Telescope Control Project

Wanna make a scope? Or better still, grind a mirror yourself. Or, you have some good tips in making a really useful accessory? This is the place to show what your hands can do...
mitoo
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Real time

Post by mitoo »

Real time is a big problem. those claculation makes mcu ver slow. therefor i use mutiple mcu. they don't interfare when they calculating or motor is running in real mood. they all are sharing same Sram or other communication to communicate without interfare each other.

Example: keypad 16f84, LCD 16f84, main 16f877, convert alt, az 16f876, converting date and time into MST 16F876, calculate moon possition 16f876, converting planets possition 16f876, real time keeping 16f84. some i could put into main mcu but not enough pin.

thank you
michael
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river
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Post by river »

so how many uP you had in your design?

The Nexstar handheld controller use one PIC17C756A (with 50 I/O) and a total of 1MB flash. The CG5 mount have two PIC16F876, each controlling a motor driver. If you want to maintain your 40pin footprint and the tools, then the pin-compatible PIC18 family with higher MIPS and clock speed is a good option.
mitoo
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Microchip

Post by mitoo »

river wrote:so how many uP you had in your design?

The Nexstar handheld controller use one PIC17C756A (with 50 I/O) and a total of 1MB flash. The CG5 mount have two PIC16F876, each controlling a motor driver. If you want to maintain your 40pin footprint and the tools, then the pin-compatible PIC18 family with higher MIPS and clock speed is a good option.

//
This type of project should be used 18F type but I can't due to compiler problem. I only have Hi Tech c and CCS; Hi tech C only allows pic16f84, 16c678, and 16f84a. CCS, I can use others but all are 16F. I can't use 18F.

I have downloaded C30 but can't figure out. Also I don't know how can I solder those 100 fine pins. I already checked the chip.

My first project, I successfully control via LPT port on PC.

Only Two months ago, I was thinking if I could do in microchip, I don’t need to use computer. So I started to learn about MCU. I never had any exp about microchip.

Already done 70%. Calculation is completed but I am now solving problem for i2C. You have lots of exp. about MCU. I am not Electronics Engineer. I am just an electronics hobbyist.

I have forgotten to tell you still have time keeping chip DS1337.

Can I ask you one question; if I want to calculate cos. sin asin in c, how can I use looks table or other option to save memory. Is there any other option? My program taking too much memory, all variables must be in float.

Thank you.
Michael
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river
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Post by river »

What tools are you using? ICD2?

There are things like QFP/SOIC to DIP adapter, or you can get a QFP/SOIC socket for your IC. The Socket will have easier pin to solder so and you do not need to solder the PIC to board, that should solve your "fine pin soldering" problem.

about I2C :microchip I2C If your PIC do not have build-in I2C controller, you have to look at the timing diagram and use two of your I/O pin to simulate the clock and data line.

There are a few ways to do trigo function but each come with its cost. Using lookup table is mainly to save the time taken to do complex calculation at the cost of memory space. I am not sure will this solve your limited memory problem until you find out the size of your lookup table and the size of the function code.

It is much more "fun" to do a pure micro controller GOTO solution, Yet, an another way is to use a PDA for User-Interfacing, Calculation, time control + Database and use two PIC to drive and track the motors. Just like Nexstar or Autostar VS Vixen's Starbook.

Just close two small project yesterday. Now have more time to try out C30 myself and do something similar :) Will like to learn from you about the calculation and database design.


#foot note,
PIC = refer to the processor IC make my Microchip.
ICD2 = a development tool by a Microchip.
DIP,QFP,SOIC = refer to different packaging standard of an IC. like beer can pack in botlle, can, jug etc.
I2C = a way of communication between IC chips using single data line.

Celestron are using Microchip processor for their GOTO.
mitoo
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Microchip

Post by mitoo »

Hi,

Thank you for your advice.

Yes, it is much fun to do in micro. PDA, I think have to use RS232 port to control. PDA will be easier to control but I have no exp on this. May be its need different compiler to compile. Have you decided which type of mount or gear, is u going to use? Ha. Ha. This is another great problem.

Database design. I used Microsoft access file for PC control but for MCU I use Eeprom. Calculation I s not a great deal.
Let me know your progress.


Thank you
Michael
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weixing
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Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
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Post by weixing »

Hi,
I'm also quite interested in this, but don't have time to do it.

Anyway, I just wonder how you guys do the alignment calculation?? May be can create a new thread on "Astro Computing".

Have a nice day.

PS: I'll move this thread to the "DIY Astronomy" section.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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river
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Post by river »

I wish I have some trainning in Mechanical Disign. I dont think I know who to DIY the GOTO gear+motor. Maybe I should start with a 8" Dob GOTO project, any suggestion on the motor and gear?

For PDA, you have to first select which OS (Palm, WinCE etc.) coz the tools will be different. The PDA model must have a RS232 adapter available. It is like creating Visual Basic project, download to PDA via cradle. Then connect the PDA to a motor controller board. Look at the link to Anat's project on my previous post, all he need is to interface with motor controller.

Michael: Where did you get the data for your database?

WeiXing: designer have to decide how much sensor we need and how much human effort it will take to align the scope. Common way is for the user to center a star then sync that to database. The calculation is depend on how much the user need to do to align the scope.

It will be great if we can do everything auto. Eg. you power on, Point to any bright object, center it -- done! your dob is on GOTO now. I have this idea some time ago and celestron had somehow answer that with Sky Scout!!

Make the Sky Scout your optical finder scope and interface that to a motor controller board... and you got a "Lazy Mount". I like to know what type of sensor they use in Sky Scout. I guess it must have a Gyro compass, some Roll sensor and a GPS receiver.
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weixing
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Post by weixing »

Hi,
I mean the calculation dealing with alignment without additional sensor, such as 1 star alignment 2 stars alignment and 3 stars alignment.

Have a nice day.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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river
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Post by river »

Michael: You want to give some idea on the alignment part?

Also, I assumed most star database will give you data in Hour,min,second format. Will it be easier for the non-GEM GOTO controller if we convert these data to X,Y,Z format then store them into database.
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river
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Post by river »

hi Michael, WeiXing and other electro-Astro DIYer :
just found out there are free Microship Hand-on cource by microchip's vendor on Tomorrow(Full) and 27 Mar. They provide Explorer 16 board, PIC24 and C30 for the training.

Explorer 16 come with 100 pin PIC24. Take a look, can use as project board and save you a lot of development time. You can then ask your question regrading C30.

https://secure.microchip.com/RTC/details.aspx

look at the special price for the tools and C30 !!... (now so cheap)
quick grab the tools you need! (eg. the ICD2 + Explorer16)

Next seminar by microchip is around Jun..
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