adafruit Motor HAT 4 months 4 weeks ago #16853

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Excellent! I'm looking forward to giving this a spin.

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Astroberry Focuser with Adafruit Motor HAT 4 months 3 weeks ago #16883

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.

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