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TeenAstro 를 이용한 천체망원경 콘트롤(이건호)

TeenAstro 2.5 엔코더 지원

2023.07.17 17:56

별친구 조회 수:108

I will use the Murata scl3300



Why do we need the WP-109 micro USB adapter. Is it a difference from Teensy3 to Teensy 4?

on the back side of the Teensy 3.2 there are D+ D-  pads that are related to device D+ D- USB connection
BUT for the Teensy 4.0 the pad are for an Host USB. so we need it.




Yesterday I have implemented the Encoder calibration procedure.

the user starts  the calibration procedure in the SHC
The encoder is sync at the current telescope position. the main unit store the encoder pulse position (Ep1) and the instrument position (Ip1)
The auto resync procedure is deactivated!

The user have send a GOTO command with the SHC
The telescope moves and the main unit count the pulse from the encoder
The user then finalize the Calibration
The main unit now read the instrument position (Ip2) and the encoder pulse position (Ep2)
The main unit compute the differences:
deltaE = Ep2-Ep1
deltaI = Ip1-Ip2
we check that both are not equal to zero
then we compute get the rotation direction
reverse = 
deltaE>0 XOR deltaI >0
and finally the number of pulse per degree:
Pulse per degree = abs( 
deltaE / deltaI )
the value are stored in the EEPROM and the user can read the value.

I would like to do the same for the backlash







I am almost done with the encoder support in TeenAstro. It works like it was working in the FS2:

  1. you need a TeenAstro Mini 2.5.x PCB
  2. you will have to sold 4 wires from the bottom part of the Teensy 4.0 to the Teenastro Mini PCB
  3. Then you will need the Main unit firmware 1.3.10 or higher and the SHC firmware 1.3.4 or higher
  4. Then you must configure each encoder there is a gear, a pulse per rotation parameter and a reverse parameter.
  5. it is a bit tricky to get the parameter correctly, I will create an auto calibrate procedure in the SHC and webserver  to simplify the setup
  6. Then you can configure the maximum difference between the telescop and the Encoder, if the difference is bigger than the set tolerance the telescop resync automatocally. it can be deactivated.
  7. The encoder routine use the Telescop alignment
  8. if the Telescop is resync the Encoder is resync too automatically

I played a bit with my em-200 and and a JMI kit





This is exactly the idea to use move the telescop by hand and keep the position... for visual observation you can then keep the pleasure to move the scop and not use goto for any object.
@Boris: I think the encoder on the njp is more or less to obseve the worm gear and a kind of close loop system. Maybe then we have to configure in TeenAstro what is the purpose of the encoder:
* Encoder on Axis (zero point is an option)
* Encoder on Wormgear (need a zero point/ absolute encoder are better)
* Encoder on Stepper Axis (no need for a zero point/ the encoder just check if we are loosing steps)