Last updated: 31 March 2009
This page is for user comments and information specific to the Meade DS, DSX, and some older telescope models. Accessories and Feedback items appropriate to the ETX models are posted on other pages as appropriate. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me for posting. Please use an appropriate Subject Line on your message per the Site Email Etiquette. Thanks. Remember, tips described on this site may invalidate the warranty on your telescope or accessories. Neither the submitter nor myself are responsible for any damage caused by using any contributed tips.
Subject: Re: DS-2000 mount controlled by microcontroller Sent: Monday, March 30, 2009 08:09:04 From: richard seymour (firstname.lastname@example.org) > 4. Should I get #497 or similar hanbox with serial interface? If you DO get a 497, get an "old" one... Meade has recently started shipping "497" Autostars with *completely different* electronics inside. My patch kits (nor Meade's ASU for updating) do NOT work with the new model (yet). "old"= manufactured and shipped before Nov 2008. The only external difference is the -lack- of molded-into-plastic printing on the bottom rear (near the connectors) listing Meade's name and FCC compliance information. The only "new" unit i've seen just has a flat surface there, with no raised printing at all. have fun --dickMike here: I wonder if AutoStarX and Lin_AutoStar work with the new model. [They don't; see the discussion on the AutoStar feedback page.]
From: Zbig T. (email@example.com) Thank you very much everyone! I'll keep you informed about the progress. Best regards Zbig
Subject: DS-2000 mount controlled by microcontroller Sent: Sunday, March 29, 2009 12:20:44 From: Zbig T. (firstname.lastname@example.org) I'm happy that I've found this ETX site. I can see lots of information by some very knowledgeable people so I hope someone will be able to give me some hints. I'm planning to use AutoStar DS-2000 mount in my time-lapse/motion control photography project. Initially, I was going to adapt some pan/tilt camera head and fit it with stepper motors until I came by this man's solution: http://www.youtube.com/user/milapse. I think this is great platform to start with: quite affordable, solid and precise. However, I don't like this guy's approach to controlling the movement. I find it quite limiting, not fully utilizing this great hardware's potential, not to mention the "clamp-locking" of the HBX's buttons which is just ridiculous (http://www.youtube.com/watch?v=Ni89TBOTCUA). Therefore, I'm planning to build a custom controller with "record/play" and time-scaling features based on ATMega / Arduino development platform. After some lecture of your site, I've learned that scope's AUX port is essentially an I2C port. I've also learned that I would need at least a #497 to be able to "talk" to the scope using simple UART but I'll get #494 with my set which lacks this additional serial port. Also, I'd like to bypass as much of the built-in logic as possible and, ideally, "talk" with my uC to the motor controllers or motors themselves directly. I'd also need an access to the encoders positional data and again, "raw" data would be best. Is it possible at all to "hook" into the controlling bus/signals and command the motors directly? Do additional pins in scope's HBX socket contain some "low-level" logic signals controlling the drive and reading the encoders directly (would be great!)? I couldn't find any pinout description of the HBX socket (the links on your site do not longer work). I've read that one cannot simply disconnect the handbox as scope's drive behaves erratically at best this way. As a last resort, if any other means of "direct control" fails, I'll stick with "official" command set but effective use of them would be tricky at least in my application. I always could just open the base, disconnect the drive from its "brains", hook to it directly and just PWM-control the motors by myself but I'd rather not as I'm planning to get some scope and use the whole setup the way it's supposed to be used as well :-) So, to summarize, I'll be very grateful for any answers or hints regarding following questions: 1. Is it feasible to directly control the motors movements with a uC using some (unknown to me) HBX pins and access encoder pulses similarly, leaving the original hanbox disconnected or connected but essentially "ignored"? 2. If not, are the motor controllers and encoders tied up to a common I2C bus, individually addressable and controllable? And again - what with the hanbox? Won't it break or "freak out" this way? 3. I all of the above fails, how hard would it be to hook up into the HBX or AUX port and issue "official" and documented scope control commands? 4. Should I get #497 or similar hanbox with serial interface? Would it make my task any easier? Sorry for emailing some of you directly, but I found that you have particularly extensive knowledge about that platform. I hope you don't mind... Again, thank you in advance for any feedback Best Regards Zbig (Zbigniew Trzepizur)
From: Gene Chimahusky (email@example.com) Zbig, My 2 cents The source code that goes with the schematic on the 494 project page. It is PIC based and meant to be compiled with Hi-tech C compiler. http://home.comcast.net/~lynol1000/as_494/as494_i2c_bus.htm http://home.comcast.net/~lynol1000/as_494/as_506_guider_focuser_picc1.zip Q1: When I started on the 494 clone Dick pointed me at the autostar_mtr_2.html file in the Yahoo Roboscope egroup files section. It was a good start but cannot confirm its accuracy as I never controlled the motors via the aux bus. You may want to ask the author of the file. His name is Darren H (dbh@) and he frequents the Roboscope egroup. Q2: The RA, DEC and AUX CLKS's are separate pins via the HBX conteoller but the AuxData line is a single line out and shared between them all inside the 2000 scope base including the Aux socket. You cannot 'take over' the AuxBus with the 497 still attached. Q3: Control via 494/497. Yes, you can put unit into terrestial mode and use large guide commands: :RG#, :Mn#, wait, :Qn# These commands are what the 494 clone uses when used as a guider also. In terrestial mode the micro guide commands are not functional, e.g. :Mgn0100# See http://www.meade.com/support/LX200CommandSet.pdf The :Sa and :Sz commands for goto alt/az are somewhat functional within the limits of the scopes backlash and training. Q4: Get a 497? Yes :-) Gene
From: richard seymour (firstname.lastname@example.org) I'm glad Gene answered first, since it saves a lot of explaining. For the pin-outs, the new location for that helpful page is: http://jan.eaglecreekobservatory.org/pinouts.html A lot of information on the communication protocols are in Meade's patents: primarily: 6,304,376 and 6,392,799 6,445,498 6,563,636 align: 6,922,283 are interesting, too. If you use http://www.pat2pdf.org/ to fetch them, the diagrams come through. The -old- units used separate I2C buses to each axis. The data line is common (in the 494, the AUX data line is common to the motor cards, too... in the 497 it's separate), and Meade only toggles the -clock- line of the axis they wish to talk to. Only the AUX bus makes use of addressed peripherals, the motor busses expect to have -only- their axis' motor on there. The DS200 has, i believe, a -single- circuit card to handle both motors. On all other units (ETX, DS-(less than 2000), LX90, LXD) the two motor circuit cards are separate. I'm a fan of "use a 497", since 95% of the job is done for you. I assisted the "milapse" builder a couple of years ago, and came up with a firmware patch for the 497 which provides individual axis speed control over the serial line (the LX200gps has this, too). Since then, Andrew Johansen improved the patch to operate with true "degrees per second" speed units. So if you use a 497 Autostar, you can immediately control its speed to the limits of the system... from -barely- moving (far slower than sidereal's 15 arcseconds per second) to as fast as the motors will spin (around 6 to 8 degrees per second). That speed is the speed of the telescope itself across the sky. Each motor is individually controlled, so any vector is feasible. You can also send self-timed commands (slew at this speed for this many milliseconds). As Gene suggests, the resources of the Roboscope Yahoo group are a rich source of information, and contacts to other folks who have bent the Autostar system to other purposes (usually astronomical). http://groups.yahoo.com/group/roboscope have fun, keep us posted... --dick
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