Meade LX6

[gryromans]

Dear all,

I have been thinking about trying to mod my LX6 handpiece for autoguiding so have been crusing the shoestring site looking at options. There's lots of great info but I'm confused on one point. The Santa Barbara suggested mod of the LX6 shows 12 wires being connected yet the GPUSB has a RJ12connection which is 6 wires. What am I missing? Has anybody done this? Any help or comments most welcome!

Thanks - Gary

[dpanderson]

Could you please provide a link to where the Santa Barbara LX6 mod is documented?

Thanks,

[gryromans]

Hi Doug,

Thanks for such a quick response. The modification is on the SBIG web site under application notes, toward the bottom of the page. The link is http://www.sbig.com/sbwhtmls/app_notes.htm.

I have also seen a LX200 autoguiding emulator at http://www.technoplus.nl/astro/lx200.htm which seems to have the same 12 wires as the output.

Thanks - Gary

[dpanderson]

Wow, I have no idea what they are trying to interface to. It might be their relay box, but it is not obvious to me. You could try sending them an email.

[gryromans]

Yeah, that was my reaction too. Apparently it was to take the ST-4 signals. Did the technoplus site give any clues as to what these are? My last option is to try and build their board.

Thanks again - Gary

[dpanderson]

It is still not obvious to me from the technoplus website where this plugs into on your mount. I am not convinced that you would need to go to the work of building their board.

Have you seen this document from our website: http://www.store.shoestringastronomy.co ... idance.pdf
This might give you some ideas on how to mod your handcontroller.

Unfortunately, without having access to an LX6, it is a little hard for me to give targeted advice. Sorry.

[gryromans]

Hi Doug,

No appologies needed. The attached is the pictoral from the Technoplus site showing the LX 6 connections from their board to the handcontroller. They reference the SBIG site for the handcontroller modification and I noticed the same wire color coding is used between the two. I'm not an electronics guy but it seemed to me the conection is made into the handcontroller in this way.

Gary

[johnnyac]

Hi all,

I'd like to put this post alive again. Since I also own a Meade LX6 and I need to mod my hand controller in order to be able to use your USB guide interface adapter.
I add the schematic from SantaBarbara, which was missing in the post as an attachment.
I also add a photo of an actual mod from a user on a yahoo group: inkpen3d.

So to put things in clear:
- The image posted by Gary is a homemade emulator to the MEADE LX200 guiding interface.
- The electrical modification showed in this PDF file is necessary in order to work with the emulator mentioned above, but was suggested by SANTA BARBARA. Thus, I believe that SANTA BARBARA did not provide them with just a mod for their emulator, but I think that the mod is for their standard ST4 signals. In fact, If I am not wrong the LX200 standard should be the same as de ST4 with just flipped connection.

If that is the case, I think that the guy developing the emulator linked the SANTA BARBARA mod because it should fit for both interfaces once the connections are properly made.

Looking at the documents I posted I understand that:
- Pink, red, orange, and yellow are sold together trough 4 resistors (in star connection) and should go to the normally disconnected pin of the ST4 port.
- grey, black, green and brown should be connected to the common pin of the ST4 port, which means that differently from this picture in the end they will be shortcut. Since they call it common, there should not be any problem.
- Finally tan, violet, blue and violet should be connected to the other pins and correspond to RA+,DEC+,DEC-,RA-.

What do you think about this, can this mod work in order to accept the output of your USB auto-guide interface?
Thank you for your help, and do not hesitate to tell me if I was not clear enough in writing down my question.

Giovanni

[dpanderson]

Your guidance looks correct to me. I think there is one mistake though, instead of "tan, violet, blue and violet" I think you mean "tan, white, blue and violet".

I believe this will work with our GPUSB. Please post your results if you proceed with this modification.

Good luck!

[johnnyac]

Hi Doug,

thank you for your fast answer. You are right about tan, white, blue and violet. Thank you for correcting me.
I've decided to try this mod, but it will have to wait my next holidays (X-MAS). Once it is done I'll surely post the results.

Thank you again,

Giovanni

[azcharlie]

I see the last post on this subject was almost one year ago. Has anyone made progress with adding autoguide curcuitry to the Meade LX6? I am not a wiz at electronics, but I would think this shouldn't be that hard to do. Of course there are always unanticipated problems.

Rick
Tucson

[azcharlie]

I'm probably just writing to myself, but I don't understand why there has to be so many wires connected to the LX6 handset to get it to work properly with the GPUSB. But, after examining the Santa Barbara schematic for their relay box, their relays are different than those shown on the Shoestring schematics and it would require a lot of wires. I measured the continutiy of the the LX6 switches and they do not appear to simple normally open switches. They are something else. When one side of the switch closes, the other side opens. Is that a SPDT? or what? Does anyone have and electrical schematic of the handset? I can't figure out much from looking at the curcuit board. Has anyone out there actually modified the LX6 handset to work with an ST4 system? Please! I need some help here. If I can get this old LX6 to work with an autoguiding system, it would really make my day.

Rick
W0SKI
Tucson

[azcharlie]

I am talking to myself! I don't think anyone reads uses this forum anymore........

Overnight, I did some research on the relays and Santa Barbara does use single pole double throw (SPDT) relays. That is exactly what is required to work the contacts in the LX6 handset. One side of the switch is normally closed, the other side is normally open. So, changing out the SPST relays for the SPDT (getting confused yet?) relays in the Shoestring schematics should do the trick. To understand it a little bit better, the center contact of the relay switches back and forth and is the common for the switch. With that being said, the number of wires going to the handset increases to 12 if you include all the commons.

The problem I see with using the Santa Barbara relay adapter box is that it needs 12 volts to power the relays. The 12 volts comes from their cameras. If you're not using an SBIG camera, you have to find an alternate power source. I'm not completely sure yet, but although the LX6 runs on 12 volts, I think the power to the handset is about 5 volts. I haven't found 12 volts on there yet. So, if you wire your own relay system, you have to use relays with the lower voltage. If you use the Santa Barbara relay adapter box, you have to find 12 volts somewhere to power it. I also think the wiring is slight different in the RJ11 connector. I think pins 4 and 5 are switched around from some other camera makers.

One thing I still don't understand is why the commons are not tied together. And, why do you have to cut the curcuitry? Maybe there's something I'm missing here.

[azcharlie]

After two years, I am sure I am talking to myself!!!

But, if anyone is still "listening", I did manage to modify an LX6 handset for autoguiding, and it works. I've recently spent several nights guiding using the program PHD 2. While I was guiding through the main OTA instead of a separate guide scope. I got it the LX6 to track for several hours. If anyone has questions regarding this modification I can be contacted at azcharlie@juno.com.

Rick
W0SKI
Tucson, AZ

[dpanderson]

Hi Rick,

I think we do get plenty of listeners, but not many have your experience to be a talker. I really appreciate that you have solved the problem and are willing to share that with others. Thank you for your follow-up post.